Archive for the ‘Miscellaneous’ Category

Electronic Cigarettes Part II: Solution Analysis – You don’t have an MS… no problem.

In the last e-cigarette blog we (Amanda, Colton, and me) showed you a quick proof of concept for analyzing the major constituents of e-juice. Working from that starting point, we realized that some labs may not have access to a GC-MS and/or some may only be interested in a very quick screening method for the nicotine content in e-juice. So…  that is exactly what we’re showing you today.

The table below contains all the specifics of interest for a rapid GC-FID screening method for nicotine in e-juice.

GC-FID Parameters D

We continue to use our thick film volatiles column, because the ultimate goal with e-smokes is to see what is in the vapor. Also, it is already doing an excellent job on the current application. So we simply bumped up our starting temp to 100 and now we have a 5 minute run (see below).

GC-FIDOkay… so there may be a little bit more. As we mentioned last time, we purchased some raw e-juice and analyzed it as is (i.e., straight from the refill bottle). Well since the last blog we have learned that the e-juice is extremely viscous. If you plan to analyze the e-juice raw (i.e., without any dilutions) you will have to set up your injector appropriately (see below). We suggest you include at least one sample wash; lower the sample wash speed down to ~30 µL/min; and you may also want to add in a viscosity delay. Close observation of your autosampler syringe coupled with a little experimentation will get you to where you need.

GC-FID B

Alternatively, you could just simply dilute your e-juice, which is ultimately what we suggest. If you want to have quantitative nicotine results, clearly you will need to calibrate your instrument. So when you use our nicotine standard at 1,000 µg/mL you will realize that most of e-juice nicotine concentrations are well above this. So… a nice 100 fold dilution with methylene chloride (yes, methylene chloride and not methanol if you want to look at ethanol) will kill the following two birds with one stone: 1. you no longer have viscosity issues. 2. your concentrations fall nicely into your calibration curve.

Speaking of which… the aforementioned method calibrates fairly well [i.e., the correlation coefficient (r) (not the coefficient of determination (r²)) = 0.99562] from 1.6 x 10-2 to 1.0 mg/mL (see below). FYI – most e-juice nicotine concentrations are ~10 to 20 mg/mL for a 1.8% nicotine solution. Remember… we diluted by 100 fold, so we typically injected 0.1 to 0.2 mg/mL. Well within the aforementioned calibration curve.

E-Cigs CalibraitonSo… that’s enough about e-cigs for one week. But stay tuned for the next blog on electronic cigarettes.

Book Review: Echoes of Life: What Fossil Molecules Reveal about Earth History.

The year 1936 marks the beginning of organic geochemistry. It started with Alfred Treibs’ discovery of porphyrins in petroleum; compounds that closely resemble chlorophylls in plant matter. Another 25 years would pass before scientists recognized that these compounds, known as biomarkers, could reveal insights into the evolution of plants and animals spanning a time frame measured in billions of years.

The striking similarities between cholesterol and sterane.

The striking similarities between cholesterol and sterane.

Echoes of Life weaves a complex fabric of stories, peppered with personal details, that describe the emergence of analytical techniques; mainly GC-MS. The authors are a mix of organic geochemist, founding father of biomarker research and a marine chemist/novelist that draw on a variety of perspectives and experiences. Echoes of Life is a well written, digestible story rather than a textbook.  One of its enduring facets is the ability to eloquently describe the required transition of geochemist to analytical chemist; a necessity to crack the origins of oil. The book starts as a disjointed collection of stories from finding “life” on the moon to botanists studying leaf waxes. Using mass spectral interpretation it was evident that cholesterol could be found in oil in the modified form of steranes and hopanes. They were “stripped of their double bonds and oxygen containing functional groups reduced to their bare carbon skeletons.” The book follows researchers from around the world arriving at the same conclusion from various fields using different techniques. Described as, “a tribe of scattered chemists using the new technique of ‘coupled GC-MS’ and coming to the same conclusion.”

The Deep Sea Drilling Project (DSDP) revealed chemical traces of algae, zooplankton and microbes that proved to be a chemical chronicle of the last 150 million years. The keys to understanding the history of earth, its climate and life were locked in these biomarkers. For instance the degree of unsaturation in algae’s lipids increased systematically with an increase in temperature. Dialkyl ketones containing 37 to 39 carbon atoms were analyzed to determine the number of double bonds remaining. Combining age of sediment and dialkyl ketone data, scientists were able to estimate regional global temperatures.

Sterane and Hopane patterns (shaded areas) by GC-MS SIM using an Rxi-5Sil MS 30m x 0.25mm x 1.0µm film column.

