Flow Injection / Cloud Point Extraction - Optical Instruments Associated With Analysis Of Biological Samples Of Trace Chromium, Arsenic, Lead, Cadmium Forms,

With the development of science and technology, the determination of trace elements often requires more sensitivity. FIA (flow injection spectrophotometry) and AAS (atomic absorption spectrophotometry) have a very High sensitivity and in the process of determination they require a few volume, but if determine the sample directly it will face a lot of difficulties or even impossible. Because on the one hand, the analysis of a very low content of elements lack of high sensitivity or the state of the samples do not suitable for direct determination, on the other hand, there exist matrix interference or lack of appropriate calibration standards and chemical reagent. Therefore, it is necessary to hire the separation and enrichment technology in order to improve the sensitivity and selectivity of the determination.Cloud point extraction (CPE) is a new liquid-liquid extraction technology in recent years with the advantages of little uses volatile organic solvents and do not contaminate the environment. It is based on the solubility and cloud point phenomenon of the neutral surfactant micellar in aqueous solution, the hydrophobic and hydrophilic material will separate by changing the experiment parameters. CPE as a mean of separation and enrichment, it has a lot of merits, such as high extraction efficiency, great enrichment factors, easy to operate, convenient to operate, security, economic and convenient for coupling with other instrument. As a result, it takes people's great concern and recognition. Now, it has been widely used in the separation and purification of biological macromolecules, the separation and determination of small organic molecules and the separation and enrichment of metal ions and so on.The purpose of this article is to use the cloud point extraction and hydride generator as a means of separation and enrichment, employ FIA coupled with visible spectrophotometer or AAS as the mean of detection to analysis the speciation of trace chromium, arsenic, lead, cadmium and applied to the actual samples. The main contents of this paper can be summarized as follows:(1) Use the cloud point extraction as a mean of separation and enrichment, hire the FIA-VIS spectrophotometer as a mean of detection, systematically studied the speciation of trace chromium. The optimal extraction conditions and experimental conditions were determined through single-factor experiment and orthogonal test. Under the best conditions, the different forms of chromium in biological samples were analyzed.(2) Use the Flow Injection - Hydride Generator as a mean of separation and enrichment, employ the electrical heating atomic absorption spectrometry as a mean of detection, systematically studied the speciation of trace arsenic. As (III) and As (V) could be separated by controlling the pH value of the solution and explained in theory. Under the optimal conditions, the established method was used in different water samples with satisfactory results.(3) Use the cloud point extraction as a mean of separation and enrichment; use FAAS as a mean of detection, systematically studied a variety of factors of the speciation of trace lead and cadmium, determined the optimal extraction conditions and equipment conditions. Furthermore, it was used in the speciation of trace lead and cadmium in biological samples.