催化荧光法分析痕量溴的研究

基于在磷酸介质中 ,痕量溴对溴酸钾氧化丁基罗丹明B反应的催化作用 ,建立了痕量溴的催化荧光分析的新方法。方法的检出限为 0 .12 μg·ml-1,线性范围为 0 .80～ 4 .80 μg·ml-1。该方法应用于受污染的河水、硫酸钠及溴吡斯的明药片中溴的分析 ,结果满意     

超痕量铱的催化荧光分析新方法研究

在０．１ｍｏｌ／Ｌ Ｈ２ＳＯ４介质及加热条件下，超痕量Ｉｒ强烈催化ＫＩＯ４氧化罗丹明Ｂ生成一种绿色荧光产物，藉自来水冷却中止反应，研究了催化荧光法测定超痕量铱的影响因素，建立了一个检出限和测定范围分别为０．００５ｎｇ／ｍＬ和０．０１－２ｎｇ／ｍＬ铱的催化荧光分析新方法，并探讨了催化反应的机理。     

催化光度法测定煤矸石中痕量锡

在浓度为０．０５ｍｏｌ／Ｌ的Ｈ３ＰＯ４介质中,痕量锡对ＮａＨ２ＰＯ２还原罗彤明Ｂ９ＲｈＢ）褪色反应有催化作用,褪色速度ｎ含量线性相关,建立了催化吸光光度法测定痕量Ｓｎ的方法。褪色反应随温度同而加快在沸水浴中５ｍｉｎ,△Ａ可达最大值,流水冷却后吸光度保持１２ｈ基本不变,溶液的最大吸收波长为５５５ｎｍ。方法检出限为０．０３５μｇ／Ｌ,吸光度变化ｎ的质量浓度在０～１．０μｇ／５０ｍＬ范围内符合比耳定律。     

痕量间苯二酚的动力学荧光分析

在硫酸介质中,痕量间苯二酚对甲醛催化氯酸钾氧化罗丹明B使其荧光猝灭具有抑制作用,据此建立了动力学荧光法测定痕量间苯二酚的新方法.方法的线性范围为0.016～0.240mg@L-1,检出限为0.009mg@L-1.此法用于自来水样中间苯二酚含量的测定,并进行了加标回收试验,回收率在98%～103%之间.     

催化荧光动力学法测定织物中痕量甲醛

在硫酸介质中，甲醛可以催化溴酸钾氧化罗丹明6G的反应，使其荧光猝灭，据此建立了催化荧光动力学分析法测定痕量甲醛的新方法。方法的线性范围20-160цg/L。该法快速简便，常见易共存有机物干扰小，用于树脂整理特殊织物中痕量甲醛的测定，回收率在96.0%-106.0%之间，结果满意。     

荧光动力学分析法测定痕量鞣酸

基于鞣酸对Cu（Ⅱ）催化过氧化氢氧化罗丹明B具有活化作用，提出了一种简单、高灵敏度的荧光动力学测定痕量鞣酸的新方法。该方法的线性范围为0．04-0．72mg/L;检出限为0．025mg/L.该方法已成功地用于茶叶中鞣酸含量的测定．并与Folin—Ciocalteu光度法作了对照。     

催化荧光法测定痕量锰

本文拟定了一个催化荧光测定痕量锰的新方法。方法检出限为0.0180ng/ml。线性范围为0.04～1.00 ng/ml。直接用于头发、人尿、鱼、水样中锰的测定。回收率为96％～103％,获得满意结果。     

催化动力学荧光法测定痕量培氟沙星

研究了培氟沙星对铜(Ⅱ)催化过氧化氢氧化罗丹明B使其荧光猝灭的抑制作用,据此建立了催化动力学荧光分析法测定培氟沙星的新方法。在最佳实验条件下,方法线性范围为0.2~4.29μg/mL,检出限为0.2μg/L。对实际样品分析,平均回收率为97.6%~101.7%,相对标准偏差为1.03%~1.9%。     

催化荧光法测定超痕量银的研究

基于在乙酸介质中，邻菲罗啉存在下，银对过硫酸钾氧化罗丹明６Ｇ具有催化作用，建立了催化荧光法测定超痕量银的新方法。方法的检出限为５．８０×１０＾－２μｇ／Ｌ，线性范围为２．００￣４０．００ｎｇ／２５ｍＬ。３０多种常见离子基本不干扰测定，将方法用于茶叶、阳极泥、水样中银含量的测定，结果满意。     

食品及生物样品中痕量草酸的荧光动力学法测定

拟定了一个荧光动力学测定痕量草酸根的新方法。在硫酸介质中，草酸催化重铬酸钾氧化罗丹明６Ｇ使其荧光猝灭。方法线性范围为０．８－１４．０ｍｇ／Ｌ，直接用于菠菜，人尿中草酸根的测定，获得满意结果。     

阻抑动力学光度法测定食物中痕量草酸

水果;蔬菜;溴甲酚紫;阻抑动力学光度法测定食物中痕量草酸     

Catalytic Effect of Cetyltrimethylammonium Bromide on the Oxidation of Oxalic Acid by N-Bromophthalimide in Acidic Medium

The kinetics of micellar catalyzed oxidation of oxalic acid [OA] by N-bromophthalimide was studied in the presence of perchloric acid at 308 K. The orders of reaction with respect to [Oxalic acid], [oxidant], and [H⁺] were found to be fractional, first and negative fractional order respectively. Cationic micelles of cetyltrimethylammonium bromide increased the reaction rate. The effect of phthalimide, mercuric acetate and inorganic salts, that is, [Cl^?][Br^?] has also been done. The rate reaction decreases with increasing dielectric constant of the medium. The results are treated quantitatively in terms of Piszkiewicz and Berezin models. The rate constant (K_obs), cooperatively index (n), binding constant (k_s + k_o), and corresponding activation parameters (E_a, ΔH^#, ΔS^#, and ΔG^#) were determined. A suitable mechanism consistent with the experimental finding has been proposed.     