Sterane and Hopane patterns in MC252 Crude (shaded areas) by GC-MS SIM using an Rxi-5Sil MS 30m x 0.25mm x 0.25µm film column.

The story is a combination of thousands of scientific papers, hundreds of interviews and many anecdotes as a mechanism for moving the story forward. Reflected in these pages is an insatiable curiosity that defines science. This book is a journey of discovery, the human spirit and the quest to understand our surroundings. It is a trip worth taking.

Echoes of Life: What Fossil Molecules Reveal about Earth History. Susan M. Gaines, Geoffrey Eglinton and Jurgen Rullkotter. Oxford University Press, 2008. 376 pp. (ISBN 9780195176193 cloth).

Check out Michelle’s work on oil identification: Fingerprinting Crude Oils and Tarballs using Biomarkers and Comprehensive Two-Dimensional Gas Chromatography

Petroleum Biomarkers and Tarballs at the 36th International Symposium on Capillary Chromatography and the 9th GCxGC Symposium

Gulf Oil Spill Blogs

http://blog.restek.com/?cat=3

 

Which LC column should I use for Method 8330B explosives analysis?

cropped 526

Over the years, Restek has run applications on a long list of columns for this analysis. It does require a primary and secondary column for analysis, since there is not one column that perfectly separates all compounds on the list simultaneously. Keep in mind that EPA Method 8330B allows for alternate columns versus the ones listed if you can demonstrate proficiency by presenting valid data that meets QC acceptance criteria as described in Method 8000. Our Innovations chemists have worked hard to make column selection easier for this and get you started in the right direction for optimization.

So far, we have determined optimal conditions for two pairs of columns that we recommend above all other combinations. For traditional HPLC systems with a 400 Bar pressure limit, we suggest using an Ultra C8 as the primary column and an Ultra Aromax as the secondary (confirmatory) column.

Here are chromatograms. For best resolution, please click on the chromatogram.:

 

cropped lc 526cropped lc 527

 

 

If you have a system that has a pressure limit of at least 600 Bar, we suggest our Raptor™ Biphenyl as the primary column and Raptor™ ARC-18 as the secondary column.

Here are chromatograms. Again, for best resolution, please click on the chromatogram:

cropped lc 530LC531

 

 

 

 

I hope this clarifies some things and gets you started in the right direction. Thank you for reading.

 

How Dirty Are You? Part 2…Pipet Bulbs…The Answer

Check out the first How Dirty Are You? blog about Parafilm.

The How Dirty Are You? pipet bulb blog showed some interesting data…mainly that I need to clean my pipet bulbs and periodically replace them. I am happy to report that I have changed my pipet bulb twice since and even do some solvent rinses.

The question I posed in the initial blog was about a high intensity peak found when a latex bulb was rinsed with acetonitrile. The question I asked was what type of common additive was responsible for producing such a high signal…

Was it a Dye, Antioxidant or UV Stabilizer?

Some people indicated that they thought it was a phthalate. This is a very good guess based on the numerous times phthalates appear in blank samples, but in this case the compound was identified as butylated hydroxytoluene (BHT).

BHT

 

BHT is an antioxidant compound that is used in everything from rubber to food, pharmaceuticals…even embalming fluid! This stuff is everywhere.

PHOTO: http://mywholefoodlife.com/2013/01/12/jenny-o-exposed/BHT food 2

 

BHT lotion 1

 

latex bulb cgram update

 

Freedom Industries Has Been Fined By OSHA

Freedom Industries, the company responsible for this January’s large MCHM spill in West Virginia, was fined $11,000 by OSHA. Read more at VICE News.

The OSHA fines only cover violations for endangering employee safety. Environmental fines may still be forthcoming.

Electronic Cigarettes Part I: Solution Analysis – What is in the “e-juice”?

Throughout this summer I have the pleasure of working with our intern, Colton Myers. The soon-to-be chemistry senior at Juniata College joined Restek for some practical laboratory experience. We wanted him to work on something “cool” and “interesting,” so what better project is there than electronic cigarettes?VapingYou do not have to look very hard to find someone “vaping” on an e-cig, so these things are definitely gaining traction. Despite their explosive popularity, we have only been able to scrape up a few published reports. In fact, a fairly exhaustive peer-reviewed literature search only turned up a couple of articles. So… needless to say Colton has now spent the past month working on the analysis of electronic cigarettes. As a starting point, we worked on the analysis of the “e-juice” only (note, this is a teaser for more to come later).

