Application Of Catalytic Spectrophotometry In Environment Analysis

Catalytic spectrophotometry method is a useful technique in the determination of trace substances. It enjoys great generality in most laboratory for its high sensitivity and inexpensive instruments. Analysts combined the technique of flow injection with catalytic method, which compensated many drawbacks when traditional catalytic spectrophotometric is adopted such as high regeant cost, inconvenient control of analysis condition and low analysis speed, and which greatly promoted the development of catalytic speetrophotometric method.There are two parts in this thesis:Part one: reviewThe new development of traditional catalytic speetrophotometric method during last senve years, among which new approches, new system, performance enhancement and so on are exploited.The new development of flow-injection catalytic speetrophotometric method.Part two: study reportsA new catalytic spectrophotometic method is proposed for the determination of cobalt(Ⅱ), based on the fact that cobalt(Ⅱ) can catalyze the discolouring reaction of Orange G oxidized by hydrogen peroxide in NH3-NH4Cl buffer solution medium. Under the optimum experimental conditions, the linear range of the determination is 0.006～2.0μg/25mL and the detection limit of 3.41×10-3μg/25mL. The proposed method is applied to the determination of trace amounts of cobalt(Ⅱ) in Vitamin B12 with satisfactory results.A new inhibition discoloring spectrophotometric method for determination of antimony(Ⅲ) is described. This method is based on the innibitic effect of antimony(Ⅲ) on the reaction of Orange G and hydrogen peroxide in the NH3-NH4Cl buffer solution medium. The linear range of the determination is 0.10～5.50μg/25mL for antimony(Ⅲ) and the detection limit is 6.36×10-4μg/mL. The method has been applied for the determination of antimony(Ⅲ) in water sample with satisfactory result.A new flow-injection-inhibition discolouring spectrophotometric method using stopped-flow technique for determination of trace antimony(Ⅲ) is described. This method is based on the catalytic effect of antimony(Ⅲ) on the reaction of Malachite Green and hydrogen peroxide in the Britton-Robinson buffer solution medium. The linear range of the determination is 0.01～2.0μg/mL for antimony(Ⅲ) with a correlation coeffient of 0.9996, and the detection limit is 7.8×10-3μg/mL with the sampling rate of 22.8 times per hour. The relative standard deviation of eleven replicate measurements is 0.97% for 0.1μg/mL. The method has been applied for the determination of trace antimony(Ⅲ) in water sample with satisfactory result. The recovery is 97.3～97.7%.A new reverse flow-injection inhibition discoloring spectrophotometric method using stopped-flow technique for determination of ultra trace bismuth(Ⅲ) is described. This method is based on the innibitic effect of bismuth(Ⅲ) on the reaction of Malachite Green and hydrogen peroxide in the Britton-Robinson buffer solution medium. The linear range of the determination is 0.001～0.54ng/L for bismuth(Ⅲ) with a correlation coeffient of 0.9992, and the detection limit is 9.9×10-4ng/L with the sampling rate of 20.9 times per hour. The standard deviation of eleven replicate measurements is 1.3% for 0.001ng/L bismuth(Ⅲ). The method has been applied for the determination of ultra trace bismuth(Ⅲ) in human hair and water sample. The recovery is 96.0～102.0%.A new reverse flow-injection inhibition discoloring spectrophotometric method using stopped-flow technique for determination of bismuth(Ⅲ) is described. This method is based on the innibitic effect of bismuth(Ⅲ) on the reaction of Crystal Violet and hydrogen peroxide in the H2BO3-KCI-NaOH buffer solution medium. The linear range of the determination is 0.005～0.05μg/mL for bismuth(Ⅲ) with a correlation coeffient of 0.9998, and the detection limit is 7.28×10-4μg/mL with the sampling rate of 21.8 times per hour. The standard deviation of eleven replicate measurements is 0.45% for 0.01μg/mL bismuth(Ⅲ). The method has been applied to the determination of bismuth(Ⅲ) in bismuth aluminate compound table. The recovery is 101.5%.