Sensitive and selective ion chromatographic method for the determination of trace beryllium in water samples

A selective and sensitive ion chromatographic method has been developed for the determination of beryllium in a number of water samples at low-μg/l concentrations. The separation was performed on a 250×4.0 mm I.D. iminodiacetic acid functionalised silica gel column. Chromatographed Be(II) was detected using visible detection at 590 nm following post-column reaction with chrome azurol S (CAS). The optimum separation and derivatisation conditions were studied in detail. The optimum eluent conditions were found to be 0.4 M KNO₃, adjusted to pH 2.5 using HNO₃, with optimum post-column detection being achieved using a solution containing 0.26 mM CAS, 2% Triton X-100, 50 mM 2-(N-morpholino)ethanesulfonic acid, pH 6.0. Under the above conditions, the concentration detection limit for Be(II) was found to be 3 μg/l in a standard solution and 4 μg/l in a typical tap water sample, using a 250 μl injection. The method was linear over the investigated range of 10 μg/l to 10 mg/l and highly reproducible. The method was successfully applied to a number of water samples of varying matrix complexity, including simulated seawater, and also to a natural freshwater certified reference material NIST 1640.     

The Spectrophotometric Determination of Sc in Eriochrome Canine R(Chrome azurol s)- Phosphatidl Choline System

Abstract

Eriochrome cyanine R(chrome azurol S) is used as a color reagent to determine Sc in the presence of phosphatidyl choline, σ = 3.7 × 10⁴ (4.5 × 10⁴). This method has been connected to extraction separation to determine Sc in the presence of rare earth elements, and good results have been obtained.

Phosphatidyl choline(PC) is a biochemical reagent, which can be used as a surfactant. It has been reported that chrome azurol S(CAS) can be used to determine Be in the presence of PC¹ but it has not been reported that eriochrome cyanine R(ECR) and CAS can be used to determine Sc in the presence of PC. This paper has put forward a method by which Sc can be determined. ECR (CAB) has been used as a color reagent and PC as a surfactant. Conditional experiments have been made and this method has been connected to extraction separation. Tributyl phosphate (TBP) extracts Sc from rare earth elements to make a determination and good results have been obtained.     

A sensitive spectrofluorimetric determination of human serum albumin with chrome azurol S

A simple and sensitive method for assay of human serum albumin (5–80 μg) is based on binding of chrome azurol S by the albumin and determination of the bound dye spectrofluorimetrically. The method is sufficiently sensitive for application to spinal fluid (20–100 μl).     

高温热水解-离子色谱法测定铬矿中氟含量

建立了一种快速、准确的离子色谱法测定铬矿中氟含量的方法,将铬矿与石英砂混合,控制氧气和水蒸气的流量,于1 100℃高温下热水解30min,水解液经吸收后,选用Dionex AS11-HC阴离子分析柱,以KOH(20mmol/L)作淋洗液,自动再生抑制型电导检测器检测,离子色谱法测定铬矿中氟的含量。方法的检出限为0.022μg/mL,定量限为0.073μg/mL,方法的检测范围为0.0015%~0.20%,加标回收率在92%~101%。应用于实际样品的测定结果表明,铬矿中氟含量的测定值与标准方法的测定值一致。方法简单快速、检出限低、精密度高、准确度好。能满足铬矿中氟含量的快速准确检测要求。     

Spectrophotometric determination of aluminium with chrome azurol s

A comprehensive investigation of the spcctrophotometric determination of aluminium with chrome azurol S is described. No heating is required for colour formation, and the method is considerably more reproducible and selective than either the eriochrome cyanine R or aluminon methods. In the presence of suitable masking agents, only Be²⁺, Zr⁴⁺, and F-cause serious interference. A molar absorptivity of 21,500 at 567.5 mμ was found for the aluminium-chrome azurol S lake, with a relative standard deviation of ± 0.4% at the 20 μg Al level. Beer's law is obeyed from 0 to 1.2 mg Al/ml.     

Spectrophotometric determination of cationic surfactants by formation of ternary complexes with Fe(III) and chrome azurol

An extraction-free spectrophotometric method for the determination of cationic surfactants, such as cetylpyridinium chloride, cetyltrimethylammonium bromide and zephiramine is proposed, which is based on the formation of ternary complexes with Fe(III) and chrome azurol S. The molar ratio of the complex is 2:1:1 (Fe(III):chrome azurol S: cationic surfactant). The method is simple, rapid and sensitive, giving an apparent molar absorptivity of 4.5×10⁴ L·mol^?1-cm^?1 and a linear range of 0.1–6.0 μmol/L cationic surfactants. The total cationic surfactant content can be determined directly in aqueous solutions by measuring the absorbance at 680 nm (pH 5.8). The method has been successfully applied to water samples.     

