本文研究了在PH10.5的NH_3片-NH_4Cl缓冲溶液存在下,以Ca(或M_g)-酸性铬兰K-OP为体系,用偏最小二乘分光光度法同时测定合成样中的钙镁。在0～6.4×10~(-5)mol/l范围内Ca、Mg均符合Beer定律,结果表明满足微量分析要求。 In this paper, we studied the simultaneous determination of calcium and magnesium in synthetic samples by partial least-squares spectrophotometry in the presence of NH_3-NH_4Cl buffer solution of PH10.5 with Ca (or M_g) -chrome chromogenic K-OP as the system. In the range of 0 ~ 6.4 × 10 ~ (-5) mol / l, Ca and Mg all accorded with Beer’s law, and the results showed that the micro-analysis requirements were met.