Are whales such as our beloved SeaWorld friend, Shamu, soon to be a distant memory? A recent study published by Science predicts a significant decline – possibly a complete population collapse – in killer whales, stemming from PCB pollution.
Happy Tuesday! This week’s question will focus on one of the EPA methods used for extracting semivolatile organic compounds (SVOCs) prior to analysis by GC/MS. Are you ready to Expand Your Horizon?
If you were ever a fan of the show MythBusters, you can appreciate the hours I spent watching myths being confirmed or busted in the most entertaining ways. For me, this show was appealing because the scientific theory was used to design and test experiments to produce facts about interesting phenomena such as: humans use only 10% of their brains, a household vacuum cleaner can generate enough suction to lift a car into the air, or a goldfish’s memory is only 3 seconds long.
It’s now 1 week past World Water Monitoring Day – tell us what you did to celebrate in the comments below:
For those who took last week’s quiz to measure their water quality knowledge, read on. The questions and answers are below:
If you are performing oil & grease analyses according to EPA Method 1664, you are familiar with the requirement to dry your extract prior to evaporation. There are those who might perform this step for reasons such as “this is the way we’ve always performed our extractions” or “the government-regulated method told me so” or “we have a giant container of sodium sulfate in the lab, so we might as well use it”; however, there is sound logic in removing water from your organic solvent prior to evaporating it.
As today is World Water Monitoring Day, I assume you are wearing your “I Water” t-shirt – or perhaps you are secretly wearing it to work, under your formal business attire? If so, you are probably in good company.
On the eve of World Water Monitoring Day, we thought we would post last Tuesday’s response a day earlier! Celebrations for tomorrow’s epic event might otherwise interfere.
Just a reminder of last week’s post:
According to EPA Method 1664 A/B, n-hexane is used as an extraction solvent and must have a minimum purity level of…
EPA Method 1664 B outlines the use of n-hexane as an extraction solvent and Section 1.7.2 specifies a minimum purity level of 85% (Method 1664 A has the same requirement).
Believe it or not, hexane solutions typically contain a mixture of 5 structural isomers (i.e. same molecular formula, different arrangement of atoms). N-hexane is the longest (least branched) of the 5 isomers, which gives it the highest boiling point and lowest vapor pressure. Therefore, specifying a minimum purity level of 85% means you’re dictating that at least 85% of the solution must contain the x-hexane isomer.
Join us next week to Expand Your Horizon!
PFAS chemicals can be found in every aspect of our life from nonstick pans and cleaning products to firefighting foam. This group of chemicals has caused concern nationwide as it has been found in drinking water and has shown to have negative effects on our health. Starting in the 1980s, chemicals in the PFAS family, PFOS and PFOA, were linked to a number of health concerns, from cancer to hormonal disruption. (See our earlier blog for terms and definitions). These chemicals are extremely difficult to get rid of because they do not break down in the environment and they build up in the body.
Happy Tuesday! This week’s question will focus on the EPA method for performing n-hexane extractions, otherwise known as “oil and grease” extractions. If you are ready to Expand Your Horizon, read on.
Today’s question: According to EPA Method 1664 A/B, n-hexane is used as an extraction solvent and must have a minimum purity level of…
(e) None of the above
Hazard a guess in the comments below! (need a hint? The answer isn’t “none of the above”)
Stay tuned next Tuesday….