Determination of peroxidase encapsulated in liposomes using homogentisic acid y-lactone chemiluminescence.

Homogentisic acid gamma-lactone (HAL) chemiluminescence (CL) was applied to the determination of horseradish peroxidase (HRP) encapsulated in liposomes. HRP was detected after the lysis of HRP-trapped liposomes with Triton X-100. CL response rate, detection limit and linear range of calibration curve for HRP in HAL CL were compared with those in piodophenol (p-IP)-enhanced luminol CL. Maximal light emission in HAL CL appeared more rapidly compared to that in p-IP enhanced luminol CL, thus resulting in remarkable reduction of CL measurement time. The detection limit for HRP in HAL CL was the same as that in p-IP-enhanced luminol CL. The linear range of calibration curve for HRP in HAL CL was improved by a factor of 50 compared with that in p-IP-enhanced luminol CL. From these results, it was found that HAL CL were superior to p-IP-enhanced luminol CL for the determination of HRP encapsulated in liposomes.     

Determination of small amounts of mercury

A number of methods for the determination of trace amounts of mercury are reviewed with emphasis on sensitivity and ease of application.     

Determination of small amounts of boron by radiation decomposition of chloroacetic acid solution

For the determination of boron in the mug/g range in aqueous solution by activation analysis an indirect method is proposed, based on the liberation of chloride ions from chloroacetic acid by the primary reaction (10)B(n, alpha)(7)Li. The sample solution, to which is added 0.01-0.5M choroacetic acid, is irradiated with reactor neutrons. The concentration of the chloride ions liberated from the chloroacetic acid is directly proportional to the boron content of the irradiated sample. It is determined potentiometrically with a chloride-sensitive electrode. By this method boron contents >/= 10(-5) g can be detected with good reproducibility. Interference from other ionic species has been investigated and can be neglected. The method is suitable for the determination of boron in biological matrices.     

Indirect determination of micro amounts of medicinal drugs by atomic-absorption spectrometry-measurement of L-ascorbic acid

Summary Indirect determination of medicinal drugs by atomic-absorption spectrometry is reported. The principle of the method is (1) metal chelate formation, and (2) solvent extraction, (3) AAS determination of the metal. The paper describes the determination of L-ascorbic acid by the reduction of the Cu²⁺-neocuproine chelate to the Cu⁺-neocuproine chelate, which is extracted into chloroform in the presence of nitrate.

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Indirekte Bestimmung von Mikromengen Arzneimittel durch Atomabsorptions-Spektrometrie

Zusammenfassung Die indirekte Bestimmung von Arzneimitteln durch AAS wurde beschrieben. Das Prinzip der Methode besteht in der Bildung eines Metallchelates, der Extraktion mit einem Lösungsmittel und der AAS-Bestimmung des Metalls. Beschrieben wurde die Bestimmung der Askorbinsäure durch Reduktion des Kupfer(II)-Neocuproin-Chelates zu der entsprechenden Cu(I)-Verbindung, die in Gegenwart von Nitrat mit Chloroform extrahiert wird.

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Presented at the 8th International Microchemical Symposium, Graz, August 25–30, 1980.     

Determination of humic acid by chemiluminescence

The analytical utility of the chemiluminescence resulting from the reaction of humic acid with permanganate is investigated. The chemiluminescence response curve rises sharply to a peak value at about 0.5 s after mixing and decays somewhat more slowly. The peak signal for a fixed humic acid concentration is shown to pass through a maximum near a permanganate concentration of 17 μmol l^-1 and to increase continuously with potassium hydroxide concentration up to 2.0 mol l^-1. Calibration plots of peak signal vs. humic acid concentration exhibit complex behaviour, being approximately linear up to about 20 mg l^-1, curving slightly toward the concentration axis up to about 40 mg l^-1, and then curving away from the concentration axis above 40 mg l^-1. The detection limit for humic acid is about 0.7 mg l^-1. No interference is observed for thirteen common inorganic species at typical levels in water samples. Substantial differences are observed for humic acid in selected samples determined by the chemiluminescence and visible absorption procedures.     

Determination of small amounts of lead in uranium

Small amounts of lead in the presence of large amounts of uranium can be determined by complexing the lead with nitrilotriacetic acid in aqueous solution at about pH 6 (adjusted with hexamine)and extracting the uranium into a chloroform solution of diphenylacetic acid. The aqueous phase is then acidified the lead determined polarographically.     

化学发光法测定水杨酸

根据在硫酸酸性溶液中高锰酸钾能氧化水杨酸产生化学发光反应 ,而乙二醛的存在可使发光强度增强 ,建立了一种测定水杨酸的化学发光分析法 ,检出限为 8.0× 1 0 -6mol/L,线性范围为 4.0× 1 0 -3～ 6.0× 1 0 -5mol/L。该法巳用于样品复方苯甲酸醇溶液中水杨酸的测定。     

Determination of ultratrace amounts of ruthenium(III) by the delayed autocatalytic reaction using citric acid.

A method for determination of ultratrace amounts (ppq levels) of ruthenium(III) was developed using a copper(II)-phthalocyanine-3,4',4",4"'-tetrasulfonic sodium salt (Cu-PTS) as an indicator in a potassium bromate autocatalytic reaction system. A satisfactory calibration curve of ruthenium(III) ion was obtained by the time measurement in the concentration range of 1 x 10(-13) M to 5 x 10(-12) M with the relative standard deviation (RSD) of 2.8% (n=5). The determination limits (3sigma) were 3.30 x 10(-14) M (3.34 ppq).     

