Spectrophotometric Determination of U(VI) with Rifampicin in Soil Samples

A validated spectrophotometric method has been developed for the determination of uranyl ion in soil samples. The method is based on the complexation reaction between uranyl ion and rifampicin in methanol‐water medium at room temperature. The method is followed spectrophotometrically by measuring the absorbance at 375 nm. Under the optimized experimental conditions, Beer's law is obeyed in the concentration range of 1.35–20.25 μg mL^‐1 with apparent molar absorptivity and Sandell's sensitivity of 8.0 × 10³ L mol^‐1cm^‐1 and 0.042 μg/cm²/0.001 absorbance unit, respectively. The interference of a large number of anions and cations has been investigated and the optimized conditions developed have been utilized for the determination of uranium(VI) in soil samples. The three sigma detection limit (n = 9) for uranyl ion was found to be 0.20 μg mL^‐1. The proposed method was successfully applied to the determination of uranyl ion in soil samples.     

New Spectrophotometric Method for the Determination of Titanium in Soil and Standard Geochemical Samples

Abstract

In the present communication a simple and rapid spectrophotometric method for the determination of titanium is described. The method is based on the reaction of Ti(IV) with a newly synthesized reagent, 6-(4-nitrophenylazo)-3,4,5-trihydroxy benzoic acid (NATHB), in ethanol medium at pH 3.2 to 4.2. The complex exhibits an absorption maximum at 495 nm and Beer's law is valid over the range of 0.04 – 1.00 μg.ml^?1 Ti. The molar absorptivity is 3.48 × 10⁴ dm³.mole^?1. cm^?1. Most of the foreign metal ions and anions do not produce any colorations with NATHB at selected conditions. Based on these results, a simple and direct spectrophotometric method with high selectivity and sensitivity was proposed. The method has been successfully applied for the determination of titanium in 5 soil and 3 standard geochemical samples.     

高灵敏度分光光度法同时测定钴和铑的研究

新显色剂５－（５－硝基－２－吡啶偶氮）－２，４－二氨基甲苯（５－ＮＯ２－ＰＡ－ＤＡＴ），用作为测定钴和铑的高灵敏度试剂，在５８６ｎｍ处，钴及铑与试剂形成的配合物的吸光度具有很好的加和性。本文利用该试剂与钴，铑显色反应的温度差异，建立了一种高灵敏度光度法同时测定钴，铑的新方法。     

Simple,Rapid, and Sensitive Determination of Thiols by Liquid Chromatography with Fluorescence Detection

Thiol compounds are important for protecting cells from oxidative stress. One common method of quantifying thiols is liquid chromatographic separation with fluorescence detection of their derivatives. The pH and the concentration of tris (2-carboxyethyl) phosphine hydrochloride in the reaction medium were shown to have significant effects on the fluorescence intensity of five thiol compounds: cysteine, glutathione, and three phytochelatins. The optimal pH range for derivatization, as indicated by the maximum fluorescence intensities, was 7.75–8.0 for all of the evaluated thiols. The thiol derivative fluorescence increased and then decreased with the tris (2-carboxyethyl) phosphine hydrochloride concentration. In particular, the fluorescence intensities of all of the derivatives decreased by 96.5–99.9% when tris (2-carboxyethyl) phosphine hydrochloride levels were increased from 0.1 to 1?mmol L^?1. We attributed these changes to preferential interactions between tris (2-carboxyethyl) phosphine hydrochloride and the thiol-specific fluorophore, monobromobimane. We describe herein a method, based on our optimized solution pH and tris (2-carboxyethyl) phosphine hydrochloride concentration, that is rapid (12?min) and boasts excellent recovery (91.3–102%), sensitivity (limit of detections, 17.8–75.2?pmol L^?1) and precision (relative standard deviation values ≤1.03%) for the quantification of these thiol compounds in microalgal samples.     

Spectrophotometric Determination of Copper in Natural Waters and Pharmaceutical Samples with Chloro(Phenyl) Glyoxime

A simple method for the determination of trace amounts of copper by spectrophotometry is described based on the formation of the copper‐chloro‐(phenyl) glyoxime complex. The molar absorptivities of the complexes at pH 4.0 at 290.5 nm were 0.8 × 10⁴l/mol cm. Optimal conditions such as reagent amounts and pH for the copper determination were reported. The effects of the foreign ions were also investigated. The method was successfully applied for determinations of copper in some natural waters and pharmaceutical samples.     

