Category Archives: Information & Education

Protect the Water of Dearborn County

The Sun Sets on Dearborn Co
A disturbing situation plays out in one community after another. A water supply is contaminated. A community is kept in the dark while a widespread health crisis emerges. Scientists establish an undeniable link, but the community is forced to fight with the very officials entrusted with their protection. Sometimes the officials face justice, but the community is always devastated; courts can’t cure cancer or reverse nerve damage.

The fate of such communities depends on outside intervention – usually a news agency with a sphere of influence larger than the local government. Even so, resolving a water crisis can take a decade. Imagine your entire childhood being overshadowed by suspicious illnesses and fears about loved ones. And now imagine that you could prevent everything. Imagine that you could identify the threat to the community before it poisoned its first victim. Imagine that you have the knowledge and ability to devise a solution that protects everyone from harm, and even revitalizes the area with an economic surge of hundreds of millions of dollars in the process. Would you speak up?

Imagine that you tell your local leaders, who assure you they’re taking action, but secretly aren’t. What else can you do? Imagine that you go to the news and discover that no one will dare to speak. Imagine that in your frustration you somehow scream loudly enough that your message reaches the public anyway – only to find that now… now you’ve made the officials angry.

Suddenly the news is willing to speak, but the article doesn’t contain your evidence & information. It doesn’t mention your potential to benefit the community. It contains only fabrications about you and those working with you.

So imagine that all your efforts to help your community are undermined. You have been cast as an enemy of the very people you’re trying to protect. You are facing an enemy much larger than yourself. The crooked businessmen sit on the board of a bank holding, while you have no resources with which to fight. Are you beaten or do you just have nothing left to lose? I don’t have to imagine what my answer would be – this is my reality.

Never forget that people exist in every community with the ability to lie to your face so convincingly that you love them for it. Never forget that there are people who would deplete the community coffers for their own personal bag of gold. The snake may have a silver tongue, but he is venomous all the same.

To learn more about how you can help, click here for more details.

Water Protection

The goal of this page is to bring all of the information into one place. This story began when the fly ash proposal was made public, and these events ran silently parallel to what was visible in the public eye.

When this began, very little information was available, and none of it was about the Tanners Creek site specifically. As a scientist, I place a high value on information. I believed that with better information, our leaders and the public could make better decisions. Looking back, I feel embarrassed to admit that ever I thought things could be that simple.

But I used my skills to assemble information from every source I could find. I compiled information from IDEM, from our library’s local history office, from local utilities, from engineering firms and research publications, from the DNR and the county surveyor, and even from citizens who had been involved first-hand.

The information began to coalesce into a bigger picture. It showed that the landfill holding the public’s attention was the least concerning section of the property. It was also where I discovered the first of this company’s lies. Everyone knew this company had struck a deal to bring in coal ash from Dayton Power and Light for $7.5m. But the truth about that deal was hidden deep within thousands of pages of documents filed with the state.

That deal was arranged immediately after falsely assuring IDEM that they had no intentions to bring in waste from off-site. Then, they quietly filed for an insignificant modification. It was a dark gamble that would have considerably harmed and undermined the community, had it succeeded. Insignificant modifications aren’t usually scrutinized, and gain automatic approval after 30 days unless IDEM objects. Fortunately for our community, IDEM did object – although they didn’t notice the deception.

And so Tanners Creek Development, LLC was required to submit proper paperwork for the proposal, which included the notice that raised in the public’s attention to the matter. It also included a document called a Good Character Disclosure Statement, which would lay the foundation for the entire controversy to come.

Propelled by the discovery of one lie, I decided to investigate this company. Who was Tanners Creek Development, LLC, and where did they come from? That answer would turn out to be incredibly complex and elusive. Due to the Roberts Brothers’ practice of using disposable LLCs as the front company for each project, we still don’t understand the full extent of their deception and reckless disregard for public safety.

Alarming press coverage and records of violations could be found surrounding each LLC that I investigated. In North Carolina, they lied to investigators about the incompatible types of hazardous waste they were illegally concealing in semi trailers. They caused a portion of Grand Rapids to be evacuated when the state discovered toxic gas levels nearly 30,000 times above acceptable limits. Marysville has been mired in lawsuits for years over their failure to deliver on their redevelopment promises, scaring away any potential buyers. The list goes on and on. And none of this information had been included in the Character Statement. They had lied numerous times on a document in an official proceeding with a regulatory agency. Not only is that opposite of good character, its perjury.

Although a dark cloud surrounded every site they had touched, it never cast a shadow over the central corporations. The press coverage was always limited to the LLC itself. No one had ever made the connection, and the negative consequences were always discovered after the fact. No one had ever been in a position to be proactive – to protect their community before the damage was done.

I had never met our community leaders before, so I wasn’t sure what to expect. But I felt obligated to act, so I reached out to our community leaders. I quickly arranged a meeting with Shane McHenry myself, and obtained a professional reference urging Mayor Kelly Mollaun to hear this information. Despite this (and contrary to state law), Mayor Mollaun declined to meet and ignored all future correspondence.

When I met with Shane McHenry, I was assured that the information would be delivered to the state. He also urged me not to disclose the information about the company, claiming that the “investigation” would be harmed. It would be over two months before the community would learn that Shane had lied, repeatedly;  that the information was never delivered to the state, and that no investigation had ever taken place.

A commissioner’s meeting was scheduled for the next day and the fly ash ordinance was on the ballot. I knew I couldn’t be placed on the agenda with so little notice, so I prepared a document that summarized the concerns and set the stage for further discussion.

I urged caution, explaining that the text of the ordinance potentially exposed the county to litigation, and recommended extra time for revision. And I also explained that while the public’s concern was warranted, the most significant threats had not yet been disclosed.

Tamara Taylor, editor of the Bright Beacon, met with me for over three hours to discuss the additional information I had referenced. I was asked to write an article before the looming deadline, and I frantically obliged.

Meanwhile, members of community continued to express growing concern about the lack of information being provided. Citizens asked why our community leaders weren’t providing answers. In response, I organized a public information meeting with the official support of Shane McHenry. He requested that I also secure the attendance of Randy Turner and Olin Clawson, both of whom agreed to attend.

But then the phone rang. It was Tamara from the Beacon. She had shared my article with the county commissioners, and they instructed her not to publish the story because “the public wasn’t ready for this information”. The next day, I was informed that the public information meeting was also cancelled, because Shane McHenry didn’t think anyone would attend and the rest of the commissioners didn’t want to commit the resources.

