On-line column preconcentration for the determination of cobalt in sea water by flow-injection chemiluminescence detection

A flow-injection method for the determination of dissolved cobalt(II) in sea water has been studied based on a combination of column preconcentration using 8-quinolinol immobilized on silica gel, fluoride containing metal alkoxide glass (8HQ-MAF) and chemiluminescence detection with a gallic acid-hydrogen peroxide system. Co(II) is selectively recovered from an acidified sample with 8-quinolinol immobilized on silica gel. After elution with dilute hydrochloric acid the resultant eluent is mixed with the reagent solutions, heated to 60 ( degrees )C and then introduced into the CL cell. The analysis time including the 2-min sample load was 8 min per sea water sample with a corresponding detection limit of 0.62 ng l(-1) (3sigma). The average standard deviation calculated for 10 replicate measurements of artificial sea water samples with a concentration of 10 ng l(-1) cobalt was +/-2.1%. The method has been tested with the standard reference sea waters NASS and CASS.     

Automated method for the determination of boron in water by flow-injection analysis with in-line preconcentration and spectrophotometric detection

A sensitive, automated method for the determination of boron in water samples is described, involving flow injection with on-line ion-exchange preconcentration and spectrophotometric detection of the azomethine-H—boron complex. The method is applicable to various water samples and is free from interferences, even in coloured samples. Detection limits of 5 μg l^?1 at 20 samples h^?1 and 1 μg l^?1 at 10 samples h^?1 with relative standard deviations of < 10% at 1–10 μg l^?1 and < 5%at 10–200 μg l^?1 levels of boron were achieved. The recoveries for spiked natural water samples ranged from 96 to 101%. The method compares favourably with inductively coupled plasma atomic emission spectrometry.     

Photodegradation and flow-injection determination of simetryn herbicide by luminol chemiluminescence detection

A novel and simple flow injection chemiluminescence method is reported for the determination of simetryn, a common herbicide. The method is based on the direct oxidation of luminol by the photoproducts of the simetryn in alkaline medium in the absence of catalyst/oxidant. The linear concentration range was 0.01 - 2 microg mL(-1) simetryn with a correlation coefficient (r(2)) of 0.9997 and relative standard deviations (RSD; n = 4) in the range of 0.9 - 2.3%. The limit of detection (S/N = 3) was 7.5 ng mL(-1) with a sample throughput of 100 h(-1). The proposed method has been applied to determine simetryn in natural waters using Sep-Pak C(18) cartridges for solid phase extraction (SPE) procedure. The recoveries were in the range of 97 +/- 1 to 104 +/- 2%. The mechanism of chemiluminescence reaction has also been discussed briefly.     

On-line preconcentration and determination of cobalt by chelating microcolumns and flow injection atomic spectrometry

A simple and sensitive flow injection analysis-atomic absorption spectrometric procedure is described for the determination of cobalt. The method is based upon on-line preconcentration of cobalt on a microcolumn of 2-nitroso-1-naphthol immobilized on surfactant coated alumina. The trapped cobalt is then eluted with ethanol (250 μl) and determined by flame atomic absorption spectrometry. The analytical figures of merit for the determination of cobalt are as follows: detection limit (3 S), 0.02 ng ml⁻¹; precision (RSD), 2.8% for 20 ng ml⁻¹ and 1.7% for 70 ng ml⁻¹ of cobalt; enrichment factor, 125 (using 25 ml of sample). The method has been applied to the determination of cobalt in water samples, vitamin B₁₂ and B-complex ampoules and accuracy was assessed through recovery experiment and independent analysis by furnace AAS.     

A simple flow-injection chemiluminescence method for the determination of trace pentavalent vanadium in water samples

A simple method for rapid determination of trace pentavalent vanadium in natural water was presented by flow-injection chemiluminescence (CL). Through water injection, luminol and potassium permanganate were eluted from the anion exchange column to generate the CL, which was enhanced in the presence of V(V). Under the optimum conditions, the increased CL intensity was linear with V(V) concentration in the range from 0.1 to 100?ng?mL^?1. The limit of detection was 50?pg?mL^?1 (3σ) and the relative standard deviation (RSD) was 2.24% (n?=?5) for a 1.0?ng?mL^?1?V(V). At a flow rate of 2.0?mL?min^?1, one cycle of analysis could be performed in 0.5?min with a RSD of less than 3.0%. The proposed method was successfully applied to the determination of vanadium in natural water.     