Trace Determination of Copper in Foodstuffs and Biological Samples

Abstract

A new heterocyclic bis-azo dye, 2,6-bis(4-sulfo-1-hydroxy-2-naphthylazo)pyridine, sodium salt (PBS), has been prepared and developed as a sensitive and highly selective chromogenic reagent for spectrophotometric determination of copper. The reagent is found to give a 1:2 (M/L) complex at pH 6.0. Beer's law is followed up to 1.8 ppm with an optimal concentration range between 0.2 and 1.4 ppm. Sandell's sensitivity of the color reaction was calculated to be 0.0013 µg cm^?2 with molar absorptivity of 4.9 × 10⁴ l·mol^?1 cm^?1 at 572 nm. The interfering effects of various cations and anions were also studied. The proposed method was successfully applied to the determination of copper(II) in milk, tea samples, cereals, and legume grains consumed by the Indian vegetarians and in some biological samples. Comparison of the results with those obtained using an atomic absorption spectrophotometer tested the validity of the method.     

A New and Highly Sensitive Spectrophotometric Determination of Monocrotophos in Environmental,Agricultural and Biological Samples

A new and highly sensitive spectophotometric method is developed for the determination of parts per million levels of widely used organophosphorus pesticide monocrotophos. The method is based on alkaline hydrolysis of monocrotophos to N‐methylacetoacetamide followed by coupling with diazotized p‐amino acetophenone in alkaline medium. The absorption maxima of the reddish‐violet coloured compound formed is measured at 560 nm. Beer's law is obeyed over the concentration range of 1.2 to 6.8 μg in a final solution volume of 25 mL. The molar absorptivity and Sandell's sensitivity were found to be 7.1 × 10⁵ (±100) L mole^?1 cm^?1 and 0.008 μg cm^?2, respectively. The standard deviation and relative standard deviation were found to be ± 0.005 and 2.05%, respectively. The method is simple, sensitive and free from interferences of other pesticides and diverse ions. The method has been satisfactorily applied to the determination of monocrotophos in environmental, agricultural and biological samples.     

Rapid and Sensitive Spectrophotometric Determination of Hafuium(IV) With 2-(5-Bromo-2-Pyridylazo)-5-Diethylaminophenol

Abstract

Hafnium(IV) reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in the pH range 3.3–11.0 to yield a sparingly soluble red-coloured chelate that can be dissolved with Triton X-100. Effect of initial pH of metal ion and order of addition of reagents was studied in detail. The 1:3 complex adheres to Beer's law over the concentration range 0.02–1.12 μg/ml of Hf(IV), has a molar absorptivity 1.33x10⁵ 1 mol^?1cm^?1, Sandell sensitivity 1.3 ng cm^?2, formation constant (log K) 11.94 and the method had a relative standard deviation of ± 1.5%. Effect of 60 diverse ions on the determination of hafnium(IV) was studied. This fairly selective method is the most sensitive so far reported for the spectrophotometric determination of hafnium(IV).     

巴比妥酸衍生物荧光增强法快速测定牛奶中的三聚氰胺

建立了一种简单快速测定三聚氰胺的方法. 在pH=7.0的磷酸盐缓冲溶液中, 三聚氰胺与巴比妥酸衍生物(DBA)形成稳定的氢键, 使三聚氰胺的荧光强度显著增强, 由此建立了巴比妥酸衍生物荧光增强测定牛奶中三聚氰胺的新方法. 在优化的条件下, 该方法的线性范围为12.5~1250 μg/L, 检出限为7.5 μg/L, 相对标准偏差为2.06%, 样品平均加标回收率为96.62%. 本方法简便、快速、准确, 可用于大量牛奶样品中三聚氰胺的快速检测.     

牛磺酸与苯醌类试剂的荷移反应

研究了牛磺酸与四氯对苯醌(TCBQ)和2,3_二氯_5,6_二氰_1,4_苯醌(DDBQ)的荷移反应,结果表明,反应均在硼砂溶液中进行,两种络合物λmax值分别是350 nm和340 nm;其组成比均为1∶1;表观摩尔吸光系数ε分别为1.58×104L.mol-1.cm-1和8.40×103L.mol-1.cm-1;比尔定律线性范围分别是1~10 mg/L和0.5~10mg/L;回收率分别为96%~101%和95%~104%;相对标准偏差分别为3.6%和3.1%。应用拟定的方法测定了牛磺酸制剂含量,结果和标准方法一致。     

