Zhu Yanbei, Kitamaki Yuko, Numata Masahiko
National Metrology Institute of Japan (NMIJ), National Institute of Advanced Industrial Science and Technology (AIST).
Anal Sci. 2017;33(2):209-215. doi: 10.2116/analsci.33.209.
Inductively coupled plasma tandem quadrupole mass spectrometry (ICP-QMS/QMS) measurements after xylene dilution were investigated as a method for determining the elements (Na, Mg, K, Ca, P, and S) in a biodiesel fuel (BDF) candidate reference material (RM). Optimizations were respectively carried out for the following parameters to obtain the best performance for measurements: O flow rate (additional gas to the carrier gas) to ensure complete combustion of the xylene solvent in the plasma, plasma power to obtain lower background signal intensities for Na and K, O flow rate (reaction cell gas) to remove any spectral interference with the S, H flow rate so as to remove spectral interference with Ca. After optimization, the lower detection limits of Na, Mg, K, Ca, P, and S were 0.0004, 0.00004, 0.0003, 0.00012, 0.00005, and 0.002 mg kg, respectively. Typical relative standard deviations were 2.1, 2.0, 1.7, 1.1, 2.5, and 2.5% for Na, Mg, K, Ca, P, and S, respectively, where the elemental concentrations in the BDF sample were, respectively, ca. 1 mg kg each for Na, Mg, K and Ca, ca. 2 mg kg for P, and ca. 6 mg kg for S. The established method was applied to the homogeneity assessment of a candidate RM of BDF made from palm oil. The relative uncertainties of the homogeneity were 0.3, 0.4, 0.6, 0.3, 1.6, and 0.6% for Na, Mg, K, Ca, P, and S, respectively.
研究了二甲苯稀释后的电感耦合等离子体串联四极杆质谱法（ICP-QMS/QMS），作为测定生物柴油燃料（BDF）候选参考物质（RM）中元素（Na、Mg、K、Ca、P和S）的一种方法。分别对以下参数进行了优化，以获得最佳测量性能：氧气流速（载气的辅助气体），以确保二甲苯溶剂在等离子体中完全燃烧；等离子体功率，以获得较低的Na和K背景信号强度；氧气流速（反应池气体），以消除对S的任何光谱干扰；氢气流量，以消除对Ca的光谱干扰。优化后，Na、Mg、K、Ca、P和S的最低检测限分别为0.0004、0.00004、0.0003、0.00012、0.00005和0.002 mg/kg。对于Na、Mg、K、Ca、P和S，典型的相对标准偏差分别为2.1%、2.0%、1.7%、1.1%、2.5%和2.5%，其中BDF样品中各元素的浓度分别约为：Na、Mg、K和Ca各约1 mg/kg，P约2 mg/kg，S约6 mg/kg。所建立的方法应用于由棕榈油制成的BDF候选RM的均匀性评估。对于Na、Mg、K、Ca、P和S，均匀性的相对不确定度分别为0.3%、0.4%、0.6%、0.3%、1.6%和0.6%。
