Tuesday Trivia – Answer for September 18

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:

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Alternative to Sodium Sulfate Drying

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.

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Monitoring Our Water Resources for a Sustainable Future

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.

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Tuesday Trivia Answer for September 11, 2018

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…

Answer: 85%

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!

Tuesday Trivia – September 11, 2018

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…

(a) 80%
(b) 85%
(c) 95%
(d) 98%
(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….

Extraction of 1,4 Dioxane from Drinking Water

1,4 dioxane – sometimes referred to as just dioxane – has gotten a lot of press since the U.S. EPA added it to the third Unregulated Contaminant Monitoring Rule (UCMR 3). It is a relatively common solvent in analytical laboratories; however, it also finds use as a stabilizer for manufacturing items such as shampoo, cosmetics and food additives. After the EPA deemed this compound “likely to be carcinogenic to humans” and found it in a number of groundwater sources across the U.S., 1,4 dioxane was added to the UCMR 3 list and is now a regulated, routinely monitored contaminant.

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SVOCs – Should I be Worried About Those?

If you’ve ever taken on a home renovation project and needed to purchase wall paint, you may have looked at “low VOC” or “no VOC” paint. Even if you don’t know what VOCs are, you are likely familiar with the terrible, headache-inducing smell that greets you when you pry the lid off a new can. Not only is the odor unpleasant, but the fumes are harmful when you breathe them in over a prolonged period of time.

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The Basics of Solvent Drying

Solvent drying is a key step in many laboratories that are using organic solvents for syntheses and extractions. In the case of hexane extractions during oil and grease measurements, this step is necessary to ensure that the extracts are accurately dried, concentrated and weighed.

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PFCs in the Antarctic

“Magical.”

If I had to use a single word to describe aquariums, it would be “magical.” Whether you’re a child or a child at heart (like me!), it is easy to get lost with the turtles, sea lions, eels, sharks and any other aquatic life you can imagine. The exhibits closely mimic the sights, sounds and smells of each aquatic environment – so closely, that you might think you’re out in the ocean or in the middle of the Antarctic.

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