对扩散分光光度法测定蒜粉成分分析标准物质(GBW 10022)中氟化物进行不确定度评定.测定结果不确定度的来源包括标准溶液定值、标准溶液配制、试样溶液配制、试样溶液重复性测定、氟化物标准曲线拟合和测量仪器6个分量,其中贡献最大的是氟化物标准曲线拟合引入的不确定度,其次是试样溶液配制引入的不确定度和标准溶液定值引起的不确定度.结果表明,国家标准物质GBW10022中氟化物的定值结果为(33.67±0.582)μg/g(k=2).

The content of organic matter in soil was determined by the potassium dichromate - sulfuric acid digestion system with hot plate heating-air cooled tube repeating reflow. The influence factors of determining organic matter content, including digestion temperature, boiling time and interference factor, were studied. The optimal digestion condition for measurement of soil organic matter was obtained as follows: the digestion temperature 220 ℃ and the boiling time 8 min. The results showed that the repeating reflux of air cooled tube kept the constant acidity of the digestion system and reduced the evaporation, which was beneficial to the dissolution of soil organic matter. The national standard material validation showed that the measured value was in agreement with the standard value, and the test results had good reproducibility. The relative standard deviation was less than 0.88%.This method can further reduce the testing cost, and is more environmentally friendly, reliable, and has strong adaptability to the environment and high testing efficiency.

化学分析中误差在所难免,尤其受技术人员、所用仪器、实验过程等的影响容易引入一些误差,影响化学分析结果的准确性.本文分析化学分析中误差发生原因,提出控制误差的相关策略,以供参考.

提出了加速溶剂萃取-气相色谱-质谱法测定土壤中6种硝基苯类化合物的方法.样品通过ASE萃取后脱水浓缩,经Florisil固相萃取小柱净化测定.在气相色谱分离中用TG-5MS石英毛细管色谱柱为固定相,在质谱分析中采用选择离子监测(SIM)模式,采用内标法定量.该方法的校准曲线的线性良好,样品中各组分曲线相关系数R2均大于0.9950,6种硝基苯类化合物的检出限为0.18～0.80μg·kg-1,平均回收率在52.7％～122.4％,相对标准偏差(n=7)在3.14％～6.52％之间,适合测定土壤中的6种硝基苯类化合物.

氯化物型卤水采集与保存是液体矿物卤水研究的难题.察尔汗盐湖矿区卤水的化学组成特征是:平均矿化度为421.9g·L-1,Cl-的质量浓度190.1g·L-1,Na+的质量浓度69.84g·L-1.为此文中借鉴了地下水样品采集与保存原理,通过对氯化物型卤水样品的采集与保存试验,获得了氯化物型卤水采集与保存控制技术条件,对高盐度卤水、海水采集与保存也具有重要的推广应用价值.

本法基于火试金法的原理,试验将试样不经配料后高温熔融富集,直接在900℃灰吹后,得到金银合粒,再将金银合粒经王水溶解后,原子吸收分光光度计测定,方法简捷快速,可操作性强,结果稳定,降低了对周围环境的污染.

The samples were treated troμgh preconcentration by fire assay and decomposition by dilute nitric acid,aqua regia,and the content of gold was determined by flame atomic absorption spectrometry,it was overcome that the unstable results of samples that were fired under 650℃,dissolved by aqua regia and absorbed by activated carbon were determined by flame atomic absorption spectrometry,and reworked rate higher of precision difference was also overcome,the analysis time was shortened.The method is validated by the state material standard,and the results matched with the standard values.