海洋细菌中铁载体的分离纯化和活性研究

从海洋来源的细菌发酵液中分离得到三个铁载体,其中化合物3为新化合物,化合物1和2为已知化合物nocardamine和schizokinen A。 通过CAS液体检测的方法测定了三个化合物的最低活性浓度,分别为：5, 4 及156μg/mL。     

Chemiluminescence Flow Injection Analysis of Menadione Sodium Bisulfite Based on Luminol Reaction

ABSTRACT

A chemiluminescence(CL) flow system is described for the determination of menadione sodium bisulfite based on its repression on the chemiluminescence(CL) emission produced upon mixing a hexacyanoferrate(III) solution with an alkaline luminol solution in the absence of co-oxidizer. The system responds linearly to menadione sodium bisulfite concentration in the range 0-1 μg/mL with a detection limit (3σ) of 0.01 μg/mL. Relative standard deviation (RSD) of 0.16% for 0.4 μg/mL menadione sodium bisulfite (n=11). The system has been successfully applied to the determination of menadione sodium bisulfite in tablets and injections.     

Determination of Herbicide Difenzoquat Methyl Sulfate in Citruses and Baby Juices by Kinetic‐Spectrophotometric Method and HPLC Method

The purpose of this paper is to present a new kinetic‐spectrophotometric method which involve inexpensive equipment and which can be applied by all analyst who have to determine difenzoquate methyl sulfate (DFQ) residues in citruses and baby juices. The method is based on the inhibited effect of DFQ on the oxidation of sulfanile acid (SA) by hydrogen peroxide in phosphate buffer in presence Cu(II) ion. The reaction was monitored spectrophotometrically by measuring the increase in absorbance of the reaction product at 370 nm. The proposed inhibited method permits determination of DFQ over the range 0.36 to 1.80 μg/mL and 1.80 to 7.20 μg/mL, with quantification limit of 0.184 μg/mL. The relative standard deviations are 0.73‐2.90% for the concentration interval of DFQ 1.80‐0.36 μg/mL. The method was successfully applied to determination of DFQ residues in citruses and baby juices. The HPLC method is used to verify the results. The results obtained for the same samples by the two methods are quite comparable.     

Sensitive spectrophotometric determination of aluminium using thermal lens spectrometry

The determination of Al³⁺ in solution using a continuous-wave mode mismatched thermal lens spectrometer is reported and two spectrophotometric procedures are compared. The reagent investigated were bromopyrogallol red—tetradecyltrimethylammonium bromide (BPR—TDTA) and chrome azurol S—cetylpyridinium chloride (CAS—CPC). The CAS—CPC system gave a superior detection limit (0.17 μg 1^?1) to the BPR—TDTA system (1.15 mg 1^?1) owing to the higher reagent blanks and concomitant laser noise in the latter system.     

Continuous Flow Determination of Carbon Dioxide in Water by Membrane Separation-Chemiluminescent Detection

Abstract

Carbon dioxide has been found to enhance the chemiluminescence of a luminol system. A determination method for carbon dioxide in water was developed by applying this reaction to a continuous flow membrane-separation system. Concentrations of carbon dioxide as low as 0.04 μ g C /mL were determined. Membrane-separation effectively eliminates interferences from Co(II), Cr(III), Fe(III), and other ions which also enhance chemiluminescence. The relative standard deviation for this method was 2.8% (n=5) for 4.0 μ g C /mL and the time required for the analysis of one sample was 3.0 min.     

Kinetic Spectrophotometric Determination of Ranitidine

Two spectrophotometric methods were developed for the determination of ranitidine. The first method was a kinetic spectrophotometric method based on the catalytic effect of ranitidine on the reaction between sodium azide and iodine in an aqueous solution. The calibration graph was linear from 4–24 μg/mL. The drug was determined by measuring the decrease in the absorbance of iodine at 348 nm using a fixed time method. The decrease in the absorbance after 1 minute from the initiation of the reaction was related to the concentration of drug. The detection limit of the procedure was 0.76 μg/mL. The proposed procedure was successfully utilized in the determination of the drug in pharmaceutical preparations with mean recovery in the range of 99.83 ? 101.16%. The second method is a colorimetric method, which depends on the measurement of absorbances of tris (o‐phenanthroline) iron(II) [method 2A] and tris (bipyridyl) iron(II) [method 2B] complexes at 512 nm. The complexes obeyed Beer's law over the concentration range of 2–16 μg/mL and 4–40 μg/mL for methods 2A and 2B, respectively. The developed method has been successfully applied for the determination of ranitidine in bulk drugs and pharmaceutical formulations. The common excipients and additives did not interfere in its determination.     

