| A new method was developed for the group analysis of toxaphene mixtures using a comprehensive two-dimensional gas chromatography coupled with micro electron-capture detector(GC×GC-μECD).Different polarity and selectivity columns,including DB-XLB,DB-1MS and BP-1,were used as first dimension and combined with columns of increasing polarity in the second dimension,i.e.BPX-50.An DB-1MS(20 m×0.25 mm×0.25 μm) combination with BPX-50(2 m×0.1 mm×0.1 μm) yielded highly structured chromatograms and revealed a complex mixture of 923 compounds.GC×GC-μECD parameters,including temperature programs,carrier gas flow rate and modulation period were also optimized.Toxaphene congeners were well separated with the optimized methods.The peak areas of all congeners of different chlorinated toxaphene were calculated.It is found that hepta ,octa and nona chlorinated compounds were the major components and contribute 85% of the total toxaphene mass.The matrix-matched external standard calibration curves were used for quantitative analysis.Linear range of this method were 10-500 μg/L and limit of detection were 0.2-0.6 μg/L of the different chlorinated toxaphene.The repeatability and reproducibility at a concentration of 10 μg/L evaluated with RSDs(n=7) of 9%-20%.It can be seen the use of comprehensive two-dimensional GC substantially improves the quality of toxaphene analysis compared to one-dimensional gas chromatography (1D-GC),hundreds congeners could be separated in toxaphene after a run which took less than 2 h.The results illustrate the potential of the GC×GC-μECD developed for the fast analysis of trace amount of complex compounds. |