Laser Thermal Lens Spectrometry And Its Application

AbstractThe method for the determination of phosphorus, nitrate nitrogen, coppeT, cobalt,nickel and cationic surfactan by laser thermal lens spectrometry(LTLS) has been stUdiedin this thesis. The LTLS has been aPplied to the analysis of the samples with satisfactoryresult. The thesis is divided into five parts:The first part: Review. A review of the LTLS analytica1 principle and aPplicationtO inorganic elements is given.The second part: Determination of cationic sdrictam by LTLS. The new reagent,l-hydroxy-2-(5-nitro-2-pyridylaZ acid (5-NO,-PAH)can form 1: 2 ion association complex with cationic suIfactan CPB and CTMABrespectively in a weak basic medium toH9.44). The determitmation conditions and themechanism were discussed. A novel method with high sensitivity for the determination ofcationic suIfactam is developed. The method has been aPplied to the analysis of thewastewater and moat water samples.The third part: Color development system based on the reactions of tYansitionmetal ion copper, cobalt, and nickel with 5NO,-PAH is investigated. With the study onthe suitable condition for this color development reaction and the effect of the interferingions, a novel method of determining the coppery, cobaltic and niccolous in a mixtUresimultaneously by LTLS is developed. The comparison between LTLS andsPectrophotometry is presented. Cu'+, Co'+, Ni2+ in synhetic samples and hair samples aredetermined simultaneously by LTLS without separation.The 4th part: A simple and effective method fOr the determination of trace amounsof phosphate by laser thermal lens spectrometry, which is based on the developing ofmolybdenum blue and malachite green in acidic medium, is presented in this paper. Theeffect factors were investigated. By making a compallson, the difference betWeen themethods is discussed in detail. It is shown that the method of molybdenum blue has awider linear range, and the method of malachite green has higher sensitivity. Themethod has been aPplied to the determination of trace amounts of phosphate in riveY, taPwater and soil saxnples successfullyThe 5th part: Determination of nitrate nitrogen in the soil by laser thermal lensspectrometry. The method for the determination of nitrate nitIogen in soil is presenied.The method is based on the sensitive color development reaction betWeen nitIate nitrogenand diphenylamine in sulphuric acid medium. The influence of determination conditionsis discussed. The linear range is 0~l5ng/ml for nitrate nitrogen. The relative standarddeviation is smaller than 5%, and the recovery is 97.2~104.3%. The method of LTLS hasbeen aPp1ied to the determine nitrate nitrogen in soil samples.