I offered to present before SIRPA as a compromise because the information was still important for local decision-makers. I explained that the port board consisted of most local officials, and that a meeting was scheduled for the following week. Shane said he wouldn’t object if I could get on the agenda, but that I would need to meet with the board members from the public sector in advance. That was a long list, and there was less than a week before the meeting, but I succeeded.

Mayor Alan Weiss: Listened patiently, summary comment was: “It sounds like Lawrenceburg needs to act.” Insisted he would relay the information to Al Abdon himself.

Terri Randall: Understood the value of the information and attempted to facilitate meetings and discussions. Sincerely interested in the potential involvement of another fact-oriented individual in local issues. Stated “You probably know more about this site than anyone in the state. An investigation of this depth would have cost us at least $30,000.”

Bryan Messmore: Thoroughly understood the challenges facing infrastructure development at the site. Was understandably concerned about open conflict with a large property developer, but reacted responsibly and attempted to arrange a meeting with Mayor Mollaun.

Mayor Kelly Mollaun: Again refused to meet / respond. When encountered by chance in public, stated that he had taken my evidence to IDEM, who decided not to do anything more. This was suspected to be a lie at the time because he was not in possession of my evidence, and this was confirmed to be a lie at the June 5th meeting by IDEM themselves.

Guinevere Emery: Very professional and asked very good, tough questions. Thanked me for my involvement.

Mayor Donnie Hastings: Was thoroughly intrigued by the information and content, and placed me on the meeting agenda.

The Aurora & LMS (not LMU) Wellhead Protection Meeting also took place during this time. The engineering consultant said it was one of the best he had ever seen. I was able to supplement their existing groundwater data and provide the Aurora city attorney with information he had sought for a month. Again I was thanked for my involvement by all attendees.

At the SIRPA meeting, I explained circumstances surrounding the entire site, including the problems at each ash impoundment. I presented monitoring well data which showed the threat of future contamination. I also explained the old indemnity agreements and modern regulations that would let the community correct them without spending a dime. And I also explained that by cleaning up the old ash area, the community would earn hundreds of millions of dollars and have more space available for redevelopment. I handed them a proposal where everyone wins – the threat of contamination was irrelevant, that just accelerated the available timeline.

Everyone, including Shane McHenry, thanked me for my information, and expressed their appreciation. Mayor Hastings assigned Andy Baudendistel (the SIRPA/county attorney) to act as the primary point of contact, hedging that they may not want to act on the information.

But the concerns were about to take on an entirely new tone. Immediately after that talk, former AEP employees began to reach out. Everyone who witnessed the transition had the same message: This redevelopment company was bad news. That sentiment was unanimous. Some knew of unreported spills. Some knew of cut corners. Some knew of public safety violations and fire hazards. But everyone knew that this company was willing to stoop to any level to get what it wanted. Unfortunately, I never predicted that our local government was the first well this company poisoned.

I attempted to inform Shane McHenry of the allegations. “Thanks for passing it on.” But as before, there was no investigation. So I consulted an attorney and brushed up on what I legally could and couldn’t do, and armed myself with loopholes and workarounds involving high powered optics and aerial drones. I conducted the best investigation I could within the law as a private citizen. And again I returned to Shane McHenry and said this is serious… but I would never receive another response. The election had ended (and with it, his responsibility as a law enforcement officer apparently).

So again I reached out to the two attorneys. I understood that these were part time positions, and that I would only see action if I did all of the work for them up front and served it up on a silver platter. But even this was not enough.

I followed up once a week, explaining each time that the urgency level had risen dramatically. I explained activities taking place at that property were criminal and constituted a major threat to the public. Despite this, I seemed to be trapped in a twisted game of keep-away where no one wanted to be in possession of the information necessary to protect the community.

It was now clear that there was no investigation to protect, so I broke my silence and took the information public. I first spoke in Dillsboro, explaining all of the information and the officials’ inaction. This first video was removed from Facebook due to erroneous “report flooding” coordinated by Pam Carter-Rigaci. Shorter digests of the information were put out over the following week while the officials refused to address the public’s concerns.

I also went to Eagle and presented Mike Perleberg with the all of the evidence about this company. After jotting down a few notes, he said he wasn’t sure they would run a story. After seeing no action or follow-up the following week, I fumed on social media about the local media’s refusal to cover a topic so important to public safety – to surprising enthusiasm. Mike Perleberg finally conducted an actual interview after his excuses fell flat.

Fox 19 interviewed us, and within minutes of airing the story, Mayor Mollaun began desperately begging for a meeting (after refusing to meet for over two months). They intimidated the news station with legal threats and demands. Without a scientific credential between them, they ran disparaging Facebook ads. Concerned citizens take note – this is how the City of Lawrenceburg rewards those who stand up for the community.

Mayor Mollaun, Andy Baudendistel, and Shane McHenry issued a public statement in which they lied about our actions; lied about the last inspection’s findings; and demonstrated their failure to comprehend the matter by citing irrelevant data from the wrong wells.

By the following morning, it was clear why Mayor Mollaun had refused to meet. Quite literally overnight, the mayor threw in with the very property developers poisoning the community, and illegally used taxpayer funds to reserve Ivy Tech for a joint public meeting scheduled with IDEM as a closure plan meeting (to start the clock), but outwardly portrayed as a town hall.

An article also finally did appear on Eagle 99.3 – after the TV news coverage. Curiously, although the interview supplied an overwhelming amount of evidence surrounding this company’s numerous violations and threats to public safety, none of that information appeared in the article. What did appear, were manufactured quotes and unsubstantiated criminal allegations about the citizens who brought the concerns to light. After the damage was done, these were quietly removed with no statement of correction or retraction.

The June 5th meeting was more performance art by the city of Lawrenceburg than a town hall. Questions were discouraged until after the news cameras had left, while Del Weldon monopolized 80 minutes of the meeting in a scripted presentation with this company. They called Olin Clawson – a career politician from New Mexico who appears confused about where his wells are even located – to read a fluff piece. Meanwhile, Randy Turner – a lifelong resident and 20+ year superintendent of the wellhead actually endangered – was ignored in the back of the room.

