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Tandem use of solid‐phase extraction and dispersive liquid–liquid microextraction for the determination of mononitrotoluenes in aquatic environment
Author(s) -
Sobhi Hamid Reza,
Farahani Hadi,
Kashtiaray Amir,
Farahani Mohammad Reza
Publication year - 2011
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.201000529
Subject(s) - chromatography , chemistry , sorbent , detection limit , elution , extraction (chemistry) , solid phase extraction , solvent , enrichment factor , analyte , calibration curve , aqueous solution , sample preparation , acetonitrile , salting out , analytical chemistry (journal) , adsorption , organic chemistry
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%.