Zhu Yanbei, Nakano Kazumi, Shikamori Yasuyuki
National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST).
Agilent Technologies Japan, Ltd.
Anal Sci. 2017;33(11):1279-1284. doi: 10.2116/analsci.33.1279.
The analysis of fluorine was carried out by measuring BaF ions with an inductively coupled plasma tandem quadrupole mass spectrometer (ICP-QMS/QMS). After optimization, a radio frequency power of 1300 W was found to benefit for the production of BaF ions while suppressing the production of BaOH ions. After optimization of the reaction cell gas, it was found that the best performance for measuring BaF could be achieved at a flow rate of O in the range from 0.65 to 0.75 mL min. The signal intensity of BaF depended linearly on the concentration of Ba when it was not higher than 100 mg kg. The co-existence of metallic cations, such as Na in the sample, might suppress the generation of BaF ions in the plasma, while anions might not cause such a kind of interferences. The background equivalent concentration (BEC) and the lower detection limit (LDL) of fluorine were 0.4 and 0.06 mg kg, respectively, by adjusting the samples to a 10 mg kg Ba matrix. The concentration of fluorine in a certified reference material (ERM-CA015a) was determined with the present method, for which the observed value was (1.36 ± 0.05)mg kg, which agreed with the certified value (1.3 ± 0.1)mg kg, where both values were shown as (mean value ± expanded uncertainty) with a coverage factor of (k = 2) for calculating the expanded uncertainty giving a level of confidence of approximately 95%. The present method was applied to the analysis of a tap water sample collected in the laboratory, for which the results of recovery tests gave a recovery around 100% with good reproducibility.
采用电感耦合等离子体串联四极杆质谱仪（ICP-QMS/QMS）测定BaF离子来进行氟的分析。优化后发现，1300W的射频功率有利于BaF离子的产生，同时抑制BaOH离子的产生。优化反应池气体后发现，当O的流速在0.65至0.75mL/min范围内时，测量BaF可获得最佳性能。当BaF的信号强度不高于100mg/kg时，其与Ba的浓度呈线性关系。样品中金属阳离子（如Na）的共存可能会抑制等离子体中BaF离子的产生，而阴离子可能不会引起此类干扰。通过将样品调整为10mg/kg的Ba基质，氟的背景等效浓度（BEC）和最低检测限（LDL）分别为0.4和0.06mg/kg。用本方法测定了有证标准物质（ERM-CA015a）中的氟浓度，其观测值为(1.36±0.05)mg/kg，与认定值(1.3±0.1)mg/kg相符，其中两个值均表示为（平均值±扩展不确定度），计算扩展不确定度时的包含因子为(k = 2)，置信水平约为95%。本方法应用于实验室采集的自来水样品分析，回收率测试结果显示回收率约为100%，重现性良好。