Inadequate attention was given to the actual pond whose closure clock was started, and many citizens still do not understand the circumstances in question and the matter at stake. The IDEM representatives were also completely unprepared for what they were about to walk into. Lawrenceburg had not informed them of the meeting’s dual purpose, so many of their responses were non-committal and vague. This was explained in detail in this live video.

And that brings us to today. Our local officials are determined to do only what is necessary to quell the public interest. Everything here has proven that point countless times over. But what can you do?

  1. If you value what we are doing and want to protect your water, you can help by submitting this document to IDEM. This is your expected role in the public comment period and exercises your right as citizens to call for a proper public hearing and a transparent investigation. It is not a pointless petition. About 30 more signed documents are still needed to force the hearing, and time is running out.
  2. Also, you can help support the citizen action. The site is private property, which is under the exclusive authority of local government has exclusive authority – IDEM’s authority is limited to enforcing regulation. Only local government can assert the level of direct control to halt a threat to public safety – this includes the testing which is so desperately needed. When local officials fail or refuse to take those actions, citizens can enforce those actions through a court filing. I have invested everything that I have to do what your elected officials will not – their jobs. But I have nothing left to give, so at this point, it is up to the community whether those demands are met. Every contribution is significant.
  3. If nothing else, you can stand up and be heard. If you support a sports team, you don’t cheer from behind the bleachers and hope no one sees you. This is not a political issue simply because politicians are standing in the way for their own benefit, at your expense. Water is a fundamental right. If you won’t stand up yourselves that simply because a politician is involved, exactly where do you draw the line?

If this page hasn’t motivated you to do one of those three things, then make note of every name in this document. Those will be the ones to hold responsible for attempting to convince you that this information was in somehow in dispute. Misleading the public about a threat to public safety is a federal crime – even if the reason is because they were too negligent to get their facts straight before speaking.


Although all of our work is technically consulting, Verdant offers in-depth treatment of all chemistry-related subject matter, including:

  • Laboratory Instrumentation
  • Biochemistry & Medical Science
  • Chemical Analysis
  • Materials Science & Compatibility
  • Hazardous Materials
  • Regulatory Affairs

Verdant has in-house AAS, HPLC, UV-Vis, & wet-bench capabilities in addition to affordable agreements with off-site facilities to round out full-service analytical capabilities.

If you would like to request consultation please reach out via any contact method in the sidebar.

UV-Vis Spectrometry – Troubleshooting & DIY

UV-Vis Spectrometry

UV-Vis spectrometry is a simple, but sensitive technique that’s most often used to quantify, and less commonly used to identify. The concept is straightforward: light goes in, and less light comes out. Spectrophotometry is so attractive because of the technique’s sensitivity: its detection is linear across three orders of magnitude. Nearly any sample concentration can be determined by choosing an appropriate dilution. By applying the Beer-Lambert law, analysts can quantify the amount of a chemical present in a sample with very high precision.

Beer Lambert Law © VerdantThe Beer-Lambert Law

By measuring the amount of light that didn’t make it through (absorbance, A). Every chemical has a unique physical property called an extinction coefficient, which is a measure of how much light it absorbs (ε = color intensity in solution). This value is specific to a given wavelength, so this is sometimes written with a subscript, such as ε690. When you combine that information with the amount of sample the light passed through (l – the path length), you can determine an exact concentration (c).

Important! Wavelengths are usually chosen by the absorbance maximum (highest peak), but in advanced cases, different wavelengths can be used to bring the sample’s absorption into the linear range without dilution.

What’s the difference between spectrometry and spectrophotometry?

Not much – the difference is what you do with the information. Spectrometry is evaluating a profile of electromagnetic radiation for a compound across an entire spectrum. That can be an entire range, such as all UV & visible light, or it can be a limited subset like the near infrared. A UV-Vis spectrum can be used to identify compounds in a sample, or tell inorganic chemists about the nature of the bonds in a complex. Spectrometry applies to any part of the entire electromagnetic spectrum.

Spectrophotometry deals with measuring the amount of light being transmitted or absorbed at any point along that spectrum. That enables an analyst to to determine the concentration within a sample, and provides researchers with important information about a sample’s physical properties.

Important! Light is measured in moles of photons. Absorbance is a unitless measurement because the moles cancel during calculation – another name for ϵ is the molar absorption coefficient.

Proper Maintenance


Troubleshooting UV-Vis Spectrometry

I don’t see any peaks! (Flat Spectrum)

First, ensure that your lamps are turned on, warmed up, emitting light, and that the light path to the detector is not blocked.

If your UV-Vis uses a monochromator instead of a polychromator & photodiode array, it’s possible that the motor has failed or become stuck. If this is the case you will have a flat graph as it reads every data point to be the same, but it will be offset from the baseline to some extent when running a sample compared to a blank. To confirm, compare a blank to a sample covered in electrical tape, which be read as a sample with a saturated absorbance signal. Motors fail often are not too hard to replace, but this will be a precision servo. Replacing it in the proper alignment can be challenging.

If you can visibly confirm that your lamps are turned on and working, then you may have a problem with the detector. If you have a working monochromator, it’s reasonable to expect that a single photodiode may have failed. But in the case of a polychromator and photodiode array, it’s very unlikely that an entire array failed at once. Trace the wiring inside the instrument and to the computer, checking for loose cables, unseated connectors, or broken/sharply bent wires.

I don’t see any peaks! (Noisy Spectrum)


My spectrum is flat on the left or right side! (Spectrum Trails Off Flatly)

If your spectrum begins to flatten toward the left or right side, it means you have a dying lamp. If it’s toward the left side, in the UV range (~200 nm), then it’s your deuterium lamp. If it’s to the right side, in the red light range (~700 nm), then it’s your tungsten lamp. Both lamps emit overlapping wavelengths of light in the center of the spectrum, so that’s why you’ll only see dead zones in the far ends are specific to each lamp.

My spectrum is flat on the left side! (Noisy Left Side)

You’re most likely using the wrong type of cuvette. Plastic cuvettes won’t work because most polymers are linked by a carbon-carbon single bond, which absorbs strongly in the UV range. Fused quartz cuvettes are used because it’s one of the few substances which allows ultraviolet light to pass absorbs ultraviolet light.



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Infrared Spectrometry (IR/ATR) – Troubleshooting & DIY

Troubleshooting Infrared Spectrometry (IR/ATR)

Developments in ATR have caused it to become the most common form of IR spectroscopy over the past two decades. Its unparalleled convenience has led to widespread use in preliminary and routine analyses. But the deceptive simplicity of ATR can lead to some common, but unexpected issues.