On-line determination of sulphite in brine by flow-injection analysis

A spectrophotometric flow-injection procedure for the determination of sulphite in aqueous media over the range 0.5–20 mg 1^?1 is described. The reagent used was the organic disulphide 5,5′-dithiobis(2-nitrobenzoic acid). Results are presented for a laboratory-based method for sulphite in water and a potential on-line method for sulphite in high ionic strength potassium chloride brine. The general attractions of flow-injection-based monitors for the on-line analysis of liquid process streams are also discussed.     

Simultaneous determination of tungsten and molybdenum in sea water by catalytic current polarography after preconcentration on a resin column

The simultaneous determination of tungsten and molybdenum in sea water is based on preconcentration by column extraction with 7-(1-vinyl-3,3,5,5-tetramethylhexyl)-8-quinolinol (Kelex- 100) resin, and measurement of the polarographic catalytic currents obtained in a solution of chlorate, benzilic acid and 2-methyl-8-quinolinol. When the concentration factor is 50, the detection limits are 2.4 pM for tungsten and 17 pM for molybdenum (for a signal-to-noise ratio of 3). The precision of the determination is ca. 10% for 67 pM tungsten and ca. 5% for 106 nM molybdenum in sea water (n=4). Results for sea water and other natural waters are presented.     

流动注射化学发光法灵敏检测人血清白蛋白

基于人血清白蛋白(HSA)在碱性介质中对luminol-H2O2化学发光体系有很强的增敏作用,提出了一种流动注射化学发光测定HSA的新方法。在优化条件下,HSA的线性范围为7.5×10-10～2.8×10-7mol/L,检出限为9.1×10-11mol/L,样品检测频率达102个/h。对2.0×10-8mol/L HSA平行测定11次,RSD为0.9%。方法可应用于实际样品人血清中HSA含量的测定。结合化学发光光谱和紫外可见吸收光谱,对该反应机理进行了探讨。     

Trace metal enrichment by automated on-line column preconcentration for flow-injection atomic absorption spectrometry

An on-line column preconcentration technique for flow-injection atomic absorption spectrometry was developed. Diverse metal ions (Cd²⁺, Zn²⁺, Cu²⁺, Mn²⁺, Pb²⁺, Fe³⁺ and Cr³⁺) in solution were concentrated quantitatively by a microcolumn (7-mm × 4-mm i.d.) packed with Muromac A-1, which is an iminodiacetate chelate resin, in a flow-injection system. From the pH dependence of the uptake of the ions, all the divalent metals examined were recovered quantitatively in the pH range 3–5 and the trivalent metals were recovered at a maximum pH of 1. Enrichment factors using 20-ml samples were in the range 90–180-fold for the seven elements and the sampling rate was 13 h^?1. The 3σ detection limits were in the range 0.14–2.1 μg l^?1 and the relative standard deviations for replicate measurements (n=3–4) were in the range 0.7–1.7%. The method was compared with flame and graphite furnace atomic absorption spectrometry. Application to the determination of cadmium and copper in several standard reference materials is described.     