Study on the Reaction of Proteins with 5＇-Nitrosalicylfluoronemolybdenum（VI） Complex by Spectrophotometry in PVA 124 Microemulsion

The application of 5′‐nitrosalicylfluorone (5′‐NSF)‐molybdenum(VI) complex as a spectroscopic probe was studied. In the buffer medium of HOAc‐NaOAc at 3.45 and in the presence of PVA 124 microemulsion, 5 '‐NSF‐Mo(VI) complex combines protein rapidly to form a stable compound. leading to an absorbance decrease at 525 nrn of 5′‐NSF‐Mo(VI) complex. According to this change, microdetermination of protein has been described. Bovine serum albumin (BSA) could be determined in the linear range of 0–16 pg*mL with the detection limit of 11 ng*mL^?1. Many amino acid and metal ions studied do not interfere with the assay. The method possesses high sensitivity as well as high selectivity. It can be used to determine protein in human urine and milk powder successfully. The relative standard deviations are in all instances less than 4.7%. and the recoveries are between 97.6% and 106.0%. Moreover, the binding number of BSA with the complex, which is determined by using molar ratio, Rosenthal graphic and slope ratio methods, is in good agreement with each other.     

新显色剂1-羟基-2-(5-NO2-2-吡啶偶氮)-8-氨基-3,6-萘二磺酸与铜显色反应的研究

探讨了新显色剂 1-羟基-2-(5-NO2-2-吡啶偶氮)-8-氨基-3,6-萘二磺酸(简称5-NO2-PAH)与铜离子显色的适宜条件及其共存离子的影响,建立了 5-NO2-PAH测定铜的新显色反应体系.在 pH 7.0～10.0 范围内,铜与试剂形成稳定的 1∶2 配合物,其最大吸收峰位于 653 nm, 表观摩尔吸光系数εCu=4.68×104 L·mol-1·cm-1,铜的浓度在 0 μg/10 mL～14 μg/10 mL 范围内遵守比尔定律.方法已用于合金中铜的测定.     

Simple,Selective, and Sensitive Spectrophotometric Method for Determination of Trace Amounts of Nickel（Ⅱ）, Copper （Ⅱ）, Cobalt （Ⅱ）, and Iron （Ⅲ） with a Novel Reagent 2-Pyridine Carboxaldehyde Isonicotinyl Hydrazone

A selective and sensitive reagent of 2-pyridine carboxaldehyde isonicotinyl hydrazone（2-PYAINH） was synthesized and studied for the spectrophotometric determination of nickel, copper, cobalt, and iron in detail. At a pH value of 7.0, 9,0, 9.0, and 8.0, respectively, which greatly increased the selectivity; nickel, copper, cobalt, and iron reacted with 2-PYAINH to form a 1：2 yellow-orange, 1：2 yellow-green, 1：2 yellow and 1：1 yellow complexes, with absorption peaks at 363, 352, 346, and 359 nm, respectively. Under the optimal conditions, Beer＇s law was obeyed over the ranges of 0.01-1.4, 0.01-1.5, 0.01-2.7, and 0.01-5.4 mg/L respectively. The apparent molar absorptivity and Sandell＇s sensitivities were 8.4×10^4, 5.2×10^4, 7.1×10^4, and 3.9×10^4 L·mol^-l·cm^-1, respectively, and 0.00069, 0.0012, 0.00078, and 0.0014 μg·cm2, respectively. The detection limits were found to be 0.001, 0.002, 0.003, and 0.01 mg/L, respectively. The detailed study of various interfering ions to make the method more sensitive was carried out and selective and several real samples were analyzed with satisfactory results.     

新显色剂1-羟基-2-(5-NO2-2-吡啶偶氮)-8-氨基-3,6-萘二磺酸与钯的显色反应

探讨了新显色剂1-羟基-2-(5-NO2-2-吡啶偶氮 )-8-氨基-3,6-萘二磺酸(简称5-NO2-PAH)与钯离子显色的适宜条件及其共存离子的影响,建立了5-NO2-PAH测定钯的新显色反应体系.结果表明,在pH 2.0～5.5范围内,钯与试剂形成稳定的1∶1配合物,其最大吸收峰位于712 nm, 表观摩尔吸光系数ε Pd=2.84×104 L*mol-1*cm-1,钯的浓度在0～20 μg/10 mL 范围内遵守比尔定律.方法已用于实际样品中钯的测定.     

