分光光度法检测血清百草枯质量浓度及意义

The clinical significance of determining serum paraquat by spectrometry

目的评价分光光度法测定血清百草枯（paraquat，PQ）质量浓度的可靠性及其临床意义。方法验证普通分光光度法和二阶导数分光光度法测定血清PQ质量浓度的检测波长后，采用二阶导数分光光度法测定血清PQ质量浓度，确定其线性范围并评价其准确性；采用该法测定8例PQ中毒患者血清PQ质量浓度并与高效液相色谱法测定值比较分析其可靠性；对上海市第十人民医院肾病免疫科2008年10月至2010年9月收治的口服PQ4h以上入院的21例急性PQ中毒患者的资料行回顾性统计分析，根据该法测定患者入院时血清PQ质量浓度是否大于1．8μg／mL分为两组，采用成组t检验和Fisher精确概率法对两组患者的临床特征进行统计分析。结果（1）普通分光光度法检测含PQ血清样本时在257nm波长处未见明显吸收峰；（2）二阶导数分光光度法测定血清PQ质量浓度在0．4—8．0μg／mL范围内呈现良好的线性关系，相关系数为0．996；回收率为95．0％～99．5％，相对标准差（RSD）为1．35％～5．41％（n=6），检出下限为0．05μg／mL；（3）8例PQ中毒患者血清PQ质量浓度二阶导数分光光度法测定值与HPLC法检测值相吻合，r=0．995，P〈0．01；（4）血清PQ质量浓度〉1．8μg／mL组患者存活率为22．2％，酸中毒和少尿发生率55．6％，纵膈气肿发生率77．8％，与血清PQ质量浓度〈1．8μg／mL组比较差异均有统计学意义（P〈0．05）。结论（1）普通分光光度法用于测定血清PQ质量浓度不能采用257nm为检测波长；（2）二阶导数分光光度法用于检测血清百草枯质量浓度可靠性高；（3）二阶导数分光光度法测定值可用于中毒患者的临床严重程度判断，口服PQ中毒4h后血清质量浓度〉1．8μg／mL是患者预后不良的重要指标。

Objective To evaluate the reliability and clinical value for detecting paraquat （PQ） concentration in serum by spectrometry. Methods The determinations of wave length for detecting serum PQ concentration by ordinary spectrometry and second -derivative spectrometry were carried out. When the second -derivative spectrometry was used for detecting PQ in serum, the linear range and precision for PQ concentration were well defined. The results of serum PQ concentration determined by second - derivative spectrometry and by HPLC （high performance liquid chromatography） were compared in 8 patient with PQ poisoning. A total of 21 patients with acute poisoning after PQ ingestion over 4 hours admitted from October 2008 through September 2010 were retrospectively studied. Patients were divided into two groups as per the serum concentrations more than 1.8μg/mL or less than that by second - derivative spectrometry on the day of admission. The severity of clinical manifestations between two groups was analyzed with t - test or Fisher＇s exact probabilities analysis. Results （ 1 ） The absorption peak of 257 nm could not be found by using ordinary spectrometry to detect the PQ concentration in serum. （2） The calibration curve in the 0.4 - 8.0 μg/mL range for detecting PQ concentration by second - derivative spectrometry observed the Beer ＇s law （r=0. 996） . The average retrieval rate of PQ was within the range of 95.0% - 99. 5% with relative standard deviation （RSD） within 1.35% - 5.41% （n = 6）, and the lowest detection limit was 0. 05μg/mL. （3） The resuhs of PQ concentrations from 8 patients with PQ poisoning detected by second - derivative spectrometry were consistent with those of the quantitative determinations by HPLC （ r = 0. 995, P 〈0. 01 ） . （4） The survival rate of patients with serum PQ concentration more than 1.8vg/mL was 22. 2% , and the incidences of acidosis, oligouria and pneumomediastium in these patients were 55.6% , 55.6% and 77. 8% , respectively. These clinical manifestations were significantly different from those in patients with serum PQ concentration less than 1.8 μg/mL （ P 〈 0.05 ） . Conclusions （ 1 ） It was inappropriate to take 257 nm as the determination wave length for detecting serum PQ concentration by ordinary spectrometry. （2） The method of second - derivative spectrometry was reliable for detecting serum PQ concentration. （3） Serum PQ concentration detected by second derivative spectrometry could be used to predict the severity of clinical manifestations of patients with PQ poisoning and was an important predictive factor for poor prognosis if the serum PQ concentration more than 1.8 μg/mL after PQ ingestion over 4 hours.