Although ATR is attractive because it requires little to no sample prep, be aware that the prep work has just been shifted to the instrument itself – and is still as important as ever. Since your sample’s spectrum will only be as good as your contact with the crystal – your first step will be proper cleaning.

Prep Work & Preventative Maintenance

The ATR crystal should be cleaned thoroughly at the beginning of every work day, and after any analyses which might leave a residue. These can include foods, oily products, plasticizers, and objects exposed to the outdoors. First, wipe the lens and surrounding area using lint-free optic lens cleaning paper, such as Kimwipes. Next, remove any leftover residue with a fresh wipe soaked in an organic solvent such as methanol or MEK (the higher the volatility, the better).

Important!  Water should never be used! Although some crystals can tolerate exposure, there’s always a better solvent choice. It has high IR absorption, evaporates slowly, and avoiding water altogether will remove the potential for expensive mistakes. Acetone is suitable, but should be avoided – stray droplets will mar the instrument’s plastic surfaces.

After cleaning the surface with a solvent, it is very important to allow for full evaporation before taking a background. If the solvent doesn’t fully evaporate first, the spectrum will be skewed by the solvent peaks. If the ATR window is under an argon or helium gas purge, the close the gas valve and open the chamber to room air. Nitrogen purges can remain in place and will be fully evaporated after ten minutes. Evaporation in standard room air takes approximately 20 minutes. Permanently enclosed chambers require even longer.

Important!  Solvent evaporation depends on its attraction to molecules in the air. Inert purge gases like helium and argon simply don’t have the intermolecular attraction to carry the solvent away at a reasonable pace.

Dry and powdered samples should be cleaned after every use by wiping the area thoroughly with lens cleaning paper. Follow this by using a non-abrasive powder brush to dislodge any stubborn particles which may still be caked onto the sides of the crystal. Once the instrument is clean, double check your method to ensure that it’s set up properly for your source and ATR window. Ensure that you have a reasonable scan resolution and count, and take a new background. Then perform a scan of a standard such as PS, PTFE, or LDPE film. Compare this to a reference spectrum.

Important! If your peaks are shifted from the correct wavenumber, your instrument could need realigned or recalibrated. If your peaks are growing weaker than your reference spectrum, your source could be aging; the ATR window might need polished/replaced; or the clamp could be giving poor contact with the window.

I’ve got this weird band around 3500 cm^-1 that keeps creeping in every few days. I can’t figure it out!

Important! That’s part of the water spectrum – you’re seeing the change in humidity. Controlling the environmental conditions in your lab is an topic unto itself, which we’ve explained in detail here.

If your IR is cooled or purged by gas from a liquid nitrogen tank, condensation is also a possibility.

My spectra used to be smooth but now they’re jagged and I don’t know what happened!

Important! Most likely, the scan resolution was changed somehow. This can happen when a different method gets loaded. Most labs run their instruments at low resolutions for smooth graphs with easily identifiable peaks. Higher resolutions will suffer a signal-to-noise ratio drop. To maintain the same quality in resolution half as wide, you need to double your scan number (and 1/4 width requires 4x the number of scans; and so on). This quickly leads to long sample collection times for instruments which aren’t designed for high-res data collection.

What’s a sine wave doing in my data?

Important! Your sample is probably reflective. If the problem persists through different samples, then a mirror within the instrument may have fallen out of position.

I’m getting results that don’t make any sense!

Important! Spectrum database search software often gives questionable results, especially when analyzing composite / proprietary samples. Create a table of molecular features from the peaks and bands; and supplement your analysis with data from other instruments when needed.

I’ve got a massive backlog of samples to identify or compare. Have you got any tricks that can help me? 

Important!  Try rapid qualitative analysis to quickly identify samples of interest:

First, configure your IR method with a resolution and scan count that produces an acceptable spectrum in less than five seconds. Next, clean the window with solvent, wait 60 seconds, and immediately perform a background. Then run each sample exactly 60 seconds after cleaning the previous residue from the window. The residual solvent peaks will be suppressed by the background. Repeat samples of interest using proper techniques, as these spectra will not be suitable for publication, consumer goods, or physical evidence.


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Thermogravimetric Analysis (TGA/DTA) – Troubleshooting & DIY

Troubleshooting Thermogravimetric Analysis / Differential Thermal Analysis (TGA/DTA)

Important! This page is under active construction – please check back in a few days. Important!



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Differential Scanning Calorimetry (DSC) – Troubleshooting & DIY

Troubleshooting Differential Scanning Calorimetry (DSC)

Important! This page is under active construction – please check back in a few days. Important!



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Liquid Chromatography & HPLC – Troubleshooting & DIY

Liquid Chromatography & HPLC

Liquid chromatography is one of the most common processes in science. You may you know it as HPLC, and use it for analysis. Or perhaps you know it by a trade name, such as CombiFlash, and use it for separation of products. Whatever the situation, it’s rare to find a lab that doesn’t employ some form of liquid chromatography. In a sentence, LC involves passing a liquid through a tube of granular material that will interact with the samples dissolved within the liquid. The tube is called a column, and its solid contents are the stationary phase. The liquid that passes through the column is the mobile phase, called an eluent or solvent. The interactions between the stationary and the mobile phase happen at the molecular level – but (ideally) there is no reaction or filtration taking place.

LC Column

LC columns are classified as either normal or reversed phase. A normal stationary phase is neutralized silica gel (essentially high purity sand with its pH adjusted to around 7). Other varieties include silicate polymer gels bound to other polar groups, such as nitros or diols. Reversed phase consists of a hydrocarbon gel categorized by its chain length or monomeric sidegroup (C18, C8, phenyl, and so on). Column type is your first consideration in LC, and it will mainly be influenced by your sample’s molecular properties.

  • Reversed Phase (RP – Nonpolar): Hydrocarbon or aromatic polymer.
    • Interacts with non-polar compounds, slowing them down (longer retention time).
    • The most polar compound elutes first; most non-polar compound elutes last.
  • Normal Phase (NP – Polar): Neutralized silica or silicate polymer with polar side-group.
    • Interacts with polar compounds, slowing them down (longer retention time).
    • Most non-polar compound elutes first; most polar compound elutes last.
  • Special Types
    • Ion Exchange: Polymer gel with ionized side-groups. Reacts with specific ions in sample to quantify or purify.
    • Size Exclusion: Dextran polymer gel network. Hinders sample passage to separate compounds by molecular weight.