Study on the Determination of Cobalt,Nickel, Copper,Zinc and Vanadium in Environmental Samples by a Rapid High‐Performance Liquid Chromatography

A new method for the simultaneous determination of five transition metal ions in water and food by rapid high‐performance liquid chromatography was developed. The cobalt, nickel, copper, zinc and vanadium ions were pre‐column derivatized with 2‐(2‐quinolinylazo)‐4‐methyl‐1,3‐dihydroxidebenzene (QAMDHB) to form colored chelates, then the Co‐QAMDHB, Ni‐QAMDHB, Cu‐QAMDHB, Zn‐QAMDHB and V‐QAMDHB chelates were enriched by solid phase extraction with a C18 cartridge. The enrichment factor of 50 was achieved by eluting the retained chelates from the cartridge with tetrahydrofuran (THF). These chelates were separated on a ZORBAX Stable Bound rapid analysis column (4.6 × 50 mm, 1.8 um) with 68% methanol (containing 0.1% of acetic acid and 0.1% of CTMAB) as mobile phase at a flow rate of 2.0 mL/min and detected with a photodiode array detector from 450?600 nm. The Co‐QAMDHB, Ni‐QAMDHB, Cu‐QAMDHB, Zn‐QAMDHB and V‐QAMDHB chelates were separated completely within 2.0 min. The detection limits of cobalt, nickel, copper, zinc and vanadium are 2 ng/L, 1.5 ng/L, 2 ng/L, 3 ng/L, and 3 ng/L, respectively, in the original samples. This method was applied to the determination of the five transition metal ions in water and food samples with good results.     

显色剂2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸与钯(Ⅱ)的显色反应研究

研究了显色剂2-(5-羧基-1,3,4-三氮唑偶氮)-5-二乙氨基苯甲酸(CTZDBA)与钯(Ⅱ)的显色反应。结果表明,Pd(Ⅱ)与CTZDBA生成稳定的1∶2的紫红色配合物,其最大吸收波长为548 nm,配合物的表观摩尔吸光系数为9.32×104L.mol-1.cm-1,Pd(Ⅱ)质量浓度在0.08~0.8 mg/L范围内符合比耳定律。该方法可不经分离直接测定钯碳催化剂和钯纳米碳催化剂中的微量钯,测定结果与原子吸收法(AAS)基本相符。     

用2-(4,5-二甲基-2-噻唑偶氮)-5-二甲氨基苯甲酸作显色剂导数光度法同时测定钴和镍

本文研究了用2-(4,5-二甲基-2-噻唑偶氮)-5-二甲氨基苯甲酸(简称DMTAMB)作显色剂,在乙醇介质中,利用一阶导数消除钴(Ⅲ)和镍(Ⅱ)彼此间的干扰,对镍矿石中微量钴和镍进行同时测定,结果满意。     

Study on the Color Reaction of Silver with 2‐(2‐Quinolylazo)‐5‐Dimethylaminoaniline and its Application

A new chromogenic reagent, 2‐(2‐quinolylazo)‐5‐dimethylaminoaniline (QADMAA) was synthesized. A highly sensitive, selective and rapid method for the determination of silver based on the rapid reaction of silver(I) with QADMAA was developed. In the presence of pH = 6.5 sodium citrate‐sodium hydroxide buffer solution and sodium dodecyl sulfonate (SDS) medium, QADMAA reacts with silver to form a violet complex of a molar ratio 1:2 (silver to QADMAA). The molar absorptivity of the complex is 1.26 × 10⁵ L. mol^?1.cm^?1 at 570 nm. Beer's law is obeyed in the range of 0.01–0.6 μg/mL. The relative standard deviation for eleven replicate samples of 0.2 μg/mL silver is 1.76%. This method was applied to the determination of silver in water with good results.     

苯并噻唑偶氮苯甲酸试剂与镍显色反应体系中超分子的作用及其应用

金属离子、有机溶剂、缓冲介质与杂环偶氮苯甲酸类试剂之间存在一定的超分子作用,有机溶剂及缓冲介质的浓度和种类对显色反应的灵敏度有很大的影响。据此,建立了2-(6硝-基-苯并噻唑)偶氮-5二-甲氨基苯甲酸(6-NO2-BTAMB)与镍显色反应新体系。在乙醇存在时,6-NO2-BTAMB在(CH2)6N4-HC l缓冲体系中可与镍形成稳定的蓝绿色络合物,λm ax=650 nm,ε650=1.80×105L.mol-1.cm-1,在0~0.4 mg/L镍范围内符合比尔定律。方法用于纯镁、模拟合金样中微量镍的测定,结果令人满意。