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 to water breakthrough into your ‘what was supposed to be a dried extract.’  Then, you must dry the extract again with more sodium sulfate.  When you are a high throughput lab, redoing steps is not ideal.  Unfortunately, EPA Methods 525.2 and 525.3 require sodium sulfate drying as the drying technique, to name a couple, but not all EPA methods require sodium sulfate for drying.  That is why when there is an alternative technique available and you are permitted to use it, why not use it?!

Continue reading EPA Methods and the Use of Drying Techniques

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