采用直接进水样,用气相色谱氢焰离子化检测器(FID)测定水中吡啶,并用正交法对柱温、载气流量、尾吹流量、 分流比四个气相色谱重要条件参数进行优化,确定了直接进样气相色谱法测定水中吡啶的最佳操作条件,该方法检出限为0.06 mg/L,实验结果表明该方法简便、准确,在此条件下直接进样检测水中吡啶,可获得良好的分析结果.

挥发性脂肪酸(VFA)是厌氧消化过程的重要中间产物,在反应器运行中,出水VFA用作重要的控制指标.通过色谱条件探索将各种脂肪酸分离,同时研究了水样酸碱度,吸附等对测定的影响,进一步优化了废水中挥发性脂肪酸的测定.方法的检出限在0.99～1.77 mg/L,回收率在90.9％～102.7％之间,相对标准差(n=5)在1.3％ ～3.8％之间.

An ion chromatography(IC) method was developed for the determination of acid red 26 in dyeing wastewater.100 mmol/L sodium perchlorate solution–acetonitrile(1∶1) was used as the eluent at flow rate of 1.0 mL/min.The analytical column was DIONEX IonPac AS16(250 mm×4 mm).The detection was performed by a Dionex VWD3100 UV/Vis detector.The quantitive analysis of external standard calibration curves was used.The linear range of the method for acid red 26 was 0.1–20 mg/L(r=0.999?9).The average recoveries were 98.4%–101.0% with the relative standard deviations(RSD) no more than 0.5%.The detection limit(S/N=3) was 0.03 mg/L.The RSDs of the retention time,peak area and peak height were 0.10%,0.50% and 0.15%,respectively.The interference of many anions in dyeing wastewater was elimated by using the UV detecter.

Amounts of nitrobenzenes in water sample were determined by GC with microelectron capture detector.Nitrobenzene compounds in water sample were extracted with a mixture of ethylacetate,benzene and diethyl ether(2+1+0.02),and separated on HP-1701 capillary column(30 m×0.25 mm,0.25 μm).The 9 nitrobenzenes were separated within 11.5 min.Linear relationships between values of peak area and mass concentration of the 9 nitrobenzenes were obtained in the same range of 0.001-5.0 mg·L-1.Test for recovery was made by standard addition method,giving recovery in the range of 92.0%-108% with RSD′s(n=5) less than 5.0%.

It was found that the precision of the results of determination of volatile organic compounds(VOC′s) in water samples by GC using the HP 7694E head space automatic sampler was poor and unsatisfactory,and that the cause was the designing defect of its heating device.Measure for improvement was proposed by preheating the water samples to a temperature close to the temperature of the detection chamber(25±2) ℃ in water bath,and setting the conditions of head-space sampling at 55 ℃ and 15 min.Four VOC′s(i.e.CHCl3,BrCHCl2,Br2CHCl and CHBr3) were determined under the prescribed conditions.Values of RSD′s(n=5) found were in the range of 2.2% to 3.3%.