| With the continuous deterioration of the environment, water and organic matter is gradually increasing, the current method can not satisfy a variety of trace volatile organic compounds in water testing requirements. Therefore, the urgent need to establish a convenient, fast and high sensitivity method, a variety of volatile organic compounds in the water were measured.Purge and trap- gas chromatography- mass spectrometry is currently the most widely used method for determination of volatile organic compounds in water, the water is so far able to discern from the most advanced scientific methods more organic matter. In this study, a variety of instruments with water before treatment on the 55 kinds of volatile organic compounds were detected, comparative analysis, obtained good results.1. In this study, research and discussion by the separation of different instruments under otherwise identical conditions, change instruments, gas chromatography- mass spectrometry degree of separation is much higher than gas chromatography. In gas chromatography separation of 58.2%, while in the gas chromatography- mass spectrometry resolution reached 98.18 percent, to accurately separate the number of peaks to 54 kinds. For gas chromatography(GC) and gas chromatography- mass spectrometry(GC-MS) separation of statistical analysis, the results proved Gas Chromatography- Mass Spectrometry separation superior to gas chromatography.2. In contrast to the degree of separation between the different columns, we will present the most effective measurement of volatile organic compounds in water three columns for comparison, the standard solution of the same concentration of the three columns were purged into the catch Set-GC-MS were compared, HP-VOC(60m × 0.20 mm, 1.12μm) isolation rate 98.18%, DB-5MS was 50.91% DB-624 was 74.55%, compared to found in HP-VOC(60m × 0.20 mm separation, 1.12μm) capillary column Determination of 55 kinds of volatile organic compounds is good, the number of peak detection separated peaks of 54 kinds of(m-xylene and p-xylene can not be separated). It proved with separation of HP-VOC good.3. Adoption of the liquid-liquid extraction method-GC-MS, headspace-GC-MS and purge and trap-GC-MS three methods to calculate the standard curve fit line R value comparison liquid-liquid extraction method-GC-MS, R value in the range between 0.9825- 0.9996, headspace-GC-MS, R value in the range between 0.9954- 0.9997 Purge and Trap-GC-MS method, R value in the range of 0.9966 to 0.9999, blowing Sweep trap-GC-MS method R value is higher than the other two methods, a good linear range.4. The method of recovery were measured in this study method for determining the recovery in the range of 81.2% ~ 112.5% and relative standard deviation(RSD) in the range of 1.07%- 8.26%. At the same spiking concentration, on the same sample, respectively, with a liquid-liquid extraction-GC-MS and purge and trap-GC-MS determination of two methods were measured six times, relative to traditional liquid-liquid extraction-GC- MS methods Purge and Trap-GC-MS method for the determination of volatile organic compounds in water recoveries relatively high accuracy.5. Through the optimization of water pre-treatment methods, solid sodium chloride added to the water and found a marked increase in response, studies have shown that sodium chloride was added to the precipitation of volatile organic compounds in water to a certain extent, improve the sensitivity of the method, the detection limit of the range within 0.010μg /L~0.141μg / L range, high sensitivity.6. The precision of the study in line with national standards, precision RSD range between 1.64- 4.69%, high precision, can be applied to the actual sample analysis.By comparing several methods commonly used method for detecting volatile organic compounds in water and the establishment of the subject and found that this research Purge and Trap-GC-MS method recovery, accuracy, precision, high sensitivity, linearity The correlation coefficient and good. |
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