Tandem use of solid‐phase extraction and dispersive liquid–liquid microextraction for the determination of mononitrotoluenes in aquatic environment

Abstract

Solid-phase extraction (SPE) in tandem with dispersive liquid-liquid microextraction (DLLME) has been developed for the determination of mononitrotoluenes (MNTs) in several aquatic samples using gas chromatography-flame ionization (GC-FID) detection system. In the hyphenated SPE-DLLME, initially MNTs were extracted from a large volume of aqueous samples (100 mL) into a 500-mg octadecyl silane (C(18)) sorbent. After the elution of analytes from the sorbent with acetonitrile, the obtained solution was put under the DLLME procedure, so that the extra preconcentration factors could be achieved. The parameters influencing the extraction efficiency such as breakthrough volume, type and volume of the elution solvent (disperser solvent) and extracting solvent, as well as the salt addition, were studied and optimized. The calibration curves were linear in the range of 0.5-500 μg/L and the limit of detection for all analytes was found to be 0.2 μg/L. The relative standard deviations (for 0.75 μg/L of MNTs) without internal standard varied from 2.0 to 6.4% (n=5). The relative recoveries of the well, river and sea water samples, spiked at the concentration level of 0.75 μg/L of the analytes, were in the range of 85-118%.

A simple solvent collection technique for a dispersive liquid–liquid microextraction of parabens from aqueous samples using low‐density organic solvent

“…Since its introduction, it has fast become one of the most popular analytical sample preparation technique because of its advantages such as simplicity, rapidity, and low consumption of solvents and reagents. To date, DLLME has been applied for the analysis of various organic and inorganic pollutants in aqueous samples and even in solid samples after an adequate pretreatment .…”

“…However, these solvents are extremely toxic and environment unfriendly. Alternative extractants such as ionic liquids or fatty alcohols have been considered to be more environmentally friendly than chlorinated solvents, and using these solvents in DLLME has also provided good results. Fatty alcohols are low‐density solvents such as 1‐octanol, 1‐decanol, 1‐undecanol, 1‐dodecanol, and 2‐dodecanol, floating above the aqueous phase after the DLLME.…”

Separation and Preconcentration by Dispersive Liquid–Liquid Microextraction Procedure: Recent Applications

“…UV at fixed wavelength was used for determination of a grand variety of organic compound such as chlorophenols [65], drugs [66,71,77,82,84], insecticides [69,70], aromatic amines [72,73], pesticides [74,75], UV filters [81], additive flame retardant [64,67,68,85], antioxidants [86], etc.…”

“…Sobhi et al [86] applied IL-DLLME procedure to the extraction and determination of some antioxidants (Irganox 1010, Irganox 1076 and Irgafos 168) in water samples. The method seems to be precise, reproducible, time independent and linear over a wide concentration range and the non-volatile IL reduces the exposure danger in comparison with the conventional organic solvent.…”

Developing an alcoholic‐assisted dispersive liquid–liquid microextraction for extraction of pentachlorophenol in water

“…The advantages of this novel method include very short extraction time, ease of operation, low cost, and high enrichment factors (EFs). Since its introduction, DLLME has been successfully applied for the determination of trace metal and organic pollutants such as PCP in water samples. One of the main disadvantages associated with DLLME, however, is that it uses toxic extraction solvent.…”