镧盐增敏-微波等离子炬原子发射光谱法测定原油中钙  

Determination of calcium in crude oil by lanthanum salt sensitization-microwave plasma torch atomic emission spectrometry

作　　者：张起凯[1] 孙蕊 赵杉林[1] ZHANG Qikai;SUN Rui;ZHAO Shanlin(School of Petrochemical Engineering,Liaoning Petrochemical University,Fushun 113001,China)

机构地区：[1]辽宁石油化工大学石油化工学院,辽宁抚顺113001

出　　处：《冶金分析》2021年第5期75-80,共6页Metallurgical Analysis

基　　金：国家自然科学基金(21171083)。

摘　　要：以微波等离子炬(MPT)为光源,氩气为载气和工作气体建立起来的微波等离子炬原子发射光谱法(MPT-AES)可以在低激发功率和低工作气体流量下正常工作,具有分析速度快、设备运行成本低和多元素同时测定等优点。但是低功率MPT工作气体温度较低,存在激发能力弱和抗基体干扰能力差等不足。实验针对MPT-AES测定钙中的基体干扰问题,依据镧盐作为释放剂在火焰原子吸收光谱分析中的应用,研究了镧盐存在下使用MPT-AES测定钙的方法。实验结果表明,镧盐对MPT-AES测定钙具有明显的增敏效果,当测试体系中镧质量浓度为0.600mg/mL时,可使钙的发射强度提高78.6%,检出限由2.2×10^(-3)μg/mL下降为1.5×10^(-3)μg/mL,且使共存元素允许量得到显著提高。方法用于原油中钙的测定,结果的相对标准偏差(RSD,n=6)小于4.0%,测定值与火焰原子吸收光谱法相一致。Microwave plasma torch atomic emission spectrometry(MPT-AES)is established using a microwave plasma torch(MPT)as the light source,and using argon as the carrier gas and working gas.It can work normally at low excitation power and low operating gas flow,and has many advantages,including fast analysis speed,low operation cost of equipment and simultaneous determination of multiple elements.However,the temperature of working gas in low-power MPT is low,which suffers from weak excitation ability and poor resistance to matrix interference.Aiming at the problem of matrix interference during the determination of calcium by MPT-AES,on the basis that lanthanum salts are employed as the releasing agent in flame atomic absorption spectrometry analysis,the method for the determination of calcium by MPT-AES in the presence of lanthanum salts was investigated.Experimental results showed that the lanthanum salt had significant sensitizing effect on the determination of calcium by MPT-AES.When the mass concentration of lanthanum in testing system was 0.600 mg/mL,the emission intensity of calcium could be increased by 78.6%.The limit of detection decreased from 2.2×10^(-3)μg/mL to 1.5×10^(-3)μg/mL,and the allowed amount of coexisting elements was significantly increased.The proposed method was applied for the determination of calcium in crude oil.The relative standard deviation(RSD,n=6)of determination results was less than 4.0%.The measurement results were consistent with those obtained by the flame atomic absorption spectrometry.

关 键 词：微波等离子炬原子发射光谱法(MPT-AES) 钙 镧盐 增敏 原油 

分 类 号：O657.31[理学—分析化学]