Volatile. Flammable. Skin irritant. Respiratory irritant. Possibly fatal if swallowed. For those of you processing samples according to EPA Method 1664B, you’ve seen these hazard descriptions before – on the safety data sheet (SDS) for n-hexane. For those of you who aren’t familiar with (or have forgotten about) the hazards related to n-hexane, those are just a few. It also smells unpleasant and could explode if heated. It’s a relatively unpleasant organic solvent to work with and it begs the question:
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“Why do I keep seeing background contamination from phthalate and adipate when I do extractions for semi-volatiles?” This is one of the most common questions I’ve been asked when I’m traveling in the field. It’s an issue I’ve come across in my own lab on occasion and if you can’t find the source of your contamination, it can turn routine application work into a troubleshooting nightmare. Given how often I’ve seen these compounds cause contamination issues, I thought I’d review some of the most common sources for these.
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“Pesticides” is one of those terms that invokes a wide range of emotions in people. Some people smile when they think of the insecticides that keep their award-winning flower garden looking beautiful all season.
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In the first part of this 2-part blog series, I highlighted the improvements made by the EPA regarding the preparation and preservation of samples. In this post, I will focus more on the changes the EPA has made to Method 525 which affect the analysis of the prepared samples.
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Since its release in 1995, EPA method 525.2 has been one of the most widely used methods for quantifying semi-volatile compounds in drinking water. Chances are, if you work for or own a drinking water lab, you probably analyze for compounds in this method – at the very least, you’re probably at least familiar with the method.
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Phenolic compounds can be some of the most challenging compounds to extract from the compound lists in EPA Method 8270 and EPA Method 625.1. The recovery of these compounds suffer tremendously compared to some of the other target analytes on the list. So what exactly are phenols and why are they challenging to extract and quantitate?
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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.
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In the world of solid phase extraction (SPE), the list of media that is available seems to be ever-growing. From polymeric stationary phases, to silica-based media, and even molecularly imprinted polymers specifically designed for target analytes. The possibilities seem endless.
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In a never-ending list of chemical pollutants, a compound that is gaining a lot of attention is 1,4-dioxane. In fact, New Jersey just became the first state to set regulations on the quantity of 1,4-dioxane that can be present in drinking water.
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For thousands of years, tea has been one of the most popular drinks around the world. Not only is tea delicious, but it is also full of health benefits. Tea is an abundant source of antioxidants called polyphenols. One of these polyphenolic compounds, catechins, is found mostly in green tea.
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