Flow-injection spectrophotometric determination of aluminium based on chrome azurol S and cetylpyridinium chloride

Acidic aluminium solutions (120 μl) are injected into a buffered (pH 5.7) carrier stream and merge with a chrome azurol S/cetylpyridinium chloride stream; a 2.25-m reaction coil is used with a total flow rate of 4 ml min ^?1. Ethanol (30% v/v) in the reagent stream enhances the absorbance of the ternary complex; the molar absorptivity is then 1.34×10 ⁵ l mol ^?1 cm ^?1 at 625 nm. Calibration is linear over the range 0–400 ng ml^?1 aluminium; the limit of determination is 5 ng ml ^?1. Iron is masked in the usual way; fluoride is tolerated at ˇ1 mg l ^?1. The injection rate is about 45 h^?1. The procedure appears to be applicable to tap water.     

钯(Ⅱ)-泛昔洛韦螯合物与铬天青S相互作用的共振瑞利散射光谱及其分析应用

在pH值为2.5～3.5的Britton-Robinson缓冲溶液中,泛昔洛韦与钯(Ⅱ)相互作用形成1∶1的螯合阳离子,并进一步与铬天青S反应形成1∶1的离子缔合物。该反应可引起共振瑞利散射(RRS)光谱的显著增强并产生新的RRS光谱,最大RRS波长位于367 nm。在一定范围内,共振瑞利散射增强(ΔIRRS)与泛昔洛韦的质量浓度成正比,其线性范围为0.02～2.4 mg/L。该方法的灵敏度高,对泛昔洛韦的检出限为3.6μg/L。实验考察了适宜的反应条件以及共存物质的影响。应用计算化学软件Gaussview3.07和Gaussian03W,采用密度泛函法,在B3LYP/6-31G基组水平上计算了泛昔洛韦的电荷分布,对反应机理和RRS增强的原因进行了讨论。基于Pd(Ⅱ)-泛昔洛韦-铬天青S体系三元离子缔合物的RRS光谱,发展了一种简便、快速、灵敏测定泛昔洛韦的新方法。此方法用于胶囊和尿样中泛昔洛韦的测定,结果满意。     

催化过氧化氢氧化镍-铬蓝黑R络合物光度法测定水体中痕量汞

采用催化过氧化氢氧化Ni(Ⅱ)-铬蓝黑R络合物光度法测定汞,通过优化对比实验,确定最佳反应条件为在pH 4.12的HAc-NaAc缓冲溶液中,以2.00 mL4g/L聚乙烯醇(PVA)作表面活性剂,5.00 mL H_2O_2(1+9)溶液可氧化1.00 mL0.001 mol/L Ni~(2+)溶液与1.00 mL 0.400g/L铬蓝黑R溶液反应生成的Ni(Ⅱ)-铬蓝黑R络合物,75℃水浴加热,汞对该反应具有明显催化作用.在波长571 nm处催化体系和非催化体系的吸光度差值最大.Hg(Ⅱ)在0.1～2.0g/L范围内符合朗格一比尔定律,检出限为3.2×10~(-9)g/L.经实际水体样本论证,本法可用于自然水体中痕量汞的直接测定.     

Catalytic Kinetic Determination of Trace Amounts of Copper with Polarographic Detection

Abstract

This method is based on the catalytic effect of copper(II) on the redox reaction between acid chrome dark blue and ascorbic acid in acetic acid-sodium acetate buffer solution and 1,10-phenanthroline as an activator. Acid chrome dark blue exhibits a sensitive polarographic wave at -0.375V Vs. SCE and change of acid chrome dark blue concentration is traced by a polarographic detection technique. The detection limit and the linear range of copper(II) are 2.34ng/ml and 5 to 50ng/ml respectively. This new catalytic method has been applied to the determination of copper in human hair, with satisfactory results.     