Important!  Polymers are less physically stable than silica-bonded columns. Always check your method against the maximum pressure specifications of the column.

Eluent (Solvent)

Your mobile phase selection will depend on your sample composition and available columns. Solvent quality is extremely important for LC. Impurities accumulate on the column and impede flow. Dissolved gases can lead to measurement error if not removed.

Protic solvents normally involve the use of a buffer solution to maintain the column at optimal pH, but these pose a risk to the instrument itself. Since salts and ionic solutions are corrosive, these must be purged from the system when not in use.

Important!  Never transition directly from a buffered solvent to a storage solution such as acetonitrile! Always flush buffers with water or another protic solvent first! Otherwise the salts will precipitate into the tubing or column fittings blocking flow and causing localized corrosion.

Verdant is an industry leader in solvent recovery technology. Recycling used solvent is a key focus of industrial sustainability efforts – and it’s also a great way to reduce operating costs. If you’re interested in learning about your options, ask us how we can help.

Flow Rate

Your instrument’s flow rate affects the pressure within the system. Your flow rates will typically fall within a range varying on the order of milliliters per minute (mL/min). Your flow rate selection will be influenced by your column dimensions, pore size, stationary phase composition, and solvent viscosity.

Data Sampling Rate

If your LC has a variable data sampling rate, faster is better – up to a point. If your sampling rate is too low, narrow peaks will tend to clip – meaning you’ll miss the tip of the peak and get an inaccurate reading. Set your data sampling rate to 40 Hz as a starting point, and then raise it as high as you can without increasing baseline noise.

Derivatization / Internal Standardization

Derivatization is an excellent option when you have trouble with solubility, detection ranges, or peak shape. By subjecting the sample to a chemical reaction, you can change the chemical structure into a derivative that’s better suited for analysis. It can also be used to work with a more limited set of  supplies by increasing sample compatibility with your available columns and solvents. There are more reactions than we could ever list here – entire books have been filled with the possibilities. But don’t worry, because we have those books! Contact us for assistance if you need help with this technique.

Internal standardization is a technique that’s better suited to UV detectors than LC-MS. This can help you to determine something elusive that can’t normally be detected with UV – such as a sample and solvent pair that absorb in the same range. By spiking your sample with a compound which absorbs outside of that range, you can quantify concentrations much more accurately.

Troubleshooting Liquid Chromatography & HPLC

I have a noisy baseline! (General Issues)

A noisy baseline is a common symptom with several different potential sources, which can make troubleshooting very time consuming. You might have a leak. The column could be contaminated or degrading. You could have a low signal to noise ratio brought on by solvent impurities, or a data acquisition rate that’s too high for your method. If the noise is periodic, or rhythmic like a wave, then it could be a failing pump or pulse dampener. If the noise is spiky and appears irregularly, it there could be bubbles within the system, or the detector lamp could be flickering/failing. If your instrument isn’t isolated on a power filter with ferrite chokes on the wires, it could also be caused by electrical noise from other devices within the lab.

My baseline won’t stay still! (Baseline Drift)

If your baseline repeatedly drifts in the same direction over the course of every gradient run, then your column is contaminated (if you normally run isocratic, you can run a gradient to see whether this is the case). Ensure that you’re taking adequate column protection measures, then clean or replace your column.

If you’ve ruled out column contamination, or if your baseline is drifting randomly or steadily in a particular direction over the course of multiple runs, it may be time to replace your detector lamp.

My peaks keep showing up earlier/later every time I run a sample! (Retention Creep)

As your column ages, it will be less effective at interacting with the sample, and the retention time will slowly get shorter. If this effect becomes significant enough to be noticeable between runs, check that you’re adequately maintaining the column’s pH between runs. If so, then it’s just time to change the column.

If your retention time is getting longer with each run, remember that LC leaks cause late peaks. If you can see the problem worsening, then you likely have a part wearing out and physically falling apart, which usually be accompanied by other erratic findings. You’ll most likely find the offending part, but LC is a sensitive technique, so don’t be surprised if the flaws aren’t visible to the naked eye. When in doubt, replace any parts which have been in service long enough to be at risk.

If your retention time is changing erratically, there is probably a bubble entering the system at injection time, or solvent cavitation occurring at the pumps. Ensure that your sample solvent and mobile phase are being adequately degassed, and check the inlet.

My peaks have peaks! (Split Peaks)

This means your sample is getting hung up on something. First, confirm that your sample and its solvent are compatible with your entire mobile phase (both solvents if you’re running a gradient). If compatibility checks out, then there is something in the way. This can either be a solid contaminant, or a bubble trapped in a component. Careful inspection will be necessary to determine which.

My peaks aren’t sharp enough to quantify! (Peak Tailing / Fronting)

This usually indicates a problem with the column caused by improper use. First, rule out whether your sample volume is overloading your column. Then check the column for voids, degradation, or channeling (all ways of saying: gaps within the column packing). For troubleshooting this issue, the simplest first step will be to replace the column and guard. Before running another sample, check for flawed processes. Confirm that the method is not exceeding the temperature limit of the column packing. Ensure that the column’s pH is being maintained correctly. Verify that the column is being properly stored between uses. Consider implementing a log recording the dates the guard columns are replaced, and increase the frequency if necessary.

If the problem is unique to particular samples, or certain portions of the chromatogram, you’re most likely seeing multiple components elute together, and should adjust the method to secure better separation.

My peaks are too wide! (Column Capacity)

Issues with peak width are mainly symptoms of sample volume. If your peaks are too broad, your column is most likely too small for your sample size, and is being overloaded. This is especially true for complex samples – your column interacts with everything being eluted, not just your sample. Ensure that you’re factoring the entire sample into column size determinations. If you’re certain that isn’t the case, first make sure your fittings are secure and that your target pressure is being reached. Then try slowing your gradient transition rate down to allow for a slower elution time.

My peaks are running together! (Poor Resolution)

This is usually a sign that it’s time to replace your guard column or filter, particularly if you’re noticing that pressures are beginning to rise. This is because poorly soluble contaminants tend to build up at the front of the column and get stuck.

