邻苯二酚紫-示波计时电位法测定天然水中不同形态铝

报道邻苯二酚紫-示波计时电位法分别在酸性和碱性条件下直接检测天然水中的无机单核铝和总单核铝浓度。并用该法测定了水样中的总铝,有机单核铝和酸溶态铝,从而实现了天然水中5种Al形态的电化学测定。测定了20多个实际水样,与Driscoll方法进行了对照,结果基本一致。     

邻苯二酚紫-溴化十六烷基吡啶分光光度法测定钢中钼

常用的硫氰酸盐光度法测定钢中钼灵敏度较低。对微量钼且须富集或萃取。近年来,对阳离子表面活性剂存在下,邻苯二酚紫光度法测定钼已有报导。本文采用在溴化十六烷基吡啶(CPB)存在下,邻苯二酚紫(PV)分光光度法直接在水溶液中测定钼。并用抗坏血酸(AK)、KF-EDTA掩蔽共存元素的干扰。对六种含钼量为0.005-0.56％的普碳钢及低合金钢标样测定均获得满意结果。本方法钼浓度在25—150微克/50毫升范围内符合比尔定律,比现行的硫氰酸盐光度法更为快速、灵敏、简便,适于测定普碳钢及低合金钢中钼的含量。 1.主要试剂:(1)10％AK(现用现配);     

Zn—EDTA掩蔽Fe（Ⅲ）用CAS光度法测定硅铁中铝

络天青S(CAS)光度法早已应用于硅铁中铝的测定,但需用铜铁试剂沉淀分离铁、钒、钛、锡等干扰元素,不适合工厂快速分析。本文参考文献[2],采用不分离干扰元素,在弱酸性介质中用Zn-EDTA掩蔽Fe(Ⅲ),用CAS光度法测定硅铁中铝。分析结果能达到国家允许差的要求,方法简便、快速,可应用于各种牌号硅铁中铝的快速测定。     

双波长分光光度法同时测定灌木饲料中的铁和铝

利用铁、铝与邻苯二酚紫（PCV）形成的络合物的最大吸收波长相差30nm的光谱性质，建立了同时测定铁和铝的双波长分光光度法，并对络合物的形成条件及相互干扰情况进行研究，方法用于灌木饲料样品中铁和铝测定。     

氧化氩氮-乙炔火焰原子吸收光谱法测定钛铝钒合金中铝

铝常用的测定方法有碱分离-EDTA络合滴定法、氟化钠分离-EDTA容量法、络天青S光度法、铜铁试剂分离-络天青S光度法、络天青S-氯化十六烷基吡啶光度法、偶氮氯膦Ⅰ光度法、苯甲酸铵分离-EDTA络合滴定法、氢氧化钠分离-六氟铝钾沉淀酸碱滴定法、原子吸收光谱法等。铝作为强抗氧化剂加入到钛铝钒合金中，具有细化晶粒、改善抗氧化和耐腐蚀性能的作用，但多了会对性能造成不良影响。因此必须对原材料中铝的量严格控制。化学法测定钛铝钒合金中铝含量，缺点是使用的试剂种类多，而且方法比较复杂繁琐，不便于掌握。用火焰原子吸收光谱法测定钛铝钒合金中铝，方法简单、快速、易于掌握、同时测定、精确度高，能满足原材料复检过程中分析的需要。     

铬天青S分光光度法测定食物中铝时高氯酸根的干扰及其消除

研究了铬天青S分光光度法测定铝时,样品消化液中残留高氯酸根的干扰及其消除方法,用阴离子交换树脂将样品消化液中残留的高氯酸根交换去除。结果表明,样品经过阴离子交换树脂柱后,高氯酸根基本去除,不再产生混浊,且铝的回收率达90%。该法简便可行,提高了铝测定的准确度。     

