Application of Ultrasound-Assisted Emulsification Microextraction Based on Applying Low Density Organic Solvents to the Extraction and Determination of Mononitrotoluenes in Water Samples

Abstract

In this study, simple and efficient ultrasound-assisted emulsification microextraction (USAEME) based on applying low density organic solvents combined with gas chromatography-flame ionization detector (GC-FID) was developed for the preconcentration and determination of mononitrotoluenes (MNTs) in water samples. In this method, the fine droplets of toluene were formed and dispersed in the sample with the help of ultrasonic waves which accelerated the formation of the fine cloudy solution without using disperser solvents. Several factors influencing the extraction efficiency such as the nature and volume of organic solvent, extraction temperature, ionic strength and centrifugation time were investigated and optimized. Using optimum extraction conditions, dynamic linear ranges of 0.5-500 μg L -1 , and limit of detections (LOD) of 0.3 μg L -1 were obtained for o-nitrotoluene, m-nitrotoluene and p-nitrotoluene. Finally, the method was successfully applied to the extraction and determination of MNTs in the water samples in the range of micrograms per liter with relative standard deviations (RSD) < 12%. ]]>

Determination of Tea Aroma Precursor Glycosides: An Efficient Approach via Liquid Chromatography-Tandem Mass Spectrometry

“…Ultrasonic assisted extraction can achieve good recovery of analytes in solid substances due to its special cavitation, which has the advantages of simple operation, high efficiency, and reduction of trace analysis errors caused by volatilization or sample pollution. 34 According to the above solvent optimization, 90% methanol solution was used as the appropriate reagent for the simultaneous extraction of eight aroma precursor glycosides. Ultrasonic parameters that affect the extraction performance, such as temperature and time, were optimized in this study.…”