Spectrophotometric determination of dissolved organic carbon in some South Island streams and rivers (note)

Absorbance at 360 nm and dissolved organic carbon (DOC) concentration were measured on 47 filtered water samples collected from streams and rivers of the west coast of South Island, New Zealand. The regression equation (DOC (g m^‐3) = 59.6 Abs_{1 cm} + 1.9) calculated from the data, reliably predicted DOC concentration within the range 1.6–43.2 gm^‐3. This relationship is similar to that found fsr some Venezuelan and south‐eastern United Stales waters indicating that it may have widespread utility for estimating DOC concentrations in soft waters where DOC is dominated by humic substances     

Determination of trace vanadium (V) in seawater and fresh water by the catalytic kinetic spectrophotometric method

A new kinetic spectrophotometric method has been developed for the determination of vanadium (V). The method is based on the catalytic effect of vanadium (V) on the oxidation of weak acid brilliant blue dye (RAWL) by KBrO₃ using the citric acid as activation reagent. The obtained optimum conditions are: c (RAWL) = 1×10⁻⁴ molL⁻¹, c (KBrO₃) = 3×10⁻² molL⁻¹, c (citric acid) = 9×10⁻³ molL⁻¹, pH = 2.50, the reaction time being 7.0 min and the temperature being 25.0°C. Under the optimum conditions, the proposed method allows the determination of vanadium (V) in the range of 0–70.0 ng mL⁻¹ and the detection limit is down to 0.407 ng mL⁻¹. For standard vanadium (V) solution determination, the recovery efficiency is in the range of 98.5%–102% and the RSD ranges from 0.76%–1.25%. Moreover, it is demonstrated that most cations and anions do not interfere with the determination of vanadium (V) under the analytical condition. The new method was successfully applied in the determination of vanadium (V) in fresh water and seawater samples with satisfactory results. Vanadium (V) in the seawater samples from Qingdao offshore was determined using the method and the distribution of vanadium (V) was mapped. Compared with other instrumental analytical methods, the proposed method shows good selectivity, sensitivity, simplicity, lower cost and rapidity. It can be employed on shipboard easily.     

氢化物发生-原子荧光光谱法直接测定多金属矿中的硒和碲

用硝酸-氢氟酸-高氯酸分解多金属矿物样品,在6 mol/L盐酸介质中,以Fe3+盐为减缓剂,直接在双道原子荧光光度计上同时测定多金属矿中硒和碲。该方法用同一混合酸一次分解样品,不经分离富集,同时测定硒和碲,过程简单快捷,适合于批量样品的检测。将样品与标准曲线同时分解至冒高氯酸白烟,从而准确地测定多金属矿物样品中硒和碲的含量。方法检出限为硒0.032μg/g,碲0.023μg/g;方法精密度(RSD,n=8)为硒<4.0%,碲<7.0%。经国家一级标准物质GBW 07283、GBW 07233、GBW 07234验证,硒和碲的测定值与标准值吻合。     

痕量锡的催化还原褪色光度法测定

基于０．０２ｍｏｌ／ＬＨ３ＰＯ４介质中痕量Ｓｎ对盐酸联氨还原酸性铬蓝Ｋ褪色反应的催化作用,建立了测定痕量锡的动力学光度分析法。方法检出限０．０３９μｇ／Ｌ,线性范围０￣４．０μｇ／Ｌ。结合磷酸三丁酯色谱分离,对水系沉积物国家标准物质进行分析,结果与标准值相符。精密度试验以ω（Ｓｎ）为１０＾－６水平的试样检测,其ＲＳＤ≤７．２％。     

钯—二安替比林对溴苯基甲烷—钒体系阻抑动力学光度法测定微量钯

在Ｈ３ＰＯ４介质中,微量Ｐｄ（Ⅱ）能阻抑二安替比林对溴苯基甲烷（ＤＡｐＢＭ）与Ｖ（Ⅴ）的显色反应,阻抑程度与Ｐｄ（Ⅱ）量呈线性相关。据此建立了测定微量Ｐｄ（Ⅱ）的新方法。方法检测限为５６．０μｇ／Ｌ,测定范围为０．０～４８０．０μｇ／ＬＰｄ（Ⅱ）。阻抑反应的表观活化能为８６．７２ｋＪ／ｍｏｌ,表观速率常数为５．５７×１０－４／ｓ,反应终止后至少稳定２４ｈ。试样的加标回收率为９１．７％～１０１％（ｎ＝４）。该法用于ｗ（Ｐｄ）在１０－３水平的冶金产品和催化剂中钯的测定,结果与原子吸收法测定结果相符,ＲＳＤ（ｎ＝６）在２．８％～３．３％。     

磁黄铁矿在纳米碳管生长中的作用

本文采用天然磁黄铁矿矿物－六方磁黄铁矿和单斜磁黄铁矿分别作催化剂,引入电弧法生长纳米碳管,发现二者具有截然不同的催化效果。在此基础上,探讨了在合成纳米碳管实验中磁黄铁矿的催化作用及催化机理。     

胶束增溶增敏分光光度法直接测定海水中的硼

首次以含量为１５ ％ 的非离子型乳化剂ＯＰ１００ 胶束体系为介质进行硼的分光光度法测定研究,确定最佳实验条件（ 最大吸收波长为５５５ｎｍ ,姜黄素用量为４ｍＬ,酸试剂用量为５ｍＬ,胶束用量为５ｍＬ,显色温度为５０ ℃,显色时间为１５ｍｉｎ） ,改进了现有的姜黄法,此方法适用于海水中硼的水相直接分光光度测定。实验结果表明测定灵敏度显著增加（Ｅ＝ １ ．５ ×１０５） ,线性范围变宽（０ ～１．２μｇ／２５ｍＬ） ,络合物稳定性好,稳定时间长达５０ｈ。     

二溴羟基苯基荧光酮与铜的显色反应及应用

研究了在混合表面活性剂溴化十六烷基吡啶（ＣＰＢ）及乳化剂ＯＰ存在下,二溴羟基苯基荧光酮（ＤＢＨＰＦ）与铜显色反应的条件。结果表明：在ｐＨ５．４的六次甲基四胺ＨＣｌ缓冲介质中,ＤＢＨＰＦ与铜生成紫色络合物,λｍａｘ＝５３８ｎｍ,ε５３８＝１．６５×１０５Ｌ·ｍｏｌ－１·ｃｍ－１。铜量在０～３６０μｇ／Ｌ符合比尔定律。方法经实际试样验证,结果与原结果相符。对ｗ（Ｃｕ）为０．０４４％～０．３％的样品进行测定,ＲＳＤ（ｎ＝６）为１．７１％～５．５３％。     

水和土壤中微量镍测定的研究

本文研究了PAN-S与镍的显色反应条件。镍与PAN-S反应的最佳pH范围为3.8—9.0。配合物的最大吸收峰位于560nm波长处,表观摩尔吸光系数为3.30×10~4L·mol~(-1)·cm~(-1),25ml试液中镍量在0—1μg/ml范围内服从比尔定律,方法用于水和土壤样品中微量镍的测定,结果良好。