Contaminants Everywhere

If you are processing environmental samples then you’ve probably dealt with contamination at some point.  If you haven’t, then you should be congratulated for creating the only laboratory on Earth that has ever been completely free of all sources of contamination!  There are many (in some cases, many many many) sources of contamination and the severity of your contamination issues can vary significantly depending on what types of samples you run, the cleanliness of your laboratory, the systems that are running, and the care with which samples are being collected, stored, prepared, run and disposed of.

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Question and Answer Time with EPA Method 8270

It is a regular occurrence for me to get various questions about EPA methods but recently I have had quite a few about EPA Method 8270 and I wanted to share them in case someone else has the same questions.    You can find a great summary of Method 8270 in this blog that one of my colleagues recently wrote – Extraction of Polyphenols in Tea with Lemon Juice.

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The Secret to Tackling Dirty Samples – Tips & Tricks for Filtering

Solid phase extraction is a powerful technique – it can be used to clean up the most challenging samples, and extract and preconcentrate hundreds of semivolatile organic compounds.  When performing the extraction, the goal is to get the entire sample to run through the extraction disk.  But in order to do that, the disk must have the chemical and physical capacity to handle your sample matrix.  If your disk becomes overwhelmed or clogs, you risk losing your sample and the chance to complete your extraction.

How do you prevent the disk from clogging?  Prefilters!

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Reducing the Headache of Challenging Emulsions

Have you ever opened a jar of olives and noticed the shimmering liquid floating on the surface?  Believe it or not, that liquid is actually residual oil that is given off by the olives themselves.  Since the oil is less dense than the aqueous solution that the olives are stored in (olive brine), it floats to the top of the jar.  This may not seem like a big concern to the typical olive consumer, however, olive manufacturers believe that too much oil in a jar is something that negatively affects the final product.  For this reason, olive companies are putting effort and resource into finding a way to quantify the amount of oil in their final product.

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What’s Your Grade?

“I’m usually ACS, although sometimes I’m Reagent.”

If you’re reading this and raising your eyebrows, you’ve never had, what I like to call, the “grade discussion.”  I don’t mean the discussion between high school or college students who are comparing grades after a big mid-term or final exam (although I used to do that too).  I mean the discussion over the solvent grade you use in your laboratory.

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Simplified BPA Analysis

Bisphenol A (BPA) is one of the most widely produced chemicals in the world – approximately 4 million metric tons annually.  In recent years, BPA has received a lot of negative attention.  In fact, I can’t remember the last time I saw a plastic item in the store that didn’t have a “BPA free” marking on it.  These labels are for good reason, though, as BPA has been found to produce negative hormonal effects within the body.  BPA is a chemical that mimics estrogen and disrupts the endocrine system, which can lead to developmental disorders, thyroid issues, diabetes and even reproductive organ cancers.  BPA is so prevalent because it has many uses in polymer chemistry.  First and foremost, BPA is used as a monomer in the production of polycarbonate, a very hard thermoplastic which has countless applications, including: water bottles, baby bottles, CDs, DVDs, eyeglass lenses and many more.

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Understanding SPE Retention Mechanisms

As a chemist, I’ve constantly stressed the importance of proper sample preparation.  Whether I’m diluting, digesting, preconcentrating, extracting, or performing a combination of these, sample preparation is the key to making my analysis a success, yet it’s often the most challenging part of my workflow.  Some of my preparation procedures are simply daunting – a series of challenging, time-consuming steps with multiple opportunities for error or cross-contamination.  On top of that is the multitude of parameters that must be selected.  Questions such as “what should the pH be?”, “which solvents should I use?” and “what should my sample volume be?” are a few of the many, many parameters that must be optimized.  When you look at all the opportunities for something to go wrong, sample preparation can seem very overwhelming.  While powerful, sample preparation becomes a lot less complicated when you understand the science behind what you’re trying to accomplish with this step.

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What does a thermistor do anyway?

It is easier to understand something when you know what the actual word means.  Thermistor is a portmanteau (yes, sometimes I do pay attention to linguistics) of the words thermal and resistor.  This means that when a thermistor is heated, its resistance is either increased or decreased based on the properties of that particular thermistor.  This property makes it very useful for many different applications all over the world.  But thermistors are most useful, at least from my perspective, when they’re used in automated solid phase extraction systems.

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Extraction of Polyphenols in Tea with Lemon Juice

For thousands of years, tea has been one of the most popular drinks around the world. Not only is tea delicious, it is also full of health benefits. Tea is an abundant source of antioxidants called polyphenols. One of these polyphenolic compounds, catechins, are found mostly in green tea. Catechins have been studied thoroughly and have been found to reduce free radical stress, they have also been found to be anti-inflammatory as well as potentially therapeutic for cancer cells.

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The Chemistry of SPE

New year – fresh start

If you’re like me, you start the new year off with a list of resolutions for the coming months – resolutions to be more fit or to secure a promotion at work or to reduce your carbon footprint. Whether you’re trying to improve your health or further your career, these are the types of goals that I like to refer to as getting “back to basics” because they require you to start with a solid foundation which you can build on to achieve success.

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