氯仿萃取8-羟基喹啉荧光法测定天然水中的总单核铝和酸溶态铝

采用氯仿萃取８－羟基喹啉荧光光度法（８－ＨＱ－ＣＬ－ＭＦ）测定了天然水样中的总单核铝和酸溶态铝含量,与Ｄｒｉｓｃｏｌｌ的甲基异丁基酮萃取８－羟基喹啉－石墨炉原子吸收法（８－ＨＱ－ＭＩＢＫ－ＧＦ／ＡＡＳ）法进行了比较,结果一致。本法具有取样量小,检测快捷,灵敏度高,重现性好等突出优点,合适于天然水中的总单核铝和酸溶态铝的分析。研究了滤膜过渡,酸消化以及紫外酸消化对天然水中铝形态测定的影响。     

铝矾土中三氧化二铝含量的快速测定——以苦杏仁酸隐蔽钛络合滴定铝

以往有钛存在下滴定铝未获成功,因尚未找到能隐蔽钦的适当试剂。因此,有建议以铜铁试剂沉淀铁和钛或以铜铁试剂-氯仿萃取分离铁和钛,然后作铝的滴定。有提出测定高铝耐火材料中的铁铝钛是在 pH 1.5滴定铁,继加入过氧化氢在 pH 5.5滴定钛铝合量,再用过氧化氢比色法测定钛,从钛铝合量减去钛量才得铝量。这些方法都比较繁复。我们曾发现乳酸和苹果酸对钛有很强的络合能力,均能隐蔽钛     

紫尿酸树脂相光度法测定痕量铁

树脂相光度法属于固相光度法,由于该法集分离富集于一体,因而具有较好的选择性及较高的灵敏度,已应用于多种金属离子的定量分析。以邻二氮菲为显色剂的树脂相光度法测定铁文献[3]也有报道。本文根据碱性条件下Fe(Ⅱ)与紫尿酸(VA)可形成稳定的蓝色配阴离子的原理,以苯乙烯型强碱性阴离子交换树脂吸附铁的配阴离子,在620nm测定树脂相的吸光度,建立了文献未见报道的痕量铁的紫尿酸树脂相光度测定法,方法线性范围为Fe(Ⅱ)0～25.0μg/29ml,其灵敏度约为水相光度法的10倍,方法用于自来水中铁的测定,结果令人满意。     

CAS-CPB胶束增溶光度法直接测定金红石单矿物中铝

一般矿石中微量铝采用CAS光度法测定,用酒石酸或苦杏仁酸掩蔽钛的干扰,TiO_2的允许量最多达250微克。金红石含TiO_295%左右,所以直接测定其中的铝是困难的。CAS-CPB胶束增溶光度法测定铝比CAS的灵敏度高,但钛的干扰严重,经试验用酒石酸掩蔽钛,存在0.5毫克TiO_2就有明显正干扰,1毫克TiO_2使吸光度增加1倍;采用酒石酸—苦杏仁酸联合掩蔽效果较好,1.5毫克TiO_2基本无影响,但灵敏度有所降低,摩尔吸光系数为8.5×10~4,仍比CAS灵敏度高,可不经分离直接光度法测定金红石单矿物中的微量铝。     

Speciation of aluminium(III) in natural waters using differential pulse voltammetry with a pyrocatechol violet-modified electrode

A differential pulse voltammetric (DPV) procedure is proposed for the speciation of aluminium in natural waters using Pyrocatechol Violet chemically modified electrodes (PCV-CMEs). This novel speciation idea is based on the selective determination of different AlIII forms under two pH conditions. The labile monomeric Al fraction (mainly inorganic Al) is analysed at pH 4.8 (0.20 mol dm(-3) NaOAc-HOAc) and the total monomeric Al fraction is analysed at pH 8.5 (0.20 mol dm(-3) NH3.H2O-NH4Cl). The difference is thought to be caused by the weak competition ability of PCV to sequester AlIII from AlIII-natural organic matter complexes. This sensitive and simple speciation method has been applied successfully to aluminium speciation in natural waters sampled from different regions of China. Five fractions are measured directly or indirectly: (i) labile monomeric Al; (ii) total monomeric Al; (iii) acid reactive Al; (iv) non-labile monomeric Al; and (v) acid soluble Al. The results are in satisfactory agreement with those obtained by Driscoll's 8-hydroxyquinoline extraction-ion exchange method.     

