Rapid screening of chemical warfare agents (nerve agents) using dimethyl methylphosphonate as simulant substances in beverages by hollow fiber membrane-protected solid phase microextraction followed by corona discharge ion mobility spectrometry.

The following work presents a new, rapid, potential to be portable, convenient, and low-cost method using hollow fiber membrane-protected solid phase microextraction followed by corona discharge ion mobility spectrometry which was used for determining dimethyl methylphosphonate in beverages. Response surface methodology based on the design of Box-Behnken was implemented for optimizing the different factors influencing the proposed method for obtaining the best results. Optimal extractions were calculated with 65 µm polydimethylsiloxane-divinylbenzene fiber, fiber equilibration time of 10 min, stirring rate of the sample solution at 750 rpm, and extraction temperature of 50 °C. The proposed technique provided linear range (0.5-50 µg mL-1), good linearity (>0.991), and repeatability (the relative standard deviations of 5.42% and 8.37% of intra- and inter-day analyses, respectively) under the optimized extraction conditions. Finally, the developed method was successfully used for determining dimethyl methylphosphonate in beverages such as coffee mix, fruit juice, tap water, milk, and tea.

Surfactant-assisted electromembrane extraction combined with cyclodextrin-modified capillary electrophoresis for the separation and quantification of Tranylcypromine enantiomers in biological samples.

Surfactant-assisted electromembrane extraction coupled with cyclodextrin-modified capillary electrophoresis was developed for the separation and determination of Tranylcypromine enantiomers in biological samples. This combination would provide a new strategy for selective and sensitive determination of target analytes. The addition of surfactant in the donor solution improved the analyte transport into the lumen of hollow fiber that resulted in an enhancement in the analytes migration into acceptor solution. Optimization of the variables, affecting proposed method, was carried out and best results were achieved with a 175 V potential as driving force of the electromembrane extraction, 2-nitrophenyloctylether as the supported liquid membrane, donor solution containing 0.2 mM Triton X-100 with pH 3 and 0.1 M HCl for acceptor solution. Then, the extract was analyzed using cyclodextrin-modified capillary electrophoresis method for separation of Tranylcypromine enantiomers. The best results were obtained with a phosphate running buffer (100 mM, pH 2.0) containing 7% w/v hydroxypropyl-α-cyclodextrin. Under the optimum conditions, a low limit of detection (3.03 ng/mL), good linearity (R2  > 0.9953), and relative standard deviations below 4.0% (n = 5) were obtained. Finally, this procedure was applied to determine the concentration of Tranylcypromine enantiomers in urine samples with satisfactory results.