Development Of Determination Device For Chromium(?) In Water Based On Flow Micro Reaction System

With the development of human activities,more and more heavy metals with state of bio-available entered the water,soil,atmosphere and other environmental media.Along with the accumulation of Cr???in the human body,Cr???will lead to various types of chronic diseases such as cancer and nervous system disorders.Therefore,various detection of Cr???were developed.However,as a traditional method,chemical colorimetric method consumed a large amount of reagents,produced a large sum of contaminant and took long time to analyze;Atomic Absorption Spectrometry?AAS?,Ion Chromatography?IC?,Inductively Coupled Plasma-Mass Spectrometry?ICP-MS?and other methods need high cost and high requirement equipment;sensor method was rapid and efficient,but the analysis accuracy was relatively low.In order to overcome the defects of above methods,it is necessary and urgent to develop an accurate,rapid and low consumption determination of heavy metals in the water.In this paper,a novel determination method for chromium???in water based on microfluidic chip or PEEK tube was established.And by analytic hierarchy process?AHP?and establishing a hierarchical model,the test parameters of two devices were optimized.Meanwhile,test performances of two devices were also discussed in this paper.Compared to national standard method,the two decices had significant advantages,.This paper mainly includes the following several aspects:?1?The devices,who have the advantages,such as simple device structure and small size for easy carrying,were designed in this paper.The use of a microfluidic pump and microfluidic chip simplified the method of measurement.Meanwhile,the use of an optical fiber spectrometer increased the sensitivity and accuracy and facilitated the detection of Cr???in water on site.?2?The test parameters of two devices were optimized in this paper.The influence of temperature and current velocity on the determination of hexavalent chromium in water samples was analyzed from the three aspects of measuring time,reagent consumption and reaction degree.And the optimum conditions for the determination of hexavalent chromium in water sample were obtained by establishing hierarchical structure model.The results showed that the optimum conditions for determination of hexavalent chromium in water sample based on microfluidic chip were 40?L/min of micropump pump speed,20?of temperature and 7mins of measuring time,and the optimum conditions for determination of hexavalent chromium in water sample based on PEEK tube were 40?L/min of micropump pump speed,40?of temperature and 10mins of measuring time.?3?Test performance of two devices were discussed in this paper.Two devices had significant advantages in the test parameters.Specifically,for the device based on mivrofluidic chip,the indication errors were less than 0.40%,the repeatability were 1.92%,0.20%at Cr⁶⁺concentration of 0.10 mg/L and 1mg/L,the linearity was-0.11%at Cr⁶⁺concentration of 0.60 mg/L,the method detection limit?MDL?was2.69 ppb,zero drift was 0.09%,and range drift was 1.26%.For the device based on PEEK tube,the indication errors were less than 4%,the repeatability was 1.48%,0.22%at Cr⁶⁺concentration of 0.10 mg/L and 1mg/L,the linearity was 0.79%at Cr⁶⁺concentration of 0.60 mg/L,the method detection limit?MDL?was 1.89 ppb,zero drift was 0.09%,range drift was 0.54%.The repeatability,MDL,analysis time and reagent consumption of two devices in this paper are better than the national standard method.Especially,the analysis time and reagent consumption were far less than the national standard method.The determination of hexavalent chromium in water sample based on microfluidic chip and PEEK tube only need 7mins,10mins and0.58mL,0.66mL reagent to detect Cr⁶⁺in water,while the national standard method need 28m L and 25mins to detecet.The accuracy of the two devices is in the scope of5%,which meets the requirements of relevant national standard.In summary,determination device for Cr???based on flow micro reaction system in water has advantages of high accuracy,high repeatability,low detection limit,short analysis time,and less reagent consumption.And,it can be potentially used for development of on-line monitoring equipment and portable detectors.