My analyte isn’t showing up! (Missing Peak)

One possibility is that your analyte isn’t compatible with your solvent or column choice. This can include insolubility, UV absorbance masking, or samples that interact heavily with the column.

Another possibility that the sample is too dilute. A UV detector is linear across 4 orders of magnitude (104, or 10,000x concentration difference), so try increasing the concentration if the dilution factor is within your control.

Nothing is showing up at all! (No Peaks)

This could be an issue with your detectors or a wiring fault preventing communication. If you see noise in the baseline, the issue is probably not a loose connection or faulty wiring. Verify that your detector wavelength is set to a value that’s compatible with your solvent & analyte, and confirm that the connected solvent is what you intended to use. Check the signal gain and attenuation to ensure that your signal isn’t being suppressed into the baseline. Next check and re-zero or replace your lamp. If the problem still persists, then your detectors may be at fault.

I see peaks I don’t expect / the same peaks every run! (Ghost Peaks)

First, identify your ghost peaks by running your gradient method without any analyte. You can minimize ghost peaks by using HPLC grade solvents, and degassing, filtering, or using purification/water removal technologies.

Next, identify any injection issues by injecting a blank sample. Problems linked to injection indicate a mechanical part failure. You may have a poor seal that’s leaking, or you may have pump seals or injection rotors breaking down.

If your ghost peak is inconsistent, you might have a late bloomer in your sample. You can check for this by running your last sample and doubling the method time. The best thing you can do is to flush your injector between samples, and incorporate a “Solvent B” purge into the end of your method.

There’s something wrong with this LC Injection Syringe!

Even carefully maintained and properly used syringes wear out quickly with normal use, so it’s best to consider your syringes as consumables. Injection syringes are extremely fragile, and prone to failure at the slightest misuse. LC can involve corrosive liquids which can jam up a syringe pump within a few exposures.

Proper cleaning includes flushing the syringe with an appropriate solvent after every sample. Follow this with water and several acetone rinses, and then place the syringe back into its case.

We recommend that you always have spares on-hand. Replacement parts can be helpful, but undetectable flaws can make it difficult to change them without accidental damage to the new parts. It doesn’t take many bent replacements before it becomes cheaper and less frustrating to simply have an extra.

I heard you can regenerate a used column. How does that work?

As you run samples and solvents through your column, it will become less effective. While it is technically possible to regenerate a column, it isn’t always helpful to try. So before we delve into the process, let’s take a look some situations where you probably shouldn’t bother:

:(  If you’ve run samples with no filter or guard column
:(  If the column has already been regenerated several times
:(  If the column’s connections or fittings appear visibly worn
:(  If the column’s packing has begun to ooze out or channel (gaps within the material)

If any of those conditions are true, then regenerating the column won’t be your best option. Column regeneration involves the use of several different solvents which your lab may not carry – this can be a large initial expense, take up valuable lab space, and add to the regulatory overhead. The potential savings may not be worth the time investment for busier labs.

Important!  If your lab typically runs samples of unknown identity, your components probably have very short lifespans. But this doesn’t have to be the case! You can safeguard your column by pre-filtering your analyte. A standard vacuum filtration through a Nylon 66 membrane filter will remove anything that would get trapped on the column or in your instrument fittings. There’s no need to worry about sample loss, because anything trapped by this filter wouldn’t have been suitable for LC analysis in the first place. You can also pre-filter your solvents if you have concerns over their purity.

It’s also important to have a realistic expectation of what column regeneration can offer. When done properly, it will extend your column’s useful life and remove ghost peaks, but it won’t bring your column back to 100%. A regenerated column is like a tuned-up used car: it may run perfectly fine, but there will always be an increased of developing problems.

The table below provides the steps for the most commonly used columns. Different processes are required for special columns such as zirconia, or columns used for proteins and other biological samples. You also can design a customized process suited for the solvents and columns used within your lab.

Regeneration Processes for Silicate Columns

Column VolumesNormal PhaseReverse PhaseIon Exchange
20Hexane60 °C DI Water60 °C DI Water
20Methylene ChlorideAcetonitrileAcetonitrile
2060 °C DI WaterHeptaneMethylene Chloride
20Mobile Phase/Solvent AMobile Phase/Solvent AMobile Phase

Important! Hexane can be substituted for any HPLC grade hydrocarbon solvent. Isopropanol can be substituted with any anhydrous, HPLC grade alcohol, but it is the best transition solvent, but it is very viscous and should be run at a moderate flow rate.

Important! If your contaminants are metallic, these can be removed by including ETDA in the DI water pass.

Important! We don’t recommend “all in one” column regeneration mixtures, because no mixture of solvents can properly treat the column packing in one step.

Column volumes are the number of times the void volume for your column must completely transit the column to achieve the intended result. In plain english: For every milliliter per minute of flow rate (r), a full equilibration will take twenty times your column’s void volume (v). In an equation: 20 × (v mL) × (r mL/min) = # of mins.

The void volumes for most standard column sizes are given in the table below.

HPLC Column Void Volume (0.70 Average Pore Volume)

Column Size (mm x mm)Void Volume (mL)
300 x 50412.33
300 x 2172.74
300 x 1016.50
300 x 7.810.03
300 x 4.63.49
300 x 2.10.73
300 x 1.00.17
250 x 50343.61
250 x 2160.61
250 x 1013.75
250 x 7.88.36
250 x 4.62.91
250 x 2.10.61
250 x 1.00.14
150 x 50206.17
150 x 2136.37
150 x 108.25
150 x 7.85.02
150 x 4.61.75
150 x 2.10.36
150 x 1.00.08
125 x 50171.81
125 x 2130.31
125 x 106.87
125 x 7.84.18
125 x 4.61.45
125 x 2.10.30
125 x 1.00.07
100 x 50137.44
100 x 2124.25
100 x 105.50
100 x 7.83.35
100 x 4.61.16
100 x 2.10.24
100 x 1.00.06
50 x 5068.72
50 x 2112.12
50 x 102.75
50 x 7.81.67
50 x 4.60.58
50 x 2.10.12
50 x 1.00.03
30 x 5041.23
30 x 217.27
30 x 101.65
30 x 7.81.00
30 x 4.60.35
30 x 2.10.07
30 x 1.00.02
15 x 5020.62
15 x 213.64
15 x 100.82
15 x 7.80.50
15 x 4.60.17
15 x 2.10.04
15 x 1.00.01

If yours isn’t listed, you can determine its void volume for your column by calculating its volume and multiplying it by the average pore volume (usually 0.70, often 0.50). Convert all column dimensions to centimeters to get an answer directly in mL (1 cubic centimeter ≈ 1 milliliter), and divide the column’s inner diameter by 2 to get the radius!  v0 mL = 0.7 × π × l cm × (r cm)².

