SLE, SPE and LLE – How are Those Different?

Liquid-liquid extraction (LLE), supported liquid extraction (SLE), and solid-phase extraction (SPE) have existed for decades and if you’re doing organic sample preparation, you’re probably quite familiar with at least one of these techniques.  But are you familiar with all of them?  How are they similar?  How are they different?  Let’s review!

Do Flow Rates Matter in SPE?

Have you ever wondered why solution flow rates are so important when performing sample preparation with solid phase extraction (SPE)?  If you have, read on – I have the answer for you! Throughout my college career, the phrase “like dissolves like” was referred to quite frequently.  This phrase was particularly relevant when we did solubility … Continue reading Do Flow Rates Matter in SPE?

Understanding SPE Retention Mechanisms

As a chemist, I’ve constantly stressed the importance of proper sample preparation.  Whether I’m diluting, digesting, preconcentrating, extracting, or performing a combination of these, sample preparation is the key to making my analysis a success, yet it’s often the most challenging part of my workflow.  Some of my preparation procedures are simply daunting – a … Continue reading Understanding SPE Retention Mechanisms

The Chemistry of SPE

New year – fresh start If you’re like me, you start the new year off with a list of resolutions for the coming months – resolutions to be more fit or to secure a promotion at work or to reduce your carbon footprint. Whether you’re trying to improve your health or further your career, these … Continue reading The Chemistry of SPE

Solid Phase Extraction (SPE) – What is That?

“Good data out requires good data in”. I have heard many versions of that phrase over the course of my career. The statement could apply to a wide range of topics; however, as a chemist, the basic premise highlights to me the importance of proper sample preparation before analysis.

EPA Methods and the Use of Drying Techniques

Do you ever tire of using sodium sulfate to dry your extracts?  I know I do.  That is why, whenever I get the chance to avoid using it, I do.  The worst experience when using sodium sulfate is when you do not use enough of it, and the sodium sulfate reaches its maximum capacity leading … Continue reading EPA Methods and the Use of Drying Techniques

Tackling Emulsions Just Got Easier

Believe it or not, we’re all familiar with emulsions.  Have you ever added food oil to a pot of water while cooking?  That’s an emulsion.  Do you put dressing on your salad?  It should be called salad emulsion – although, that may not have the same edible appeal.  Do you drink milk?  Emulsion.  What about … Continue reading Tackling Emulsions Just Got Easier

To Be or Not to Be Water Miscible

“Oh my!  This is crystal clear!” – said nobody who has ever read through an EPA Method. For anyone who processes samples in an EPA-regulated laboratory, you know that these methods can be very specific in some spots, and incredibly vague in others.  The complexity worsens if you’re following one method for sample cleanup and … Continue reading To Be or Not to Be Water Miscible

Spooky Stories or Laboratory Mishaps?

“There is a child in every one of us who is still a trick-or-treater looking for a brightly-lit front porch.” – Robert Brault It’s Halloween!  I assume you’ve carefully assembled your favorite movie character, comic book superhero or animal costume for a night of spooky fun.  If you’re me, this is the day you get … Continue reading Spooky Stories or Laboratory Mishaps?

10 Facts About Pesticides You Didn’t (Want to) Know

Pesticides have been widely used in the U.S. for decades to combat everything from weeds to insects to bacteria.  These compounds allow farmers to cultivate acres of successful crops and keep food on our dinner tables.  But every chemical poses a risk, so I always like to familiarize myself with the chemicals I’m being exposed … Continue reading 10 Facts About Pesticides You Didn’t (Want to) Know