So we developed an analytical method for a quick screening of e-cig solutions. We utilized SOF and our approach was KISS (keep it simple, stupid). The table below contains all the specifics of interest:

E-Juice GC-MS ParametersAs a first pass, we tore open an e-cig; used 10 mL of methylene chloride to extract out the juice; concentrated the extract down to 1 mL; and here is what it looks like when using the above parameters:

E-Juice C-GramNow… the aforementioned approach was a simple, qualitative pass for determining what was in the e-juice. We did not use any surrogate standards; however, this could be easily done in the future. In fact, these results indicated that nicotine was ~35% of the total solution, which is a far cry off from the manufacturer’s claim of 1.8%. This we attributed to our extraction/concentration procedure, but this did not matter to us, because our next approach was to just purchase some e-juice straight up (that’s right, keep up with the lingo) and analyze the raw solution, thereby cutting out any errors associated with extraction/concentration, etc… And here is what we got for a raw (i.e., unprocessed) 1.8% nicotine solution:

E-Juice ResultsSo what does all this mean? Well… our method worked well for the rapid analysis of the major electronic cigarette components and our analyte list matches up “fairly” well with what the manufacturer lists on their website. I say fairly because they do not list ethanol, but we clearly found it; and yes, we ran blanks to ensure this was not a contamination issue (hence, how we found water as a “contaminant”). In addition, according to our results this sample is slightly (yes, not orders of magnitude) off from the manufacturer’s claim of 1.8% nicotine in solution. However, our observation is consistent with what Trehy et al. observed in 2011 (“the nicotine content labeling was not accurate with some manufacturers”). Perhaps this is well within the manufacturer’s tolerances or maybe they do not actually test any of this, because as of now not much of the e-cig business is regulated.

Now… you may be asking “why the thick film volatiles column?”…. well I am glad you asked. Remember my teaser from before? See no one actually drinks, bathes in, or injects (I hope) the e-juice. They “vape” it (i.e., draw the solution over an atomizer and inhale the resulting vapor). So honestly, from my point of view I could really care less about what is in the raw e-cigarette solution. I am more interested in what is found in the vapor. So can you take a guess as to what may be found in later parts of this series? Stay tuned…

 

Trehy, M.L.; Ye, W.; Hadwiger, M.E.; Moore, T.W.; Allgire, J.F.; Woodruff, J.T.; Ahadi, S.S.; Black, J.C.C; Westenberger, B.J. Analysis of electrongic cigarette cartridges, refill solutions, and smoke for nicotine and nicotine related impurities. J. Lig. Chromatogr. Relat. Tech. 2011, 34, 1442-1458.

Flame Retardants on my Mind and on Your Electronics and Your Furniture and….

I recently returned from the Brominated Flame Retardant Workshop in Indianapolis, Indiana. Going to a conference that covers analytical, occurrence and fate, biological and toxicology really puts what Restek does and the products that we make into perspective. Being able to analyze flame retardants in biotic and abiotic matrices is only the first challenge. The analytical methodology and data is used to monitor the levels in humans and the environment, and that data is then used for toxicology studies. Finally, and hopefully, that data is used to form policy that will in turn protect the environment and human health. The BFR meeting covers each of these important links surrounding flame retardants and I always come home from that conference and think about the work that I do to hopefully help the analytical scientist, and the changes I can potentially make around my home and office to reduce exposure to flame retardants (and other persistent organic pollutants).

I enjoyed many of the presentations at the BFR workshop, but one in particular stood out because it is a real problem, but not one that I normally think about. Where do you send your old electronics? With the rapid pace of new technology there is now a rapid increase of electronics waste. Electronic waste (e-waste) recycling in concept is a good thing. We really don’t want all of that in our landfills and electronics contain many precious metals that can be re-used. However, as Li Li from The College of Environmental Sciences and Engineering, at Peking University presented, the process of recycling the e-waste is, in many cases, rudimentary at best. Much of our waste is being shipped to developing nations that use children for labor. The e-waste is being burned in open areas, often very close to where the working families are living. Burning the electronics and plastic casings that are coated with flame retardants and other chemicals creates a toxic smoke that contains lighter brominated diphenyl ether congeners (PentaBDE), dioxins and furans, mixed brominated and chlorinated dioxins and furans, polycyclic aromatic hydrocarbons and heavy metals (just to name a few).

 

 

Much of the e-waste recycling is done in or near residential homes and employs children to help sort and disassemble old electronics.

 

Toxic smoke containing heavy metals and many organic pollutants from burning electronics waste located in someone’s “backyard”.

SDS (MSDS) for VICI® Mat/Sen® Gas-Specific Purifier Modules

Once in a while we (tech service) get asked for a SDS (MSDS) for VICI® Mat/Sen® Gas-Specific Purifier Modules.  Even though we are not required to provide one with the product, sometimes customers need to know their contents.  Simply click on the links below of the appropriate purifier to obtain your SDS (MSDS).