Spectrofluorimetric and Spectrophotometric Determination of Oxamniquine in Pharmaceuticals and Biological Fluids via Derivatization with 4‐Chloro‐7‐Nitrobenzo‐2‐oxa‐1,3‐Diazole (NBD‐Cl)

Spectrophotometric and spectrofluorimetric methods were developed for the determination of oxamniquine (OXM). Both methods are based on coupling with 4‐chloro‐7‐nitrobenzo‐2‐oxa‐1,3‐diazole (NBD‐Cl) in borate buffer of pH 7.6, and the reaction product was measured at 400 nm (Method I). The same product was measured by spectrofluorimetry at 480 nm upon excitation at 400 nm (Method II). The absorbance and the fluorescence intensity were enhanced by addition of sodium dodecyl sulphate (SDS). The absorbance‐concentration plot is rectilinear over the range of 5–25 μg/mL with an LOD of 0.31 μg/mL. The fluorescence‐concentration plot is linear over the range of 0.2–1.2 μg/mL with an LOD of 0.03 μg/mL. Both methods were applied to the analysis of capsules, and the results were in good agreement with those obtained using the official method. The method was applied to spiked human plasma; the mean % recovery (n = 5) is 101.05 ± 1.65. A proposal of the reaction pathway is presented.     

3,4-Dihydroxybenzoic Acid As A Reagent for the Spectrophotometric Determination of Titanium

Abstract

The reaction between titanium(IV) and 3,4-dihydroxybenzoic acid in aqueous media results in an intensely colored complex which is stable for at least 8h. It allows the spectrophotometric determination of titanium in silicate rocks. The proposed method, in pH 4.0–6.0, shows a molar absorptivity of 1.43.10⁴ L.mole^?1.cm^?1 at 380 nm. Beer's Law is obeyed up to 3.0 μg/mL of titanium(IV). The interference of iron(III) can be eliminated by reduction to iron(II) with hydroxylamine hydrochloride. The method was applied to the determination of titanium in various standard rocks and the results indicated that the accuracy and precision are satisfatory.     

Simultaneous Laser Thermal Lens Spectrometric Determination of Trace Platinum and Palladium in an Aquesous Solution

A selective and sensitive method for determination of platinum and palladium(Ⅱ）in an aqueous solution simultaneously by laser thermal lens spectrometry,based on the complex reaction of 2-(3,5-dichloropyridylazo)-5-dimethylaminoamiline(3,5-diCl-PADMA) with platinum and palladium,has been developed.It is shown that the palladium complex can be fromed at room temperature, while the platinum complex can be only formed after being heated in a boiling water bath.By using this difference of reaction temperature and the characteristic of the complexes mentioned above,the method for simultaneous determination of platinum and palladium was established in an aqueous solution without a pre-separation.The results show that the dynamic linear ranges of determination for platinum and palladium are 0.005-0.04μg/mL and 0.005-0.25μg/mL respectively,and that the detection limits are both 0.002/μg/mL.The method has been applied to the determination of platinum and palladium simultaneously in alloy and catalyst samples with satisfactory results.     

Simultaneous determination of seven metal ions in water samples by solid-phase extraction on polyacrylonitrile activated carbon fibres

A new solid-phase extraction method utilising polyacrylonitrile activated carbon fibres (PAN-ACFs) as adsorbent was developed for the preconcentration of trace metal ions prior to their determination by inductively coupled plasma optical emission spectrometry (ICP-OES). The PAN-ACFs oxidised with nitric acid were characterised by FT-IR, XRD, SEM and BET analysis. Then the resulting PAN-ACFs were used as solid-phase adsorbent for simultaneously determination of trace Al(III), Be(II), Bi(III), Cr(III), Cu(II), Fe(III) and Pb(II) ions in aqueous solutions. The influences of the analytical parameters on the recoveries of the studied ions were investigated. The optimum experimental conditions of the proposed method were pH: 6.0; eluent concentration and volume: 3.0 mL of 1.5 mol L^?1 nitric acid; flow rates of sample and eluent solution: 1.5 mL min^?1. The preconcentration factors were found to be 67 for Al(III), Bi(III); 83 for Cr(III), Cu(II), Fe(III) and 50 for Be(II), Pb(II). The precision of this method was in range of 1.5%~3.5% and the detection limit of this metal ions was between 0.06~1.50 μg L^?1. The developed method was validated by the analysis of a certified reference sample and successfully applied to the determination of trace metal ions in water samples with satisfactory results.