分光光度法检测百草枯中毒患者血清中百草枯浓度。
Serum paraquat concentration detected by spectrophotometry in patients with paraquat poisoning.
机构信息
Department of Nephrology, Tenth People's Hospital of Tongji University, Shanghai 200072, China (Li CB, Li XH, Wang Z, Peng A); Tongji Medical School, Tongji University, Shanghai 200092, China (Jiang CH).
出版信息
World J Emerg Med. 2011;2(3):179-84. doi: 10.5847/wjem.j.1920-8642.2011.03.004.
BACKGROUND
Paraquat (PQ) is a world-wide used herbicide and also a type of common poison for suicide and accidental poisoning. Numerous studies have proved that the concentration of serum PQ plays an important role in prognosis. Spectrophotometry, including common spectrophotometry and second-derivative spectrophotometry, is commonly used for PQ detection in primary hospitals. So far, lack of systematic research on the reliability of the method and the correlation between clinical features of patients with PQ poisoning and the test results has restricted the clinical use of spectrophotometry. This study aimed to evaluate the reliability and value of spectrophotometry in detecting the concentration of serum PQ.
METHODS
The wavelengths for detecting the concentration of serum PQ by common and second-derivative spectrophotometry were determined. Second-derivative spectrophotometry was applied to detect the concentration of serum PQ. The linear range and precision for detection of PQ concentration by this method were confirmed. The concentration of serum PQ shown by second-derivative spectrophotometry and HPLC were compared in 8 patients with PQ poisoning. Altogether 21 patients with acute poisoning 4 hours after PQ ingestion treated in the period of October 2008 to September 2010 were retrospectively reviewed. The patients were divided into higher and lower than 1.8 μg/mL groups based on their concentrations of serum PQ measured by second-derivative spectrophotometry on admission. The severity of clinical manifestations between the two groups were analyzed with Student's t test or Fisher's exact test.
RESULTS
The absorption peak of 257 nm could not be found when common spectrophotometry was used to detect the PQ concentration in serum. The calibration curve in the 0.4-8.0 μg/mL range for PQ concentration shown by second-derivative spectrophotometry obeyed Beer's law with r=0.996. The average recovery rates of PQ were within a range of 95.0% to 99.5%, relative standard deviation (RSD) was within 1.35% to 5.41% (n=6), and the lower detection limit was 0.05 μg/mL. The PQ concentrations in serum of 8 patients with PQ poisoning shown by second-derivative spectrophotometry were consistent with the quantitative determinations by HPLC (r=0.995, P<0.0001). The survival rate was 22.2% in patients whose PQ concentration in serum was more than 1.8 μg/mL, and the incidences of acidosis, oliguria and pneumomediastinum in these patients were 55.6%, 55.6% and 77.8%, respectively. These clinical manifestations were different significantly from those of the patients whose PQ concentration in serum was less than 1.8 μg/mL (P<0.05).
CONCLUSIONS
For common spectrophotometry, the wavelength at 257 nm was not suitable for detecting serum PQ as no absorbance was shown. Second-derivative spectrophotometry was reliable for detecting serum paraquat concentration. Serum PQ concentration detected by second-derivative spectrophotometry could be used to predict the severity of clinical manifestations of patients with PQ poisoning, and PQ content higher than 1.8 μg/mL 4 hours after ingestion could be an important predictive factor for poor prognosis.
背景
百草枯（PQ）是一种世界范围内广泛使用的除草剂，也是自杀和意外中毒的常见毒物。大量研究证实，血清 PQ 浓度在预后中起着重要作用。分光光度法，包括普通分光光度法和二阶导数分光光度法，常用于基层医院检测 PQ。迄今为止，缺乏对该方法可靠性和百草枯中毒患者临床特征与检测结果之间相关性的系统研究，限制了分光光度法的临床应用。本研究旨在评估分光光度法检测血清 PQ 浓度的可靠性和价值。
方法
确定普通和二阶导数分光光度法检测血清 PQ 浓度的波长。应用二阶导数分光光度法检测血清 PQ 浓度。确定该方法检测 PQ 浓度的线性范围和精密度。比较 8 例 PQ 中毒患者的血清 PQ 浓度的二阶导数分光光度法和高效液相色谱（HPLC）检测结果。回顾性分析 2008 年 10 月至 2010 年 9 月期间收治的 21 例 PQ 摄入后 4 小时急性中毒患者。根据入院时二阶导数分光光度法检测的血清 PQ 浓度，将患者分为高于和低于 1.8μg/ml 两组。采用学生 t 检验或 Fisher 确切概率法分析两组间临床表现严重程度的差异。
结果
普通分光光度法检测血清 PQ 浓度时，无法找到 257nm 的吸收峰。二阶导数分光光度法检测的 0.4-8.0μg/ml 范围内 PQ 浓度的校准曲线符合比尔定律，r=0.996。PQ 的平均回收率在 95.0%至 99.5%之间，相对标准偏差（RSD）在 1.35%至 5.41%（n=6）之间，检测下限为 0.05μg/ml。8 例 PQ 中毒患者的血清 PQ 浓度的二阶导数分光光度法检测结果与 HPLC 定量测定结果一致（r=0.995，P<0.0001）。血清 PQ 浓度高于 1.8μg/ml 的患者的生存率为 22.2%，这些患者酸中毒、少尿和纵隔气肿的发生率分别为 55.6%、55.6%和 77.8%，这些临床表现与血清 PQ 浓度低于 1.8μg/ml 的患者明显不同（P<0.05）。
结论
对于普通分光光度法，257nm 波长不适合检测血清 PQ，因为没有吸光度。二阶导数分光光度法可用于检测血清百草枯浓度。二阶导数分光光度法检测的血清 PQ 浓度可用于预测 PQ 中毒患者的临床症状严重程度，摄入后 4 小时血清 PQ 含量高于 1.8μg/ml 可能是预后不良的重要预测因素。
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