Solid Phase Extraction – Perceptions and Misconceptions

I was at a tradeshow the other day and overheard a conversation that stayed with me. The conversation was taking place between two colleagues who were reminiscing about their days in the college chemistry lab.

As a Ph.D. chemist myself, I’ve spent many years in the lab and I suddenly found myself looking back at my graduate school days and fondly reminisced with them. The part of their conversation that caught my attention was when I heard “Remember when we used to do all those extractions manually? How old school was that! People just dilute and shoot now, right?”

This statement stayed with me because the conferees were comparing solid phase extraction (SPE) and liquid-liquid extraction (LLE) methods against “dilute and shoot” methods for preparing LC-MS and GC-MS samples for analysis. Based on the tone and text of the conversation, “dilute and shoot” methods were viewed as the better, more modern approach to sample extraction.

The contempt for SPE and LLE was similar to the disdain one would have for a bulky, flip-to-open cell phone, and it suddenly occurred to me that the negative perception was coming from misconceptions related to sample preparation and sample extraction.

While the chemistry involved in liquid-phase and solid-phase extractions is well-characterized and hasn’t changed much in decades, the techniques for performing sample extractions have advanced with modern technology. Classical, wet bench chemistry (liquid-liquid extractions) has evolved to the use of automated systems and extraction disks or cartridges (solid-phase extractions).

In one of my previous blog posts, I explained some of the basic differences between solid-phase extraction and liquid-liquid extraction.  For a historical perspective on extraction, with emphasis on the advances made with solid phase extraction, check out this great presentation!

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