表面活性剂增敏阻抑动力学光度法测定痕量草酸

在稀盐酸介质中，微量草酸对H2O2氧化靛红的褪色反应有显著的阻抑作用，非离子表面活性剂Triton X-100对此体系有强烈的增敏作用，据此建立了表面活性剂增敏阻抑动力学光度分析测定微量草酸的新方法。方法的线性范围是0．005-0．50mg/L，检出限为0．005mg/L。方法简便，快速，灵敏度高，用于菠菜和尿样中草酸含量的测定，结果满意。     

催化动力学光度法测定痕量钯

在磷酸－磷酸二氢钾缓冲溶液中，以钯（Ⅱ）催化次磷酸钠还原罗丹明Ｂ褪色为指示反应，建立了痕量钯的动力学光度分析新方法。在金（Ⅱ）的存在下，检测下限达５×１０＾－１１ｇ／ｍＬ钯（Ⅲ），方法应用于模拟合金样和含钯分子筛中钯的测定。结果满意。     

离子色谱法测定乙醛酸中的顺丁烯二酸和乙二酸

采用抑制电导离子色谱法测定高浓度乙醛酸基体中痕量的顺丁烯二酸和乙二酸。将乙醛酸样品稀释至1 000倍体积后,采用高浓度的淋洗液,以高容量色谱柱对样品进行分析。实验结果表明,顺丁烯二酸和乙二酸最低检出限分别为12.7,19.6μg/L,重现性(n=5)分别为1.13%,1.11%,回收率分别为97.9%,94.7%。该方法具有较高的灵敏度,适用于乙醛酸的例行检测。     

Quantitative Determination of Oxalic Acid Using Victoria Blue B Based on a Catalytic Kinetic Spectrophotometric Method

A sensitive catalytic method is developed for the spectrophotometric determination of oxalic acid. The procedure is based on the effect of oxalate on the oxidation of Victoria blue B by dichromate in dilute sulfuric acid medium. The reaction is quantitatively estimated by measuring the decrease in absorbance of Victoria blue B at the maximum wavelength of 610nm after quenching the reaction with tap water. The factors effecting the sensitivity and reproducibility of the reaction were studied. The method is not interfered with by foreign species generally associated with oxalate and oxalic acid. The described method is simple, specific, inexpensive and suitable for oxalic acid concentrations of between 0.06 and 9.0µgmL^–1. It was validated with satisfactory results by determining oxalic acid content in water extracts from plant materials such as spinach and Lathyrus sativus.     

Hydrolysis Rates of TMOS Catalyzed by Oxalic Acid and Stimulated by Ultrasound

A simple calorimetric method was employed to study the kinetics of the hydrolysis of the solventless TMOS-water mixtures, under ultrasound stimulation, as a function of the concentration of oxalic acid. The reaction rates were obtained, in relative units, from the measured thermal peak of the reaction as a non-separated function of both the sonication time and the instantaneous temperature of the medium. For concentrations of oxalic acid below 0.01 M, polycondensation reaction starts before complete hydrolysis. For concentrations of oxalic acid above 0.01 M, hydrolysis is complete and, in addition, the inverse of the time, as measured from the starting of ultrasound action until the maximum hydrolysis heat release, was found to be a reasonable relative measure of the average hydrolysis rate constant. The average hydrolysis rate constant was found to be proportional to the square root of the molar concentration of the oxalic acid. This result is in agreement with the literature if we assume small dissociation degree for the catalyst in such a solventless alkoxyde-water medium.     

Mechanism of Dealumination of NaY Zeolite with Oxalic Acid

RemovalofalundnumfromNaYzeolitewithacidisanimportantprocessinthemodificationofzeolite.ItisdifficulttoremovealundnumfromNaYzeolitedirectlywithacidwhilekeepinghighcrystallinity.Intheworkreportedhere,alundnumisremoveddirectlyfromNaYwithoxalicacidandthemodifiedzeolitekeepshighcrystallinity.Reactionconditions:CSBlreflux,acidaddedin3ondn,allowedtoreactfor3OAnn.CSB2reflux,acidaddedrapidly,allowedtoreactfor3Owhn.CS2525-C,acidaddedraPidly,allowedtoreactfor3Omin.CSA25"C,acidaddedin3omin,a1lowe…     

麦秆水解-氧化-水解法制取草酸新工艺

研究了以麦秆为原料用水解-氧化-水解法制取草酸的工艺方法。最佳反应条件：麦秆用量50g,硫酸浓度70％,物料浸泡时间≥3h,m(硝酸)：m(麦秆)=2．1：1．0;氧化催化剂V2O5-FeCl3[n(V2O5):n(FeCl3)=1：1]用量0．1g,氧化-水解反应时间5h,反应温度65℃～70℃,草酸二水合物收率75．5％。