Application Of Ultrasound-assisted Chemiluminescence Technology In Environmental Analysis

In recent years, chemiluminescence has been widely used in the fields ofenvironment, biology, food and medicine because of its low detection limit, widelinear range and simple instrumentation.The generation and feature of ultrasonic, aswell as the principle, development and application of chemiluminescence analysiswere summarized firstly. Secondly the prospect for ultrasonic combined withchemiluminescence was introduced in detail. And then systematic researches of theconstruction and application of the novel ultrasonic-chemiluminescence were carriedout.The main contents included: the determination of trace cadmium in environmentalsamples by luminol-EDTA chemiluminescence system, the establishment of the novelultrasonic water-chemiluminescence system, the optimization of conditions and theinstrument parameters, and the determination of kinds of real samples by theproposed method,The details are listed as follows:Firstly, the analysis of trace heavy elements by chemiluminescence method wasstudied. It was found that a weak chemiluminescence signal appeared inluminol-EDTA systems. The addition of cadmium could strongly increase thechemiluminescence signal which increased proportionally with the increasement ofconcentration of cadmium. According to this, a new ultrasensitive chemiluminescencemethod of determination of cadmium was built. After optimizing the reactionmedium, concentration of reactants and the instrument parameters, the linear range forcadmium was1-30ng L-1，the detection limit was0.23ng L-1，RSD was3.5%。Secondly, the idea of oxidation of luminol chemiluminescence by free radicalswhich was produced by water treated ultrasound was proposed, a new off-linechemiluinescence system was established based on the reaction of H2O treated withultrasound with luminol. The result showed that obvious chemiluinescence signal wasproduced by the reaction of H2O treated with ultrasound mixed with alkaline luminol,and the addition of ascorbic acid could obviously increase chemiluinescence signal.after the parameters of ultrasound and instruments were optimized, Ascorbic acidconcentration is proportional to the luminous intensity in the range of0.1to10mmolL-1, the detection limit for cadmium was15nmol L-1，the relative standard deviationwas1.3%. Compared with the traditional system, the new method not only had highsensitivity, but also greener and environmentally friendly becase there was no need toadd any preservative oxidant.Finally, On the basis of offline ultrasound, we designed the disc and spiralultrasonic reactor and built a new online ultrasound-assisted chemiluinescence system.Researches showed that by treated with ultrasound three minutes, deionized watercould produce a strong chemiluinescence signal with alkaline luminol solution. The sensitivity of this method was influnced by the shape of the reactor, the distancebetween the reactor and transducer and the height of water bath. The onlineparameters of the experiment were optimized, and the reaction mechanism wasdiscussed. the ascorbic acid and L-cysteine in the vegetables and envireonmentalsamples were detected by the new online system, the detection limits were39nmolL-1and37nmol L-1respectively, RSD were3.5%and2.6%.The new method wasrapid, simple, sensitive and green which can be used to determine the above substancein real samples.