流动注射化学发光法测定盐酸羟苄唑

基于在碱性条件下盐酸羟苄唑能够与鲁米诺产生化学发光的现象,建立了流动注射化学发光测定盐酸羟苄唑的新方法。盐酸羟苄唑的浓度在8×10-7~1×10-4mol/L范围内与化学发光强度呈良好的线性关系,方法的(3σ)检出限为3×10-7mol/L,对1×10-5mol/L的盐酸羟苄唑连续11次测定的相对标准偏差为1.7%,回收率为96%~103%。已用于滴眼液中盐酸羟苄唑的测定。     

Optimization of flow-injection systems for determination of substrates by means of enzyme amplification reactions and chemiluminescence detection

A flow-injection system is described that incorporates a small column reactor containing two co-immobilized, synergistically operating oxidoreductases, allowing determination of minute amounts of substrates by means of enzyme amplification and subsequent chemiluminescence detection of the hydrogen peroxide generated in the repeated redox cycling. With lactate oxidase and lactate dehydrogenase, and taking advantage of the fact that the enzymatic degradation step and the ensuing detection step can be individually optimized, the FIA-system has been optimized by factorial experiments to yield an amplification factor of over 140 for each of the two substrates lactate and pyruvate. With a linear calibration range of 0-6muM, the limits of detection for the two species were 48 and 103nM, respectively, and the sampling rate was 50-60/hr. The optimized system has also been employed for assay of glucose by utilizing a column reactor with immobilized glucose oxidase and glucose dehydrogenase, but yielded amplification factors of only 3-4. The large discrepancy in the performance of the two enzyme systems is discussed.     

A modified nitroso-r method for the determination of cobalt in sea water

The existing colorimetric nitroso-R method for the determination of biologically important cobalt in sea water described by Thompson and Laevastu has been studied in detail, modified and improved. A procedure is recommended in which an approximately five-fold increase in sensitivity is achieved in the measurement of the nitroso-R chelate through close control of : pH, development time of complex, conditions for decomposition of excess reagent, and employment of a wavelength of 425 mμ. The size of the water sample required for an analysis is reduced from 10 to 21. For optimum results it was found necessary for a minimum period of 7 days to elapse following precipitation with sodium carbonate prior to filtration and analysis. A previously unreported salt effect in the procedure is described which requires either construction of a calibration curve from sea water spiked with cobalt or a correction in use of standards in distilled water.A precision was obtained with a 1–2% relative standard deviation throughout range of concentrations used, with an accuracy of 3.0% at 0.5 p.p.b.     

Flow injection ion-exchange preconcentration for the determination of iron(II) with chemiluminescence detection

Summary Flow injection analysis with on-line ion-exchange preconcentration using a mini-column loaded with 8-quinolinol immobilized on controlled-pore glass, is described for the determination of iron(II)-enhanced chemiluminescent oxidation of luminol in alkaline hydrogen peroxide. The detection limit for iron(II) is 10^–13 mol/l (in 3 ml of sample). The operating conditions are optimized, and the effect of interferents is studied. The analysis time was 5 min for each sample, including 2 min for sample loading.     

流动注射化学发光法检测甲醛含量的研究

甲醛能与氨基硫脲反应,从而抑制鲁米诺—氨基硫脲-Au(Ⅲ)体系的化学发光.在优化的条件下,甲醛加入量在0.2～15μg范围与发光强度呈良好的线性关系,方法的检测限为0.1 μg.方法可用于密胺餐具浸泡液中甲醛含量的检测.     

Cyclic flow-injection determination of copper with hexadecyltrimethylammonium bromide micelle-enhanced,fluorescein-sensitized chemiluminescence detection

In the flow-injection system reported, the reagent stream is continuously cycled. The circulating chemiluminescence reagents (β-nitrostyrene/NaOH/hexadecyltrimethylammonium bromide sensitized with fluorescein) allowed 0.1–10 ng of copper(II) to be determined in hundreds of successive injections, even with samples of sea water or a solution of zinc dust.     

