YSI(多参数水质检测仪)测定叶绿素a浓度的准确性及误差探讨

Discussion on accuracy and errors for phytoplankton chlorophyll-a concentration analysis using YSI(Multi-parameter water analyzer)

YSI(多参数水质检测仪)由于其快速、轻便的特点,已广泛应用于野外水体中叶绿素a的测定.通过将YSI测得的叶绿素a值与分光光度法测定值进行比较,对YSI6600水质测定的准确性和数据采集进行评估.结果显示,YSI测定值多数偏低,且与分光光度法测定值之间存在显著性差异;时间上,冬季比夏季具有更大的线性相关性.分段回归结果显示,随着叶绿素a浓度不断增大,两组数据的差值也不断增大.YSI测定误差产生于3个方面:(1)测定前YSI校准方法的不同;(2)其它种类具有荧光特性色素的存在;(3)YSI自身结构.

YSI（Multi-parameter water analyzer）is widely used to determine phytoplankton chlorophyll-a concentration in many fields because of its rapidness and portableness.The purpose of this study is to evaluate the efficacy of the YSI Environmental Monitoring System for water quality measurements and data collection by comparing two groups of data using laboratory method and YSI detections respectively.It shows that multiprobe readings are significantly different from laboratory analysis of chlorophyll.Mostly,multiprobe readings are much lower than laboratory analysis.All the data are mainly correlated in winter than summer.Linear regression of these two groups of data that were sectionalized into several intervals according to laboratory analysis of chlorophyll indicated that the disparity between these two groups of data becomes bigger with the increase of chlorophyll concentration.Errors are caused possibly by several factors：（1） calibration method of YSI,（2） existence of other kinds of pigment that fluoresces,and （3） the structure of YSI.