Tuesday Trivia – Answer for October 2, 2018

Just a reminder of last week’s post:

EPA Method 8270 outlines a method for extracting a quantifying a number of compounds, of which hexachlorocyclopentadiene is one. However, this compound can be difficult to recover. Why? (choose all that apply)

(a) It is photoreactive and decomposes when exposed to light

(b) It is chemically reactive and reacts with certain organic solvents

(c) It has a relatively high vapor pressure and evaporates a bit at room temperature

(d)  It is susceptible to thermal degradation

(e)  None of the above

Answer: a, b and d

If you selected a, b, c and d, you were close. Hexachlorocyclopentadiene is a relatively reactive compound which lends it to photo-induced, chemical-induced and thermal-induced reactions; however, it is not hard to recover due to evaporative losses. In fact, this compound has a relatively low vapor pressure and is unlikely to rapidly evaporate from standards and samples that are at room temperature.

Join us next week to Expand Your Horizon!

Water Pollution – Are Killer Whales the Next Victims of PCB Contamination?

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.

Continue reading Water Pollution – Are Killer Whales the Next Victims of PCB Contamination?

Tuesday Trivia – October 2, 2018

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?

Continue reading Tuesday Trivia – October 2, 2018

5 Myths About Oil & Grease

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.

Continue reading 5 Myths About Oil & Grease

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:

Continue reading Tuesday Trivia – Answer for September 18

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.

Continue reading Alternative to Sodium Sulfate Drying

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.

Continue reading Monitoring Our Water Resources for a Sustainable Future

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.

Continue reading Extraction of 1,4 Dioxane from Drinking Water