脱线柱预富集 ICP-MS法测定南极水样中的痕量元素

采用脱螯合阳离子树脂（D401）将待分析元素预富集并与基体元素分离，采用电感耦合等离子体质谱法（ICP－MS）测定了极拉斯曼丘陵地区环境水样中的难于或不能直接检测的超痕量元素Mn,Co,Ni,Cu,Cd,Ba和Pb；建立了一种准确，简便、快速的在线加内标准方法，被分析元素的测定灵敏度均提高了30倍左右；对于100mL，水样检测限为1．425ng/L-24.84ng/L。     

Use of amino-carbonyl reaction and chemiluminescence detection to the flow-injection determination of some amino acids

Some amino acids were found to react with carbonyl functional groups of humic acid. Products of this reaction give strong chemiluminescence during their oxidation with N-bromosuccinimide (NBS) in alkaline solution. Humic acids from different sources produced similiar signal magnitude. This effect was employed to the flow-injection determination of glycine and arginine in pharmaceutical formulations with considerable selectivity against different amino compounds. The proposed method is fast and simple. Detection limit is 0.20 and 0.25 mg.l(-1) for glycine and arginine respectively, and 115 samples per h can be determined.     

反向流动注射化学发光法测定马来酸氯苯那敏

基于马来酸氯苯那敏对KIO4-鲁米诺化学发光体系有强的增敏作用,结合反向流动注射技术,建立了测定马来酸氯苯那敏的化学发光分析方法,在优化的条件下,测定马来酸氯苯那敏的线性范围为7.0×10-8~1.0×10-4g/mL,检出限为3×10-8g/mL,对质量浓度为9.0×10-7g/mL的马来酸氯苯那敏进行11次平行测定,其相对标准偏差为1.5%,方法已用于扑儿敏片剂和人体尿液中马来酸氯苯那敏的含量测定。     

On-line separation and preconcentration of trace cadmium in environmental water samples by micro column filled with modified nanometer Si-HAP prior to FAAS determination

A novel method of on-line solid phase extraction (SPE) preconcentration has been established for the determination of cadmium in environmental water samples by flame atomic absorption spectrometry (FAAS). The method is based on the on-line retention of cadmium on a micro column of nanometer Silicon Hydroxyapatite (Si-HAP) modified with 1-phenyl-3-methyl-4-bonzoil-5-pyrazone (PMBP) and subsequent elution with 1.0?M thiourea and determination by FAAS. The effect of various parameters that could affect the performance of the system was investigated. The enrichment factor (EF) for cadmium (II) was 250. The limit of detection (LOD) obtained under optimum conditions was 0.28?µg?L^?1 and the relative standard deviation (RSD) for seven replicates at 100?µg?L^?1 Cd²⁺ concentration level was 1.4%. The method was applied to water samples and standard reference materials. The accuracy was assessed through recovery experiments and comparing the results with the accepted values of standard reference material.     

Anion-exchange separation and spectrophotometric determination of cobalt in sea water

Summary Traces of cobalt in sea water have been preconcentrated by anion-exchange from acidified sea water in the presence of thiocyanate. Cobalt adsorbed on the resin column is stripped by elution with 2 M perchloric acid. Accompanying iron is removed subsequently by anion-exchange from 6 M hydrochloric acid medium. Cobalt in the eluate is determined spectrophotometrically with 4-(2-pyridylazo)resorcinol in the presence of EDTA and potassium cyanide. The anion-exchange — PAR method allows to determine cobalt very selectively in sea as well as non-saline waters on a 2 l sample basis. The method gives a coefficient of variation of ca. 10% at a cobalt level of 0.1–0.2 g per liter.

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Spektralphotometrische Bestimmung von Kobalt in Meerwasser nach Abtrennung durch Anionenaustausch

Zusammenfassung Kobaltspuren in Meerwasser wurden angereichert durch Behandlung des angesÄuerten Wassers mit einem stark basischen Anionenaustauscher in Gegenwart von Thiocyanat. Adsorbiertes Kobalt wird mit 2 M PerchlorsÄure abgelöst. Eisen wird anschlie\end durch Anionenaustausch aus 6 M salzsaurer Lösung entfernt. Kobalt wird im Eluat spektralphotometrisch mit 4-(2-Pyridylazo)resorcin in Gegenwart von ÄDTA und KCN bestimmt. Das Verfahren gestattet eine selektive Kobaltbestimmung in Meerund Sü\wasser bei Verwendung von 2 l-Proben. Der Variationskoeffizient betrÄgt etwa 10% bei 0,1–0,2 g Co/l.