The energy in microwave plasma torch atomic emission spectrometry (MPT-AES) is supplied by microwave ,which is similar to the characteristic of inductively coupled plasma atomic emission spectrome-try (ICP-AES) .It has some advantages such as high atomization efficiency ,rapid analysis speed and sim-ple operation .However ,the application researches of this technology is only limited in the optimization of instrumental working conditions at present ,and lack of effective solving measures for the interference of some coexisting elements .Argon was selected as carrier gas and working gas .The working conditions for the determination of calcium in crude oil by MPT-AES were investigated .Meanwhile ,the influence of co-existing elements on the determination of calcium was discussed .The results showed that the mass concen-tration of calcium in range of 0 .010-6 .00 μg/mL was linear to the corresponding emission intensity with correlation coefficient of r=0 .999 8 under the following experimental conditions :the analytical line was Ca 393 .366 nm ,the microwave power was 85 W ,the carrier gas flow rate was 1 350 mL/min ,and the work-ing gas flow rate was 650 mL/min .The detection limit of calcium was 5 .6 × 10-3 μg/mL .The interference test results indicated that the determination of calcium was not influenced by 7 times (mass concentration) of sodium ,3 times of iron and cobalt ,1 time of magnesium ,copper and aluminum .However ,1 time of vanadium and nickel had interference .The tolerant amount of aluminum ,cobalt ,nickel ,magnesium , iron ,copper and vanadium could be increased by 5 times using 0 .5 mL of 5 g/L EDTA and 0 .5 mL of 10 g/L phenanthroline solution . The experimental method was applied to the determination of calcium in crude oil ,and the found results were basically consistent with those obtained by flame atomic absorption spectrometry (FAAS) .The relative standard deviations (RSD ,n=6) were between 1 .6% and 2 .2% .%微波等离子体炬原子发射光谱法（MPT-AES）是利用微波源提供能量，其与电感耦合等离子体原子发射光谱法（ICP-AES）特点类似，具有原子化效率高、分析速度快和操作简单等优点，但是目前对该技术的应用研究仅限于仪器工作条件的优化，对某些共存元素的干扰缺乏有效的解决措施。实验以氩气为载气和工作气，详细考察了MPT-AES测定原油中钙的工作条件和共存元素对钙测定的影响。结果表明，选择Ca 393.366 nm为分析谱线，微波功率为85 W ，载气流量为1350 mL／min ，工作气流量为650 mL／min ，钙质量浓度在0.010～6.00μg／m L范围内与其对应的发射强度呈线性，线性相关系数 r＝0.9998；方法中钙的检出限为5.6×10－3μg／mL。干扰试验结果表明，7倍于钙质量浓度的钠，3倍于钙质量浓度的铁、钴，1倍于钙质量浓度的镁、铜、铝不影响钙的测定；1倍于钙质量浓度的钒、镍干扰钙的测定。在0.5 mL 5 g／L EDTA和0.5 mL 10 g／L 邻菲罗啉溶液的联合作用下，可使铝、钴、镍、镁、铁、铜、钒的允许量至少提高到5倍。将实验方法应用于原油中钙的测定，测定结果与火焰原子吸收光谱法（FAAS）基本一致，相对标准偏差（RSD ，n＝6）为1.6％～2.2％。
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