Study And Application Of Determination Of Trace Arsenic(III) By Kinetic Fluorimetry Zhurenhe (Analytical Chemistry)

Arsenic is a human non-essential element which has less toxic,but its compounds are highly toxic, moreover, trivalent arsenic compounds are more toxic than pentavalent arsenic compounds. Arsenic compounds can pollute the atmosphere, soil and water through dust, gas, dust and waste and other forms. The pollution comes mainly from the production and use of the mining, metal smelting, coal combustion, industrial arsenic and arsenic pesticides, semiconductor materials and so on. Therefore, studying of the method is very important for the determination of trace arsenicAt present, several analytical methods have been reported the arsenic detection, but the simple, sensitive and good selective method is not much. Kinetic fluorescence method has the character of high sensitivity, good selectivity and rapid analysis, reporting the determination of arsenic is still relatively small in the environment. In this paper, kinetic fluorescence method for the determination of environmental arsenic was studied and successfully applied in the determination of arsenic. The main research works are described follows:Part 1 Study and Application of Determination of arsenic Method by Catalytic Kinetic Fluorimetry1,Determination of trace arsenite in nature samples using kinetic fluorometryThe trace of As (Ⅲ) has obvious catalysis, which can catalyze the oxidation of acridine orange by KIO3 in hydrochloride medium and make fluorescence quenching. There is a good linearity between the deduction value of fluorescence intensity and the concentration of As(Ⅲ), hence, a novel analytical method was established to detect As(Ⅲ) in nature samples by kinetic fluorometry. The reaction was heated for 11 min in boiling water; the linearity range of this method is 1.0～200μg/L and the detection limit is 0.04μg/L. The method has been already applied to detection of As(Ⅲ) in environmental samples, and the recoveries recovery were between 99.2% and 101.2%.2,Kinetic fluorimetric determination of trace arsenic based on the oxidation of neutral red by potassium iodateA new kinetic fluorimetric method for the determination of trace As (Ⅲ) was developed based on the catalytic effect of As (Ⅲ) on the oxidation of neutral red by potassium iodate in H2SO4 medium, which made the fluorescence intensity decrease. Detailed study the effects of neutral red,potassium iodate,sulfuric acid volume,reaction temperature,time and other conditions on As(Ⅲ) determination. Under optimal conditions, the experiment results indicated that there was a good linearity between the mass concentration of As(Ⅲ) and the value of fluorescence intensity in the range of 2.0 ~ 600μg / L, and the detection limit was 0.6μg/L. it has been used to detection of As (Ⅲ) in environmental water samples with the relative standard deviation less than or equal to 3.5%, and the recovery were between 98% and 101%.3,A novel determination of arsenic method in aqueous samples by kinetic fluorescenceA simple and selective method is purposed for determination of As(Ⅲ) by kinetic fluorometry. The fluorescence intensity of Pyronine B (PB) is decreased by adding some KIO3. Moreover, the fluorescence intensity of PB is further decreased with the presence of As(Ⅲ), due to the PB oxidation by KIO3 with As (Ⅲ) as catalyst was formulated in sulfuric acid medium. There is a good linearity between the fluorescence intensity of PB and the concentration of As (Ⅲ). This method allows for the determination of As(Ⅲ) in the range from 2.0 to 300μg/L, the limit of detection is 1.4μg/L. The method has been successfully applied to the determination of As (Ⅲ) in real samples and the RSD is 2.4% at 100μg/L As (Ⅲ) (n = 11).4,Spectrofluorimetric determination of As (III) in water samplesA novel analytical method for trace As(Ⅲ) determination is described by kinetic spectrofluorimetric, which is based on quenching of the fluorescence, Rhodamine B, by the action of iodine which is released by the reaction between As(Ⅲ) and potassium iodate in acidic medium. Under the optimized conditions, the detection limit is 0.5μg/L, the relative standard deviation is 3.2% for As(Ⅲ) (c= 40μg/L, n=6). The recovery of real As(Ⅲ) samples are in the range of 95.6%～104.1%. The method has been applied for the trace of As(Ⅲ) detection in real water samples. The experiment results point out that there was a good linearity between the fluorescence intensity of Rhodamine B and the concentration of As(Ⅲ).Part 2 Study and Application of Determination of Arsenic Method by Inhibition Kinetic FluorimetryA Study on Inhibition Kinetic Determination of Trace ArsenicIn HCl medium, As(Ⅲ) have obvious inhibition, which can inhibit the oxidation of Safranine T by potassium persulfate, hence, the fluorescence intensity of Safranine T increased. So a new method was developed for determination of As(Ⅲ) by kinetic fluorescence. The reaction was heated for 12 min in boiling water, the linearity range of this method is 10～1600μg /L, and the detection limit is 3.8μg /L. The proposed method has been applied to detection of As(Ⅲ) in environmental samples with the relative standard deviation less than 4.2%, and the recoveries were between 98.5% and 104%.