An automated in-syringe switchable hydrophilicity solvent-based microextraction.

Area of Science:

• Analytical Chemistry
• Environmental Chemistry
• Pharmaceutical Analysis

Background:

• Developing efficient and automated methods for analyzing pharmaceuticals in biological samples is crucial.
• Traditional sample preparation techniques can be time-consuming and labor-intensive.
• Switchable hydrophilicity solvents (SHS) offer tunable solvent properties for advanced extraction techniques.

Purpose of the Study:

• To introduce a fully automated in-syringe switchable hydrophilicity solvent-based microextraction (SHS-MBE) approach.
• To investigate Di-(2-ethylhexyl)phosphoric acid as a novel SHS for microextraction.
• To apply the developed method for the determination of antimicrobial drugs in human urine.

Main Methods:

• An automated in-syringe microextraction procedure using Di-(2-ethylhexyl)phosphoric acid as SHS.
• The method involves dissociation in alkaline solution, in situ organic phase generation via acidification, and phase separation.
• High-Performance Liquid Chromatography with Ultraviolet detection (HPLC-UV) was used for quantification.

Main Results:

• The SHS-MBE method was successfully applied to determine sulfamethoxazole and sulfamethazine in human urine.
• Linear calibration curves were obtained in the ranges of 0.06-50 mg L⁻¹ for sulfamethoxazole and 0.13-50 mg L⁻¹ for sulfamethazine.
• Low limits of detection (0.02 mg L⁻¹ for sulfamethoxazole, 0.04 mg L⁻¹ for sulfamethazine) and a sample throughput of 12 samples h⁻¹ were achieved.

Conclusions:

• The proposed fully automated in-syringe SHS-MBE is an effective technique for analyzing antimicrobial drugs in complex matrices.
• The method demonstrates potential for assessing drug acetylation in metabolic studies.
• This approach offers a promising alternative to conventional sample preparation methods in pharmaceutical analysis.