Study On Sequential Injection Coupled With Chemiluminescence For The Determination Of Dimethoate And Resorcinol In Environmental Water Samples

For the past years, The topic of environmental water pollution has been increasingly concerned. The components of water pollution include metal ions, cyanide, phenol, pesticides, etc. The pesticides can enter into the body of humans by food, producing hazards of teratogenic, mutagenic and carcinogenic. The phenol as protoplasm poison is belong to high toxic substances. When human intake of a certain amount of them, they would occur the symptoms of acute poisoning. When human drink the water polluted by phenol for a long time, they may have headache, rash, anemia, or a various nervous system symptoms. Moreover, phenol is a kind of important industrial pollutants, when the concentration of phenol in water is low, can lead to the peculiar smell of fishes; When the concentration of phenol in water is high, can lead to the dead of fishes. Therefore, establishing convenient, quick, sensitive, and reliable methods for the detection of the two components at low levels will be meaningful to the control of environmental pollution, the monitor of water quality and the health of human beings.Chemiluminescence (CL) method is an attractive and powerful detection technique owing to its analytical advantages such as low detection limit, very high sensitivity, wide linear dynamic range, fast response and simple equipment. When chemiluminescence detection was coupled with SIA analysis, its features were reserved, and the shortcomings, such as inconvenience of reaction process control and poor repeatability caused by fast reaction, were overcome. Combination CL with SIA remarkably improved the repeatability, accuracy and analytical frequency of the determination results. In this dissertation, the sequential injection coupled with chemiluminescence detection technique was proposed and applied to the determination of cyanide and nitrite and satisfactory results were obtained.The first chapter of the dissertation introduced the concept, classification, origin, harm of pesticides and the review on the progress of pretreatment methods, the progress of analytical methods and the progress of degradation methods for the determination of pesticides in recent years. The pretreatment methods include matrix solid-phase dispersion(MSPD), supercritical fluid extraction(SFE), microwave-assisted extraction(MAE), solid phase extraction (SPE), gel permeation chromatography(GPC) and accelerated solvent extraction(ASE); The analytical methods include gas chromatographic method(GC), gas chromatography-tandem mass spectrometry(GC-MS), thin layer chromatography(TLC), high performance liquid chromatography(HPLC), High performance liquid chromatography tandem mass spectrometry(HPLC-MS), capillary electrophoresis(CEP), immunoassay, biosensor method, fluorescence analysis and Chemiluminescence; The degradation methods include physical method, chemical method and biological method.The second chapter of the dissertation described a sequential injection online gas diffusion coupled with chemiluminescence in determination of dimethoate in water samples. In the developed FIA-CL system, the alkaline hydrolysis of dimethoate with NaOH was performed on-line in presence of hexadecylpyridinium chloride (HPC) (as an enhancer). The oxidation of the product of hydrolysis with Ce(IV) in hydrochloric medium induced chemiluminescence. The cation interference was eliminated by passing the sample solution through cation resin micro-column. The chemiluminescent intensity is proportional to the concentration of dimethoate in the range of 1-100μg/L and 100-800μg/L respectively. The method provided a limit of detection of only 0.17μg/L(3σ/K). The relative standard deviation for eleven repeated measurements for 20μg/L dimethoate was 1.3%. The sampling frequency is 153 samples per hour. The method was applied to the determination of dimethoate in environmental waters with the recoveries in 85.9%-119.4%.The third chapter of the dissertation described a sequential injection online gas diffusion coupled with chemiluminescence in determination of resorcinol in water samples. In the developed FIA-CL system, resorcinol was oxidized by potassium permanganate inducing chemiluminescence. And in presence of formaldehyde, the chemiluminescence intensity was significantly enhanced. The chemiluminescent intensity is proportional to the concentration of dimethoate in the range of 1.0×10-8-4.0×10-5 mol/L, with a correlation coefficient of 0.9991. The relative standard deviation for eleven repeated measurements for 1×10-5 mol/L resorcinol was 1.7%. The sampling frequency is 180 samples per hour. The method provided a limit of detection of only 3.4×10-9 mol/L (3σ/K). The method was applied to the determination of resorcinol in environmental waters with the recoveries in 85.0%-118.5%. The method was applied to the determination of resorcinol for four water samples.In the last chapter, a summary for the characteristic of sequential injection coupled with chemiluminescence detection technique was described.