曙红Y褪色光度法测定微量铈

研究了在氨-氯化铵介质中Ce(Ⅳ)催化高碘酸钾氧化曙红Y的褪色反应及其动力学条件,测定了反应级数和表观活化能,建立了测定痕量铈的新方法。曙红Y的最大吸收波长为515 nm,该方法的检出极限为2.0×10-10g.ml-1,线性范围为0~400 ng.ml-1,可用于发样中痕量铈的测定。

曙红B催化动力学光度法测定痕量铋(Ⅲ)

在硫酸介质中,铋(Ⅲ)对碘酸钾氧化生物染料曙红B的褪色反应有强烈的催化作用,据此建立了测定痕量铋(Ⅲ)的催化动力学新方法。体系催化反应吸光度(A)和非催化反应吸光度(A0)的变化值(ΔA)与铋(Ⅲ)浓度在0.2～1.2 mg/L范围内呈良好的线性关系。方法检出限为7.22×10-11 g/L,表观速率常数为2.97×10-4 s-1,表观活化能为36.74 kJ/mol。将该法用于水体中痕量铋(Ⅲ)的测定,结果满意,回收率为98.5%～104.2%。

阻抑动力学光度法测定蔬菜中的抗坏血酸

A new method for the determination of ascorbic acid by the kinetic spectrophotometry was established,based on the inhibitory effect of trace ascorbic acid on the reaction of Bromeosin Y with KIO4 catalyzed by Ce(Ⅳ) in the medium of H2SO4.The influence of acidity,amounts of reagents,temperature and other factors on the reaction were discussed.The optimum conditions of the reaction and some kinetic parameters were determined.The apparent energy of the catalyzed and the inhibited reaction were 35.60 kJ·mol and 69.89kJ·mol respectively.The linear range was 0.02μg·mL-1～1.6μg·mL-1 of ascorbic acid,and the detection limit was 0.011μg·mL-1.The proposed method has been applied successfully to the determination of trace ascorbic acid in various vegetables with the results corresponding to that obtained by the iodimetry.

Ti(Ⅳ)-Brˉ-HFInBr_4悬浮物光度法测定痕量钛(Ⅳ)

基于Ti(Ⅳ)能与曙红、溴离子形成可溶于乙醇的悬浮物,据此建立了悬浮物光度法测定痕量Ti(Ⅳ)的新方法。该悬浮物表观摩尔吸光系数ε530值为2.54×107L·mol-1·cm-1,线性范围为1～100ng/mL,检出限为8.2×10-9g/L。本法用于发样中Ti(Ⅳ)含量的测定,结果满意。

曙红荧光猝灭法测定水中ClO_2

在pH值为5.0的HAc-NaAc缓冲溶液中,曙红在540 nm处产生一个荧光峰,并能被C lO2氧化导致其荧光发生猝灭。通过试验确定了C lO2使曙红褪色的最佳条件,C lO2在0.042 mg/L^0.916 mg/L范围内与曙红荧光猝灭强度呈线性关系,据此建立了水中C lO2的荧光分析方法,方法检出限为0.01 mg/L。

催化动力学光度法测定铜离子

在Ｈ２ＳＯ４ 介质中， 氯酸钾可以氧化曙红而使其褪色， Ｃｕ２ ＋ 对此反应具有催化作用， 从而建立了测定Ｃｕ２ ＋ 的新方法． 测定的线性范围为０－５ ～２０μｇ／Ｌ， 检出限为０－２２μｇ／Ｌ．