Plasma Sample Preparation for Solid Phase Extraction of Chosen Xenobiotics, Utilizing Salts Differing in Ion Chaotropicity

Abstract

Buffer solutions or simply water remains the dominant diluents of plasma sample for solid phase extraction (SPE) of xenobiotics. The present study examined the effect of varying chaotropicity and concentration of plasma sample additives on protein solubilization and effectiveness of drug recovery by the use of SPE. Three drugs: diclofenac, propranolol, and warfarin, differing in acid-base properties and exhibiting strong affinity to plasma albumin have been chosen. Depending on the type and concentration of additive used for the plasma dilution, diversified values of recoveries were obtained. Due to the plasma dilution by chaotropic salts, analytes eluted off the SPE sorbent suffered from very little matrix interference in contrast to samples diluted by ionic liquids solutions. The results of drug recovery show that the addition of only a few milimolar concentration of NaCl or NaPF₆ can improve recovery of acidic drugs: propranolol and diclofenac from plasma sample. In case of warfarin, additive containing two chaotropic ions EMIMBF₄ appeared to be more effective. Results match spectrophotometric analysis conducted on samples of human serum albumin dissolved in the presence of examined additives. For NaPF₆, NaCl, and EMIMBF₄ at the lower concentrations, minimum of the absorbance values were also observed.

Keywords:

• chaotropic salts
• ionic liquids
• plasma
• sample preparation
• solid phase extraction
• xenobiotics

Notes

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