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A highly sensitive fluorescence quenching method for the determination of silicate based on the formation of an ion associate between molybdosilicate and Rhodamine B (RB) in nitric acid medium was developed. A flow injection system coupled with a fluorescence detector was used for the measurement of fluorescence intensity at 560 and 580 nm as excitation and emission wavelengths, respectively. The calibration graph for Si showed a linear range of 0.1–5 ng cm−3 with correlation coefficient of 0.9999, and the detection limit of 0.06 ng cm−3. The proposed method was successfully applied to the determination of silicate in ultrapurified water with satisfactory results. 相似文献
34.
本文叙述一种流动注入吸附溶出一催化极谱测定痕量铂的新技术,它集中了溶出法、催化波和流动注入的优点,达到非常高的灵敏度和分析速度。实验给出了最佳载液组成、流速、注入体积、吸附富集电位和吸附时间等因素。本方法成功地进行了多种铂络合物、矿样和生物样品分析。 相似文献
35.
HAGINAKA Jun 《色谱》2002,20(6):508-518
The author has prepared novel liquid chromatography (LC) packing materials for pharmaceutical and biomedical analysis. Those include LC packing materials for direct serum injection assays of drugs and their metabolites, LC packing materials for resolution of enantiomeric drugs, and uniformly sized molecularly imprinted polymers for drugs and their metabolites. 相似文献
36.
壁喷电池在流动注射阳极溶出伏安法中的应用 总被引:2,自引:0,他引:2
在流动注射阳极溶出伏安法中应用壁喷电池,探讨了非稳定态电积过程的溶出峰电流理论方程,预言了峰电流正比于R~(3/4)(R为工作电极半径),并对有关参数进行了实验验证。对5×10~(-7)mol/L Cd(Ⅱ)连续测定40次,表明相对标准偏差为0.94%。 相似文献
37.
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The thermodynamic model of inorganic arsenic was validated by comparing the predicted As(III) concentration with the experimentally determined one in several river waters samples of the Basque Country (Spain) collected in two sampling campaigns: spring and autumn 2000. This model takes into account the acid-base equilibria of As(III) and As(V) together with the redox equilibria between the H3AsO3 and H3AsO4 species. A correct prediction of As(III) concentration requires the knowledge of the total concentration of arsenic, pH, redox potential (referred to hydrogen electrode), and ionic strength values of the solution. The estimation of the activity coefficients of the arsenic species was performed by means of the Modified Bromley’s Methodology (MBM).In order to perform the experimental As(III) determination, an analytical method was implemented by using an ion exchange separation of As(III)/As(V) on a continuous FIA-IE-HG-AAS system. The total arsenic concentration was determined together with total concentration of the main alkaline or alkaline-earth metals and anions in the natural waters. Temperature compensated measurements of the pH and redox potentials were made in-situ at the sampling sites.For both seasonal campaigns, the agreement between predicted and experimental As(III) is really high for those samples belonging to non polluted river waters. 相似文献
39.
There is a need to develop reliable portable analytical systems for on-site and real-time biomonitoring of lead (Pb) from both occupational and environmental exposures. Saliva is an appealing matrix since it is easily obtainable, and therefore a potential substitute for blood due to existing reasonably good correlation between Pb levels in blood and saliva. The microanalytical system is based on flow-injection/stripping voltammetry with a wall-jet (flow-onto) microelectrochemical cell. Samples that contain as little as 1% saliva can cause electrode fouling, resulting in significantly reduced responsiveness and irreproducible quantitations. In addition, incomplete Pb release from salivary protein can also yield a lower Pb response than expected. This paper evaluates the extent of in vitro Pb-protein binding and the optimal pretreatment for releasing Pb from the saliva samples. Even in 50% by volume of rat saliva, the electrode fouling was not observed, due to the appropriate sample pretreatment and the constant flow of the sample and acidic carrier that prevented passivation by the protein. The system offered a linear response over a low Pb range of 1-10 ppb, low detection limit of 1 ppb, excellent reproducibility, and reliability. It also yielded the same Pb concentrations in unknown samples as did the ICP-MS. These encouraging results suggest that the microanalytical system represents an important analytical advancement for real-time non-invasive biomonitoring of Pb. 相似文献
40.
Paraskevas D. Tzanavaras Demetrius G. Themelis Anastasios Economou Georgios Theodoridis 《Mikrochimica acta》2003,142(1-2):55-62
Two new simple and rapid methods are reported for the accurate and precise spectrophotometric determination of captopril
(CPL) using flow (FI) and sequential injection (SI) analysis. The methods are based on the fast oxidation of CPL by Fe(III).
The produced Fe(II) reacts with 2,2′-dipyridyl-2-pyridylhydrazone (DPPH) in acidic medium to form a colored complex which
is monitored spectrophotometrically at 535 nm. Both methods allow the determination of the analyte up to 1000 mg L−1 at a sampling rate of 120 and 60 injections per hour for FI and SI, respectively. The methods are very precise [s
r=0.8 and 1.2% at 500 mg L−1 CPL (n=12) for FI and SI, respectively] and the 3σ detection limits (c
L=4.0 and 7.0 mg L1, respectively) are quite satisfactory. Their application to a variety of anti-hypertensive commercial pharmaceutical formulations
showed excellent results (relative errors, e
r, < ± 1.6% in all cases compared to an official HPLC method), while common pharmaceutical excipients were found not to interfere.
Recovery experiments further verified the accuracy of the developed methods, as the percent recoveries were in the range of
98.1–102.5%.
Author for correspondence. E-mail: themelis@chem.auth.gr
Received May 9, 2002; accepted January 8, 2003
Published online May 5, 2003 相似文献