可同化有机碳(AOC)检测方法的对比

Comparison of Determination Methods for Assimilable Organic Carbon(AOC)

水中可同化有机碳(AOC)浓度与异养菌总数(HPC)密切相关,高AOC含量会加速细菌的生长,由此引发水质劣变等问题。文中对比了平板涂布法、流式细胞术(flow cytometry,FCM)+纯菌接种与流式细胞术+土著菌接种检测AOC的方法,流式细胞术计数获得的P17、NOX和土著细菌标准曲线的判定系数R^2分别为0.729、0.957、0.921;平板涂布计数法的P17、NOX和土著细菌标准曲线的判定系数R^2分别为0.714、0.917、0.156。相较于平板涂布法,流式细胞术所测得的AOC标准曲线线性关系较好,所测结果稳定,且可对水中的全部细菌进行计数,克服了传统平板涂布法仅可检测水中活的且可培养的细菌的缺陷;在此基础上,使用土著细菌接种所表征的结果客观反映了水中细菌的存在状况。鉴于其计数快捷、可大批量检测、可区别计数、培养周期短,且误差小的特点,流式细胞术+土著菌接种检测AOC方法可为供水管理部门评判水质生物稳定性提供理论参考与技术支持。

The concentration of assimilable organic carbon(AOC)in water was closely related to heterotrophic plates counts(HPC).High AOC concentrations could accelerate the growth of bacteria and thus lead to poor water quality and other problems.Three methods of AOC concentration measurement-plate culture,flow cytometry(FCM)combined with inoculation of pure bacteria and flow cytometry(FCM)combined with inoculation of indigenous bacteria were compared in the study.Determination coefficients(R^2)of standard curves of P17,NOX and indigenous bacteria obtained by flow cytometry were 0.729,0.957 and 0.921,respectively,while in plate counting method were 0.714,0.917 and 0.156.Compared with plate culture,the result of AOC standard curve with FCM behaved more stable with a stronger linear relationship,and FCM could detect all of bacteria in water,thus overcame the defect of traditional plate culture method which could only detect both living and culturable bacteria.Results of applying indigenous bacteria as inoculated bacteria objectively reflected the characterization of bacteria in natural water.In view of its characteristics of rapid and distinguishable counting,short culture cycle and low error,the measurement method of AOC by FCM combined with indigenous bacteria inoculation could provide theoretical reference and technical support for water supply management departments to evaluate biological stability of water quality.