Purifier

For the Helium, Hydrogen, and Nitrogen Purifier Module  Helium, Hydrogen, and Nitrogen Purifiers

For the Air Module   Air Purifier

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Here are a few other related links (if interested).

Contents inside your baseplate trap

Changes are coming to the MSDS; um, I mean the SDS

 

How Dirty Are You? Part 2…Pipet Bulbs…The Question

Check out the first How Dirty Are You? blog about Parafilm®.

This How Dirty Are You? blog is all about pipet bulbs. Our lab has 14 people and we have at least a few types of pipet bulbs for both borosilicate glass Pasteur pipets or volumetric pipets. I am sure this isn’t surprising to most of you but each person has their favorite type. Our facility only stocks one kind of pipet bulb so we have to order the other types that we like and this makes for some interesting negotiations. Right now, my colleague, Linx is my supplier for my favorite type of pipet bulb…which is the larger light blue one. Preferences for specific bulbs are strong and we have had many conversations about why we like a particular type. For example, Michelle Misselwitz likes the small black bulb because it helps her prevent pulling liquid into the bulb itself.pipet_choices

 

One of the goals of the original “How Dirty Are You?”’ project was to find contamination sources that are sometimes overlooked so we tested a few bulbs to see what was lurking inside. I tested the bulb that I had been using for some time, my lab mate Jason Thomas’s bulb and a general latex lab bulb with unknown history on how or if it had been used.

What we did

The inside walls and bottom of the bulb was rinsed continually with 400µL of acetonitrile for about 1 minute. Then one microliter of this was tested by GC-MS using generic testing parameters.

The results

Jason’s bulb looked just like the solvent blank! Very clean…My bulb was a different story. As you can see (blue trace), my bulb was filthy. I know some of this might be the different bulb material but Jason also told me that he periodically cleans his bulb with solvent. I think it is safe to say that this was not a practice I had been doing. The latex bulb (yellow trace) was not nearly as dirty as mine but there were some significant peaks.

julie and latex bulbs

 

I promptly retired that pipet bulb and placed it on my office bookshelf…I just couldn’t throw it out after so many months of service…and to this day it still sits there.

I promptly retired that pipet bulb and placed it on my office bookshelf…I just couldn’t throw it out after so many months of service…and to this day it still sits there.

 

I think what surprised me the most was the intensity of some of the peaks. Much of my work deals with trace level analysis, ppb level, so I was not accustomed to seeing such high levels. This figure below shows an overlay of chromatograms from my bulb (blue), the latex bulb (yellow) and a 5 ppm hydrocarbon standard (black). In many cases, peaks from my bulb are much larger than this 5 ppm level and even the general lab bulb shows a few peaks higher than the 5ppm level.

 

pipet overlay

 

Finally…Here is your question:

One thing I learned from this project is that there are compounds that are just about everywhere and this is the case with the largest peak of the general latex bulb…see starred peak below. So the question is…

A common additive for rubber was found in the latex bulbs. What type of compound was this?

  1. Dye
  2. Antioxidant
  3. UV Stabilizer

Post or email me your answer.

Email me with your answers and look for the data in my next blog.

 

starred latex bulb

 

 

 

 

Certified Reference Material Explained

Restek offers Certified Reference Material (CRM) for a wide variety of analytical methods. But what makes a reference material certified and are there different certifications available?

Let’s start with a brief overview of ISO accreditation. A company is first registered to standards such as ISO 9001:2008, which indicates they have an approved quality system in place that is actively followed. To earn accreditation to produce and test CRM, an independent ISO recognized accrediting body visits the site of a reference standard manufacturer; inspect the facility, and reviews established quality system implemented by the manufacturer. Accreditation is awarded when the auditor is satisfied strict criteria of Guide 34 and IEC 17025 are met. Also this accreditation is maintained by periodic visits by the accrediting body to ensure competence and impartiality. Restek has taken specific steps to achieve these goals.

Often, we are asked questions such as are these Reference Materials NIST traceable? Or a question of are these reference materials NIST certified? This may sound similar but they are two entirely different questions.

• Restek CRM’s are NIST traceable.
o Visit the FAQ section for details on this answer as well as other useful information on our Reference Standards.

• Restek CRM’s are not NIST certified. Only NIST can certify their Standard Reference Materials (SRM)

Another question on certification: Are your Reference Materials USP certified?

• Restek CRM’s are not USP certified. Only the USP can certify USP Certified Reference Materials.
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