Showing posts written by Stephanie J. Marin
Underloading your SLE+ samples can result in better partitioning and cleaner samples. Supported liquid extraction (SLE) is a simple clean-up technique similar to liquid-liquid extraction (LLE), but on...
Understanding the chemical properties of the compounds in your sample matrix, both the ones you want to detect and the ones you want to eliminate, is necessary for successful method development. Is th...
Supported Liquid Extraction (SLE) is a sample preparation technique that has been in use for over ten years now, but many analytical chemists don’t know about, or understand the best way to do an SLE ...
How the acid dissociation constant (pKa) affects sample preparation method development? Knowing and understanding the pKa of your compounds tells you if the compound can be ionized, and under what con...
Mixed mode Solid Phase Extraction (SPE) phases have become very popular for sample clean-up prior to analysis using mass spectrometry. Having the capability to retain compounds by two modes of interac...
What is a weak ion exchange SPE phase? What is their charge state and how they behave in function of pH conditions? When to choose them? This post will describe Biotage mixed mode weak ion exchange SP...
Most clinical and forensic labs have a used a traditional approach for drug testing called screen with reflex to confirmation. This involves analyzing samples using an immunoassay technique that ident...
Evaporative crosstalk is contamination that occurs during evaporation of the elution solvent after SLE or SPE extraction. Volatile analytes evaporate, then redistribute in adjacent wells in a 96-well ...
This is a question that I am often asked by very smart people that just haven’t had time to learn the process. An optimized sample preparation method is critical for an accurate, specific, robust clin...
Most clinical chemists have developed a blood, serum or plasma assay using a protein crash because it is inexpensive and generally removes proteins that interfere with detection or the analysis in som...