IR technology is a rapid and convenient tool for both qualitative and quantitative analysis that has been around for over a century. Traditional IR spectroscopy relies on vibration energies from the molecular bindings, where IR emission is absorbed by the bond when it has the same frequency as the specific vibration or movement as the bond.
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:
Is there an alternative?
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!
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.
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.
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….