Determination of 9 kinds of volatile halogenated alkane and chlorobenzene compounds in water by gas chromatography-mass spectrometry with purge and trap method

In this study, in the face of water environmental pollution, a more simple and efficient detection method was obtained for simultaneous determination of 9 kinds of volatile halogenated alkane and chlorobenzene compounds in water by PT/GCMS. By optimizing the purge and trap conditions, the optimal experimental conditions were obtained as follows: purge time was 15 min, purge temperature was 35 °C, purge velocity was 40 mL/min, desorption time was 2 min, desorption temperature was 240 °C. The linearity of the method was good, and the correlation coefficients were all greater than 0.999. The minimum detection limit(MDL) of the method was 0.1 μg/L. The average recovery rate ranged from 85.4 %~102.1 % in surface water and drinking water with relative standard deviation (RSD) ranged from 5.3 %-9.2 % in the spiked concentration levels of 5 μg/L and 10 μg/L. This method has the advantages of simple operation, good separation effect, rapid detection, high recovery and good precision, and can simultaneously meet the requirements of 9 kinds of volatile organic compounds detection in drinking water and surface water. This work provides a new method for the detection of volatile organic compounds in water and will have great significance for the detection of water quality.

Automatic On-Line Purge-and-Trap Sequential Injection Analysis for Trace Ammonium Determination in Untreated Estuarine and Seawater Samples

An innovative automatic purge-and-trap (P&T) system coupled with fluorimetric sequential injection (SI), for the on-line separation and preconcentration of volatile compounds, is presented. The truth of concept is demonstrated for the ammonium fluorimetric determination in environmental water samples with complex matrices without any pretreatment. The P&T flow system comprises a thermostated purge-vessel where ammonium is converted into gaseous ammonia and a trap-vessel for ammonia collection. This configuration results in matrix removal as well as analyte preconcentration, avoiding membrane-associated problems. All the main parameters affecting the efficiency of a P&T system were studied and optimized. The proposed method is characterized by a working range of 2.7–150.0 μg L−1 of NH4+, with a detection and quantification limit of 0.80 and 2.66 μg L−1, respectively, for a 10-mL sample consumption. The accuracy of the method was assessed by recovery assays in seawater, estuarine, and lake water samples as well as by the analysis of standard reference material.