Important! Several manufacturers have copied mistakes from each others’ materials, leading to widespread confusion about void volumes. The volume of a cylinder is calculated from its radius squared – don’t square the diameter!

As always, we encourage you to contact us if you need help.


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Gas Chromatography & GC-MS – Troubleshooting & DIY

Optimizing Gas Chromatography & GC-MS

GC-MS has become the gold standard for routine chemical analysis and definitive identification. But it has reputation as a time consuming technique, and lab productivity is commonly bottle-necked by the GC. Fortunately, you don’t need to purchase a second GC to increase your throughput, because there are several ways to speed things up.

Optimizing your GC method can save you hours each day, so it’s important for your lab to get the most out of your equipment. A stock GC configuration with a default method can take 40 to 60 minutes. But a fifteen minute run-time is a realistic goal for most labs.

Labs that analyze the same few compounds every day – like production labs – will be nearer to ten minutes. Labs which only perform analyses within the same category – such as research labs – will be closer to fifteen minutes. Labs which need to cover a broad range of possibilities – typically forensics labs – will have the longest times, but even these should complete in under twenty minutes.

Now that you know what’s possible, let’s talk about how to get there!

Carrier Gas

The three main choices of carrier gas are helium, nitrogen, and hydrogen. Each choice has certain advantages and disadvantages, but the main points to consider are cost, safety, effectiveness, and speed.

Nitrogen is the most commonly used gas. As the most abundant gas in the atmosphere, Nitrogen’s main advantage is that it’s the cheapest carrier gas. Its biggest disadvantage is speed, so it tends to work best in labs where the GC sees only occasional use but doesn’t run constantly. That slow pace is the reason nitrogen has the best column efficiency, so it can be a good choice for tough separations – but you can achieve the same result by optimizing other components. So when the lab-work is being is held up at the GC, the first thing you consider should be switching to a different carrier gas.

Of the three gases, Hydrogen offers the greatest speed advantage. It comes with a reasonable cost, and its physical properties make it well-suited for use across a wide range of speeds, which gives it greater flexibility. Hydrogen can function well equally well anywhere from 20 to 80 cm/s. By comparison, nitrogen’s column efficiency drops off sharply at any velocity except 10 cm/s. This versatility allows for the fastest separation of many different compounds with methods optimized for the target analyte. Hydrogen easily stands out as the best overall choice for a carrier gas, but its primary disadvantages are safety concerns.

Important! Hydrogen is a widely-used carrier gas with virtually no risk to trained professionals when properly implemented. But proper implementation does require an initial investment in specialized equipment. The greatest risk is posed by using a tank of compressed hydrogen. By opting for a hydrogen generator, the gas is never pressurized and the risk of self-ignition is removed. The remainder of the risk can be mitigated by using a nitrogen purge or hydrogen detector to guard against leaks.

Important!Important! We advise against hydrogen as a carrier gas in academic labs where introductory training occurs with limited supervision.

Helium represents something of a compromise between nitrogen and hydrogen. It has a significant speed advantage over nitrogen; it’s almost as versatile as hydrogen; and as a noble gas, it’s the least reactive. Helium offers a number of advantages over nitrogen, without needing hydrogen’s risk management or special equipment. Its most significant disadvantage is cost: helium is fairly expensive due to its high demand.

Important!  A note on helium as a resource, as there has been some misplaced concern about “depleting” the planet’s helium supply – it’s not possible.
As a product of abundant underground radioactive alpha decay, helium accumulates in pockets which replenish themselves (unlike other gases). It then escapes the planet’s gravity at a constant rate due to its low mass, so the earth will continue to produce and lose helium at about the same rate for millions of years whether we use it or not.
That means the supply of helium is not a depleting well whose bottom draws ever nearer. The most accurate analogy would be a flowing river from which we can draw a steady, but finite amount.

Flow Rate

Your flow rate can be controlled in two modes: constant flow or constant pressure. We recommend constant flow, because constant pressure leads to wide variations in flow, and most of calculations in GC are based on flow rate. Each carrier gas can operate within a specific range of velocities without losing column efficiency.

Column efficiency is a measure of how much benefit you’re getting out of the column. Think of it like this – if you blast your carrier gas through the column, the molecules will be travelling too quickly to interact with the column. Those interactions are responsible for separation, so your peaks will be closer together than you’d expect from just shortening the run.

Nitrogen gas has the best column efficiency between 10 and 15 cm/s, reaching a maximum at about 12 cm/s. Helium’s optimum column efficiency ranges from 15 to 40 cm/s, while peaking at 20 cm/s. Hydrogen has the largest optimum range, spanning 20 to 70 cm/s, with best results at about 40cm/s.

GC Column

Choosing a column might seem complicated, but it’s really no different than the experience you might have when buying toothpaste. There seems to be a staggering number of choices! But once you cut past all of the fluff, you discover that they’re all just slight variations on two or three products made by the same company. So we’re going to make the decision as straightforward as possible, because if you wanted information overload, you’d probably be reading their product sheets instead.

First, let’s choose a stationary phase by determining whether your samples are normally polar or nonpolar.

  • Nonpolar: Use a polydimethylsiloxane (PDMS) column
  • Polar: Use a polyethylene glycol (PEG) column
  • Somewhere in between: Use a polyethylene glycol (PEG) column
  • Combination / unknown: Use a 50% phenyl column
  • Quant only, no separation: Choose the opposite of your sample (faster analysis)

Next, we can turn our attention to the film thickness. If your sample identity and concentration are usually unknown to you, choose a thicker film (about 1 µm). You’ll gain better separation and a greater tolerance for high concentration samples at a slight cost in speed. If you know your analytes and already have good separation, shorten your run times with a thinner film (about 0.1 to 0.25 µm).

A 0.25 mm inner diameter is ideal for most labs. Deviating from this without good reason can introduce problems.

A standard column length is 30 meters. A longer column will give you better separation, but slow your analysis times. If your configuration already has a good separation efficiency, reduce your run times by shortening your column. If you’re not familiar with column cutting, ThermoFisher has an excellent guide.