Mechanistic studies on oxidation of L-ascorbic acid by an oxo-bridged diiron complex in aqueous acidic media

[Fe2(micro-O)(phen)4(H2O)2]4+ (1) (Fig. 1, phen = 1,10-phenanthroline) equilibrates with [Fe2(micro-O)(phen)4(H2O)(OH)]3+ (2) and [Fe2(micro-O)(phen)4(OH)2]2+ (3) in aqueous solution in the presence of excess phen, where no phen-releasing equilibria from 1, 2 and 3 exist. 1 quantitatively oxidizes ascorbic acid (H2A) to dehydroascorbic acid (A) in the pH range 3.00-5.50 in the presence of excess phen, which buffers the reaction within 0.05 pH units and ensures complete formation of end iron product ferroin, [Fe(phen)3]2+. The reactive species are 1, 2 and HA- and the reaction proceeds through an initial 1 : 1 inner-sphere adduct formation between 1 and 2 with HA-, followed by a rate limiting outer-sphere one electron one proton (electroprotic) transfer from a second HA- to the ascorbate-unbound iron(III).     

Permanganate-based chemiluminescence analysis of ferulic acid using flow injection.

A simple, sensitive and rapid flow-injection chemiluminescence method has been developed for the determination of ferulic acid based on the chemiluminescence reaction of ferulic acid with potassium permanganate in a nitric acid medium. A strong chemiluminescence signal was observed when ferulic acid was injected into an acidic potassium permanganate solution in a flow-cell. The present method allowed the determination of ferulic acid in the concentration range of 6.0 x 10(-6) to 2.0 x 10(-4) mol l(-1); the detection limit (3sigma) for ferulic acid was 9.6 x 10(-8) mol l(-1). The relative standard deviation was 1.0% for 11 replicate analyses of 2.0 x 10(-4) mol l(-1) ferulic acid. The proposed method was applied to the determination of ferulic acid in real samples with satisfactory results. Moreover, the reaction mechanism of the chemiluminescence system was primarily considered.     

Determination of aminoglycoside antibiotics using an on-chip microfluidic device with chemiluminescence detection

We describe an on-chip microflow injection (μFI) approach for the determination of aminoglycoside antibiotics using chemiluminescence (CL) detection. The method is based on the inhibition of the Cu(II)-catalyzed CL reaction of luminol and hydrogen peroxide by the aminoglycosides due to the formation of a complex between the antibiotic and Cu(II). The main features of the method include small sample volumes and a fast response. Syringe pumps were used to insert the sample and the reagents into the microfluidic device. CL was collected using a fiber optic bundle connected to a luminescence detector. All instrumental, hydrodynamic and chemical variables involved in the system were optimized using neomycin as the aminoglycoside model. Inhibition is proportional to the concentration of the antibiotics. The dynamic ranges of the calibration graphs obtained for neomycin, streptomycin and amikacin are 0.3–3.3, 0.9–13.7, and 0.8–8.5?μmol?L^?1, and the detection limits are 0.09, 0.28 and 0.24?μmol?L^?1, respectively. The precision of the methods, expressed as relative standard deviation, is in the range from 0.8 to 5.0?%. The method was successfully applied to the determination of neomycin in water samples, with recoveries ranging from 80 to 120?%.

化学发光法测定痕量绿原酸

基于绿原酸对鲁米诺-H2O2-辣根过氧化物酶化学发光体系具有强烈的抑制作用,建立了绿原酸的化学发光分析法,并探讨了其作用机理。化学发光强度的变化值与绿原酸浓度的对数在5.2×10-9～1.0×10-6g/mL范围内呈线性关系,检出限(S/N=3)达7.8×10-10g/mL。该方法成功用于金银花中绿原酸含量的测定,回收率为96.0%～100.7%。     

顺序注射化学发光法测定药物中的抗坏血酸

基于在酸性介质中KMnO4氧化抗坏血酸产生化学发光反应,HCHO的存在能使发光强度增强的原理,建立了顺序注射技术与化学发光分析联用测定痕量抗坏血酸的新方法。对进样顺序、体积、流速和浓度各因素进行了优化,在150μL进样体积下,方法的线性范围为1.0×10-9~2.0×10-6mol/L,检出限(3σ)为5.0×10-10mol/L,方法的相对标准偏差为1.3%(1.0×10-7mol/L,n=11)。采样频率为80样/h。应用该法测定维生素C针剂和片剂中的抗坏血酸,结果与标准方法一致。     

NCS-核黄素-盐酸曲普利啶化学发光反应及其分析应用研究

以荧光试剂核黄素为化学发光试剂,构建了N-氯代丁二酰亚胺(NCS)-核黄素-盐酸曲普利啶化学发光新体系。利用此体系建立了测定盐酸曲普利啶的化学发光分析新方法,方法的线性范围为1.0×10-8～9.0×10-7g/mL,检出限为8×10-9g/mL,对浓度为1.0×10-7g/mL盐酸曲普利啶溶液进行11次平行测定的相对...     

KMnO4-乙二醛化学发光体系测定阿魏酸

酸性介质下,KMnO4氧化阿魏酸产生化学发光,乙二醛对该体系有增敏作用。结合流动注射技术,建立了测定阿魏酸的流动注射化学发光新方法。该方法线性范围为1.0×10-7～2.0×10-5mol/L,检出限为1.0×10-8mol/L,对1.0×10-6mol/L的阿魏酸平行测定11次,相对标准偏差为2.8%。该法用于太太美容口服液中阿魏酸的测定,结果令人满意。