酸性媒染紫—示波计时电位法测定天然水不同形态铝

本文报道酸性媒染紫（SVRS）一示波计时电位法测定天然水中不同形态铝。对24个实际水样分别在酸性pH5.2测定了无机单核铝Ali和碱性pH8.8底液中测定总单核铝Ala,有机单核铝Al0-Ala-Alio同时还应用该法测定了酸化水样中总铝AlT,酸溶态铝AlT=AlT-Ala,从而实现了水样中五种形态铝的电化学测定,测定值与Driscoll方法进行了比较对照,结果基本一致。本法特点为：简便快捷,灵敏准确,可以直接测定与铝毒性密切相关的无机单核铝Ali,无需分离步骤,水样用量小,适用于大批量天然水样中Al形态的快速分析。     

Use of flow injection multisite detection as a novel approach for blank signal correction in a spectrophotometric determination

A flow injection multisite detection system was developed for correction of the sample blank in a colorimetric determination. By using detector relocation, a single spectrophotometer is used for the sequential reading of the sample blank and of the colored product; the sample crosses the flow cell to measure intrinsic absorption, the color reagent is subsequently added, and the flow cell is relocated to provide the reading of the resulting plug. The subsequent detector relocation immediately after peak maximum increases the determination frequency. This strategy was tested in the colorimetric determination of iron in soil samples based on the reaction of Fe (II) with 1,10-phenanthroline after reduction of Fe (III) to Fe (II) by ascorbic acid. The results obtained for 15 soil extracts were in good agreement with those obtained by the reference procedure. Relative standard deviations better than 4% were obtained, with a sampling rate of 30/h.     

Spectrophotometric determination of beryllium in air and dust

The requirements of beryllium monitoring are discussed. Emphasis is placed on developing an Analytical procedure which is rapid, simple to operate, of adequate sensitivity and of reasonable accuracy. For air analysis, beryllium bearing dust is collected on a membrane filter, the beryllium is obtained in solution and determined spectrophotometrically, using aurine tricarboxylic acid (aluminon) as reagent Interference due to other metals is avoided by the addition of suitable complexing agents. A sensitivity of 0 1 μg Be can be achieved     

Ion exchange chromatography of aluminum using 3-carboxy-2-naphthylamine-N,N-diacetic acid as a fluorescent post-column chelating reagent

Ion exchange chromatography of aluminum ion using 3-carboxy-2-naphthylamine-N,N-diacetic acid (CNDA) as a fluorescent post-column chelating reagent was studied. The solution containing ammonium chloride and hydrochloric acid was used for the eluent, and acetate buffer solution containing CNDA was used for the post column chelating reagent. The peak of aluminum was separated from that of calcium, magnesium and zinc, and the chromatogram was not affected by copper(II) and iron(III). The calibration curve gave linear plots with a range of 0.0027-0.54 ppm aluminum, the regression coefficient of correlation (r2) was 1.000, and the detection limit (S/N = 3) was 0.3 ppb, indicating that the method could determine aluminum with high sensitivity. It was demonstrated that CNDA is a useful metallofluorescent reagent for aluminum. This method has been successfully applied to the determination of aluminum in some tea drinks.     

Blister-colorimetric determination of phosphate ions in water,agricultural samples,and biological samples

A procedure was proposed for the determination of phosphate ions in a blister cell (pellet cartridge) with a dry reagent mixture. The procedure is suitable for the quantitative determination of phosphate in different samples using a dry reagent mixture in an ampule or a blister without dissolving the reagents. After an ampule or a blister cell was opened and several drops of a test liquid were added, a color developed, whose intensity was proportional to the concentration of phosphate ions in the solution. The solution was then diluted to 2 mL with water and analyzed by photometry. The composition of the mixture was determined, and the procedure for the quantitative determination of phosphate ions was proposed; the procedure involves the formation and reduction of phosphomolybdic acid and the use of auxiliary reagents. The error of the colorimetric determination of phosphate ions in aqueous solutions, soil extracts, and urine was estimated with the participation of inexperienced operators.     

