Comparison of Magnesium Sulfate and Sodium Sulfate for Removal of Water from Pesticide Extracts of Foods

Abstract

Water-miscible solvents, such as acetone and acetonitrile, effectively extract both polar and nonpolar pesticide residues from nonfatty foods. The addition of sodium chloride to the resulting acetonitrile–water or acetone–water extract (salting out) results in the separation of the water from the organic solvent. However, the organic solvent layer (pesticide extract) still contains some residual water, which can adversely affect separation procedures that follow, such as solid-phase extraction and/or gas chromatography. Drying agents, such as sodium sulfate or magnesium sulfate, are used to remove the water from the organic extracts. In the present study, we used nuclear magnetic resonance spectroscopy to study the composition of the phases resulting from salting out and to compare the effectiveness of sodium sulfate and magnesium sulfate as drying agents. The study showed that considerable amounts of water remained in the organic phase after phase separation. Sodium sulfate was a relatively ineffective drying agent, removing little or no residual water from the organic solvent. Magnesium sulfate proved to be a much more effective drying agent.

Enhancing the Thermotolerance of Entomopathogenic Isaria fumosorosea SFP-198 Conidial Powder by Controlling the Moisture Content Using Drying and Adjuvants

“…Once saturated with water, the gel can be regenerated by heating at 120℃ for 2 hr. Magnesium sulfate (anhydrous) is also used as a drying agent [ 28 ], the anhydrous form of which is hygroscopic (readily absorbs water from the air), making it difficult to weigh accurately. Therefore, magnesium sulfate hydrate is often preferred when preparing solutions, for example in medical preparations.…”

Development of QuEChERS Method for the Determination of Polycyclic Aromatic Hydrocarbons in Smoked Meat Products Using GC-MS from Qatar

“…Quenchers techniques replaced the complications of common, standard extraction techniques, and they provide a simple protocol for sample handling [ 36 ]. Acetonitrile was used as an extraction solvent in QuEChERS instead of acetone, which is thought to be an excellent separator from water, after the addition of salts [ 37 , 38 ]. Moreover, the cleanup protocols are adopted to effectively remove the matrix-matched materials such as polar pigment, fatty acids, organic compounds, and sugar [ 29 ].…”

Simultaneous determination of saflufenacil and three metabolites in five agriculture products using liquid chromatography—Tandem mass spectrometry

“…MeCN has shown to be the most advantageous solvent for extraction of pesticide residues from food, which gives high recoveries of a wide range of pesticides. Compared with other common extraction solvents, such as acetone and ethyl acetate, MeCN uses salts instead of nonpolar co‐solvent to induce a well‐defined phase separation with water, and MgSO 4 can better remove the residue water after the partitioning step (Anastassiades, Lehotay, Stajnbaher, & Schenck, ; Schenck, Callery, Gannett, Daft, & Lehotay, ). Therefore, MeCN was used as the extraction solvent in this study.…”