Salting‐out assisted liquid/liquid extraction with acetonitrile: a new high throughput sample preparation technique for good laboratory practice bioanalysis using liquid chromatography–mass spectrometry

Abstract

Acetonitrile, an organic solvent miscible with aqueous phase, has seen thousands of publications in the literature as an efficient deproteinization reagent. The use of acetonitrile for liquid-liquid extraction (LLE), however, has seen very limited application due to its miscibility with aqueous phase. The interest in LLE with acetonitrile has been pursued and reported in the literature by significantly lowering the temperature of the mixture or increasing the salt concentration in the mixture of acetonitrile and aqueous phase, resulting in the separation of the acetonitrile phase from aqueous phase, as observed in conventional LLE. However, very limited application of these methods has been reported. The throughput was limited. In this report, we report a new sample preparation technique, salting-out assisted liquid-liquid extraction with acetonitrile, for high-throughput good laboratory practice sample analysis using LCMS, Two compounds from an approved drug, Kaletra, were used to demonstrate the extractability of drugs from human plasma matrix. Magnesium sulfate was used as the salting-out reagent. Extracts were diluted and then injected into a reversed phase LC-MS/MS system directly. One 96-well plate was extracted with this new approach to evaluate multiple parameters of a good laboratory practice analytical method. Results indicate that the method is rapid, reliable and suitable for regulated bioanalysis. With minimal modification, this approach has been used for high-throughput good laboratory practice analysis of a number of compounds under development at Abbott.

Development and application of salting-out assisted liquid/liquid extraction for multi-mycotoxin biomarkers analysis in pig urine with high performance liquid chromatography/tandem mass spectrometry

“…It is also well known that these kind of polar organic solvents are miscible with water at any proportion. However, the addition of salts can reduce the mutual miscibility, and can even lead to phase separation [22]. Therefore, with the help of salt, the polar analytes which existed in the aqueous phase can selectively move into the polar organic phase.…”

Salting-out Assisted Liquid-Liquid Extraction for the Determination of Multiresidue Pesticides in Alcoholic Beverages by High Performance Liquid Chromatography

“…However, as can be seen from Figure 2, the highest peak areas of the analytes were observed when MgSO 4 was used as salting-out agent. This could be attributed to the highest ionic strength per unit concentration of MgSO 4 in aqueous solution as compared to the others [42]. Thus, MgSO 4 was selected for subsequent experiments.…”

“…The volume of acetontrile, the extraction solvent, as well plays a great role on the extraction performance of the SALLE procedure [31,37,42]. The effect of the acetonitrile volume on the extraction performance was investigated by varying its volume over the range of 0.5-2.0 mL.…”

“…At low volumes, phase separation between acetonitrile and aqueous phases was not clear and thus, collection of the organic phase was difficult. On the other hand, at higher volumes, the volume of organic phase obtained after phase separation is higher than its initial volume, indicating the existence of dissolved water in the organic phases [37,42]. Based on the experimental results, 1 mL acetonitrile was selected as the optimum volume in the subsequent experiments.…”

Evaluation and statistical analysis of the modified QuEChERS method for the extraction of pinoxaden from environmental and agricultural samples

“…However, LLE is considered expensive, tedious, laborious, time consuming, environmentally unfriendly, and potentially disposed to sample contamination when ultratrace determinations are necessary and not applicable to hydrophilic compounds (Anthemidis and Miró 2009;Pena-Pereira et al 2009;Zhang et al 2009). …”