含锂药剂在用于临床治疗精神疾病时需要对患者血清中锂元素浓度进行监测以在控制正常药效的同时防止锂中毒事故的发生。 目前临床医学检验血清中锂元素含量主要采用火焰原子吸收光谱和基于离子选择性电极的电化学技术。 但火焰原子吸收光谱技术需要使用乙炔钢瓶和空气压缩机, 存在仪器不能便携, 对实验室条件要求苛刻等缺点; 电化学方法存在电极处理与更换繁琐, 分析效率相对偏低等问题。 同时, 仪器可便携、 操作简单且对锂元素分析具有良好分析性能的液体阴极辉光放电-原子发射光谱技术尚未应用于医疗领域血清中锂含量的测定。 因此, 基于自制便携液体阴极辉光放电-原子发射光谱装置, 建立了血清中锂元素的高灵敏度分析方法。 系统考察了10~100倍血清样品稀释倍数对血清样品测试的干扰, 结果表明, 当血清样品稀释20倍以上时, 未发现显著的基体干扰, 可以较好地保证结果的可靠性。 对影响锂元素分析性能的分析谱线、 试液酸度等参数进行了系统优化, 结果表明671 nm为锂元素最佳测试谱线; 试液酸度对锂元素分析的灵敏度和稳定性影响显著, 采用1%硝酸( V/V)试液酸度可以保证良好的分析性能。 在优化的系统参数和实验条件下, 锂元素标准曲线的回归方程为: Ie=7 299 ρ_Li+400; R²=0.998 3。 当血清样品稀释20倍时, 该方法对锂元素的检出限为0.2 mg·L^-1。 对同一血清样品6次重复测试考察本方法的重复性, 相对标准偏差小于5%。 将本方法应用于血清标准样品(Trace Elements Serium L-2)中锂含量分析, 测定值与证书标称值一致。 表明该方法可以较好地应用于医疗检验领域实际血清样品中微量锂元素含量的测定。

The lithium in serum of the patients should be monitored to achieve the regular medical effect and prevent from lithium poisoning when the medicine containing lithium is adopted to treat the manic depression. At present, flame atomic absorption spectrometry and electrochemical methods are commonly used in lithium determination in clinic area. However, for the flame atomic absorption spectrometry method, the instrument can’t be portable as the C₂H₂ cylinder is necessary, for which the demands for the laboratory are critical. As for the electrochemical technique, the treatment of the electrodes is tedious and the analytical efficiency is somewhat low. The solution cathode glow discharge-atomic emission spectrometry, which has proved to be sensitive for Li determination with simple operation and portable instrument, has never been used in clinic Li test in serum. Therefore, a novel method was established for sensitive determination of lithium in serum based on a home-made portable solution cathode glow discharge- atomic emission spectrometer. The serum samples were pumped into the discharging chamber after dilution and acidification. Lithium in serum was excited by the plasma generated between the solution cathode and the solid metal anode, and the characteristic spectrum came into being in the common atmosphere and the signal collection and analysis were carried out by using a fiber optical spectrometer. The influence of dilution times within 10~100 on matrix interferences was comprehensively investigated and the results showed that no significant matrix interferences were observed when the dilution times were above 20 and the reliability could be basically ensured. The parameters influencing the analytical performances, including the analytical emission line, the acidity of the testing solution, etc, were optimized. The results showed that 671 nm was proved to be the ideal analytical emission line due to the strongest emission intensity and the non-significant spectral interferences while the best analytical performance could be achieved when 1% HNO₃( V/V)was adopted to keep the acidity of the solution on the premise of the suitable stability. Under the optimized conditions, the equation of the linear calibration curve was as follows: Ie=7 299 ρ_Li+400; R²=0.998 3. The limit of determination for lithium in the serum was 0.2 mg·L^-1 when the serum sample was diluted by 20 times. The relative standard deviation for the repeatability test based on 6 times tests of the serum was below 5%. This method was applied to the analysis of serum standard material. The detection result was in favorable agreement with the certified value, which showed that this method can be used in the determination of lithium in real serum samples of clinical tests.