A method for simultaneous determination of acetaldehyde,acrolein,acrylonitrile and pyridine in water by purge-and-trap-gas chromatography-mass spectrometry ( GC-MS) was reported.These compounds were concentrated by purging and trapping fol-lowed by desorption before GC-MS measurement using the HP-VOC capillary column for separation and selective ion mode ( SIM) for MS detection.External calibration was used for quantification.The following experimental conditions were used:the sampling vol-ume was 25 mL,purging gas flow was 40 mL/min,purging temperature was 40 ℃,purging time was 15 min,desorption time was 2 min,desorption temperature was 200℃,and baking time was 20 min.Under this condition,it was determined that the concentrations of acetaldehyde and pyridine were between 0.025 and 0.60 mg/L,and acrolein and acrylonitrile were between 0.002 5 and 0.10 mg/L.The calibration curve showed good linearity with the correlation coefficient r>0.995.The method detection limits of acetalde-hyde,acrolein,acrylonitrile and pyridine were 0.001 6,0.001 3,0.000 5 and 0.002 1 mg/L,respectively.The recovery rates ranged between 87.8%and 114.3%in three different spiked levels.The relative standard deviation (n=6) was from 2.51%to 10.4%. Three batches of water samples were analyzed.The recovery rates ranged between 79.2%and 103.8%for the waste water,and rela-tive standard deviation (n=6) was from 3.04%to 6.39%.
建立了基于索氏提取-固相萃取净化,气相色谱-质谱联用仪测定固定污染源飞灰中多环芳烃类有机污染物的方法,检验了滤筒和溶剂中杂质对测定的影响并提出了解决方案;优化了索氏提取的溶剂体系和提取条件,提高了提取效率;优化了净化程序;建立了基于内标法和选择离子检测的气相色谱-质谱联用仪测定方法,验证了方法的准确性.该方法解决了溶剂和滤筒带入的杂质以及样品基体对测定结果的干扰,组分提取完全,结果准确,是测试固定污染源飞灰中多环芳烃类有机污染物的有效方法.
采用X-射线荧光光谱法(XRF)对丁二烯橡胶样品进行B-U元素的扫描检测,考察了丁二烯橡胶样品的制样方法、样片厚度、X-射线扫描范围和扫描时间等实验条件,对检测到的元素使用聚合物模式进行半定量计算元素含量.将XRF测得的元素含量换算成氧化物含量进行加和计为灰分,对15个样品测得的灰分在0.0122％(质量分数)～0.1240％(质量分数)之间,与标准方法(炭化氧化法)测得的灰分进行比较,灰分小于0.1％的样品,其相对误差绝对值小于70.2％,灰分大于0.1％的样品,其相对误差绝对值小于30.1％.
以安捷伦1290超高效液相色谱仪-6470三重四级杆质谱联用仪为例,介绍了液相色谱仪主要组件自动进样器、二元泵、柱温箱、检测器组,质谱主要部件离子源、毛细管、离子光学组件等的维护和保养相关操作及注意事项,并通过仪器维护前后的自动调谐结果进行对比,发现维护后杂质离子峰减少,主离子峰的响应变高,显著提高了分析检测的灵敏度.
目的:依据化学分子式建立一种离子色谱法测定硫酸铵纯度的方法.方法:取硫酸铵试剂溶于超纯水,分别测定铵根离子和硫酸根离子的含量,通过阴、阳离子的结果分析,换算出硫酸铵的纯度含量.结论:硫酸铵溶液测定中,铵根离子的含量小于硫酸根离子含量的2倍,因此以铵根离子的含量计算出硫酸铵的纯度为99.4％.