As the GC’s temperature rises, more components of the sample will enter the gas phase and travel down the column. If you’re not getting enough separation, a temperature ramp can introduce sample components more gradually. Ramps can also be used to sharpen peaks for better quantification. But keep in mind that molecules can become unstable and break apart if the temperature is too high. That also includes your column coatings, so always check its specifications before raising your oven temperature.

Raising the temperature beyond your sample’s thermal stability will cause it to degrade, and molecules that are too large to enter the gas phase directly will only appear as fragments. It’s important to recognize this when it occurs to prevent making false identifications. Although thermal degradation will make any peak integration meaningless,  with enough experience you’ll be able to identify the parent molecule from the puzzle pieces. The next technique – derivatization – is especially useful in these situations.

Derivatization / Internal Standardization

Sometimes you might encounter a sample that seems like it could almost run, but doesn’t. It may go undetected, fragment as described above, or leave molehills instead of mountains on your chromatograph. These aren’t issues that can be fixed by making adjustments to your GC, and this is where derivatization comes in. It picks up where other methods leave off: so long as your sample doesn’t run the risk of out-right damage to the instrument, you have options to make it viable.

By subjecting the sample to a chemical reaction, you can change the chemical structure into a derivative that’s better suited for analysis. But derivatization isn’t just for samples you can’t run – you can also use it to produce derivatives with shorter analysis times! There are more reactions than we could ever list here – entire books have been filled with the possibilities. Fortunately for you, we have those books! Contact us for assistance if you need help with this technique.

Internal standardization is a technique that’s better suited to GC than GC-MS. This can help you to determine something elusive that can’t normally be detected using FID – like the precise concentration of water in a set of serial dilutions. By spiking your water with a detectable compound (one which won’t interfere with further analysis), you can quantify concentrations much more accurately.

Sample Concentration

For both data quality and instrument longevity, you should aim to use the smallest detectable sample size possible. This is usually within the 1-100 ppm range, favoring the lower end. Dilution calculations are very straight-forward: m1v1=m2v– just remember to account for the dilution factor in your final analysis.

Some labs won’t always have total control over the concentration of the samples they receive, or even prior knowledge of their contents. This is normally the case in forensic labs. In these cases, other methods can estimate the sample concentrations before introducing it to the sensitive components of the GC. If you place a highly concentrated sample on an FT-IR or a UV-Vis, the worst that can happen is a saturated graph.

Concluding Points

While your GC offers plenty of room for optimization, all of these factors interact with one another – so take care to avoid making multiple changes at once. For example: while changing your carrier gas and adjusting your flow rate are both ways you can improve your performance, making both of those changes together can actually worsen your performance.

This guide is intended to help you get the biggest improvement possible in the shortest amount of time. But the reality is that bringing your GC to highest potential will require a bigger time investment, some careful planning, and plenty of calculations. But that’s what we’re here for, so don’t hesitate to contact us. If you’re the type who likes to dive into the details, we can provide you with the resources and guidance you need. If not, we can schedule a visit and get your GC running better than ever.


Troubleshooting Gas Chromatography & GC-MS

My peaks keep showing up later and later every time I run a sample! (Retention Creep)

You probably need to change your septum. Certain brands wear out very fast, so this can catch you off-guard after switching if you’re used to a more durable brand. If changing the septum doesn’t fix the issue, secure or replace other vulnerable seals. If that still doesn’t fix it, ensure that your gas pressure and oven temperatures are where they should be. Also ensure that the run is being started consistently every time.

My peaks aren’t sharp enough to quantify! (Peak Tailing / Fronting)

As long as your installation hasn’t changed recently, this usually indicates a problem with the sample itself. Your sample concentration might be too high for that compound, or the sample could have poor compatibility with the column. Try diluting the sample, derivatization, or changing the column.

My peaks are running together! (Poor separation)

Follow the GC Optimization guide on this page to learn how you can improve your peak resolution and run time.

My chromatograms trail up into an S shape at the end of the run! (Column Bleed)

If you start to notice column bleed, it generally means that you’re falling behind on your maintenance, so it won’t hurt to give your GC a full tune-up. First, bake out your column by running it at the flow rate maximum and isothermal temperature limit for about 20 minutes. Start by replacing your short-lived components (seals, septa, and o-rings), then change your gas filters and trim your column ends by a few cm. Reassemble everything with extra care, and double check for leaks. If the bleed still continues, then your column is just worn out and needs replaced.

My peaks have peaks! (Split Peaks)

This is usually a problem with injection or vaporization. If it’s happening consistently for multiple users, then check ensure that the injector port is reaching the correct temperature, and verify that your solvent is compatible with your column. If it’s more intermittent, try injecting a lower volume more slowly (1 ppm & 1 µL should  be your guideline). If this still doesn’t fix it, consider adding wool to the injection port. This increases the surface area and aids rapid dispersion and vaporization.

My analyte isn’t showing up! (Unsuitable Samples)

GC-MS is a powerful technique, but it does have limitations. A general guideline is: if you can’t smell it, you can’t run it. Samples with high molecular weights (such as a heavy oils) are also unsuitable. When a molecule is too heavy to vaporize, you’ll never see the full molecule on the chromatograph. You’ll only see fragments of its thermal degradation – and you’ll continue seeing them until the sample fully degrades.

Important! Salts, ionic solutions, and metals are absolutely out of the question!

There’s something wrong with this GC Injection Syringe!

Even carefully maintained and properly used syringes wear out quickly with normal use, so it’s best to consider your syringes as consumables. Injection syringes are extremely fragile, and prone to failure at the slightest misuse. Mildly corrosive samples can jam up a syringe pump in a matter of seconds when introduced to the high temperatures of the injection port.

Proper cleaning includes flushing the syringe with an appropriate solvent after every sample. Follow this with water and several acetone rinses, and then place the syringe back into its case.

We recommend that you always have spares on-hand. Replacement parts can be helpful, but undetectable flaws can make it difficult to change them without accidental damage to the new parts. It doesn’t take many bent replacements before it becomes cheaper and less frustrating to simply have an extra.


Is there something else that you think should be included on this page?

Let us know with a comment below!


Autoclaves – Troubleshooting & DIY

Troubleshooting your Autoclaves

Important! This page is under active construction – please check back in a few days. Important!



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