Microdetermination of magnesium in biological fluids

A modified procedure for the spectrophotometric determination of serum magnesium is described in which a direct addition of serum is made to a two-piece color reagent system. One solution contains an optimized concentration of the color reagent Magon, 1-azo-2-hydroxy-3-2-(2,4-dimethylcarboxanilido)-naphthalene-1′-(2-hydroxybenzene-5-sulfonate) sodium salt, in a dimethyl sulfoxide medium for binding magnesium and also EGTA, ethylene-bis(oxyethylenenitrilo)-tetraacetic acid, for binding calcium. The other is an alkaline solution of dilute cyanide to bind copper and iron and provide the optimum reaction pH. By means of these ingredients the simple procedure involves a reaction with serum magnesium while masking the interference of calcium and trace metals and allowing the reaction to take place without either separation or deproteinization steps. Optimized characteristics are shown for a linear reaction involving a variable reaction blank in the procedure where calcium is measured against a blank that is constant in its makeup. The linearity of the procedural reagent blank, with respect to its own concentration, helps attain the required linear results for the overall system and this is described by spectral studies.     

Novel bimodal porous N-(2-aminoethyl)-3-aminopropyltrimethoxysilane-silica monolithic capillary microextraction and its application to the fractionation of aluminum in rainwater and fruit juice by electrothermal vaporization inductively coupled plasma mass spectrometry

A novel bimodal porous N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (AAPTS)-silica monolithic capillary was prepared by sol–gel technology, and used as capillary microextraction (CME) column for aluminum fractionation by electrothermal vaporization inductively coupled plasma mass spectrometry (ETV)–ICP–MS with the use of polytetrafluoroethylene (PTFE) slurry as fluorinating agent. The extraction behaviors of different Al species were studied and it was found that in the pH range of 4–7, labile monomeric Al (free Al³⁺, Al–OH and Al–F) could be retained quantitatively on the monolithic capillary, while non-labile monomeric Al (Al–Cit and Al–EDTA) passed through the capillary directly. The labile monomeric Al retained on monolithic capillary was eluted with 10 μL 1 mol L^− 1 HCl and the elution was introduced into the ETV for fluorination assisted ETV–ICP–MS determination. The total monomeric Al fraction was also determined by AAPTS-silica monolithic CME–fluorination-assisted electrothermal vaporization (FETV)–ICP–MS after the sample solution was adjusted to pH 8.8. Non-labile monomeric Al was obtained by subtracting labile monomeric Al from the total monomeric Al. Under the optimized conditions, the relative standard deviation (R.S.D) was 6.2% (C = 1 μg L^− 1, n = 7; sample volume, 5 mL), and the limit of detection was 1.6 ng L^− 1 for Al with an enrichment factor of 436 fold and a sampling frequency of 9 h^− 1. The prepared AAPTS-silica monolithic capillary showed an excellent pH tolerance and solvent stability and could be used for more than 250 times without decreasing adsorption efficiency. The developed method was applied to the fraction of Al in rainwater and fruit juice, and the results demonstrated that the established system had advantages over the existing 8-hydroxyquinoline (8-HQ) chelating system for Al fractionation such as wider pH range, higher tolerance of interference and better regeneration.     

On the detection of aluminium by means of aluminon

The well-known reaction of aluminium with aluminon has been modified in such a way as to make it specific for this element. This has been accomplished by adding sulphurous acid beforehand and ethanol and hydrochloric acid afterwards. Thc first reagent prevents the interference of chromium, indium, gallium, and titranium; the second those of beryllium, scandium, zirconium and small amounts of ferric iron.