University of North Florida
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Stuart Chalk, Ph.D.
Department of Chemistry
University of North Florida
Phone: 1-904-620-1938
Fax: 1-904-620-3535
Email: schalk@unf.edu
Website: @unf

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BCR 279

Classification: Reference Material -> BCR -> 279 -> Sea lettuce

Citations 2

"Multisyringe Flow Injection System For Total Inorganic Selenium Determination By Hydride Generation-atomic Fluorescence Spectrometry"
Anal. Chim. Acta 2003 Volume 486, Issue 2 Pages 217-225
N. V. Semenova, L. O. Leal, R. Forteza and V. Cerdà

Abstract: A new multisyringe flow injection system for total inorganic selenium determination by hydride generation-atomic fluorescence spectrometry (HGAFS) has been proposed. The flow methodology is based on the simultaneous injection of sample in the acid media (50% HCl), a reducing sodium tetrahydroborate solution (0.18%) and a solution of hydrochloric acid (50%) which are dispensed into a gas-liquid separation cell by using a multisyringe burette coupled with one multiport selection valve. The usage of the time-based injection increases the sample throughput and provides precise known volumes of sample. The hydride of selenium is delivered into the flame of an atomic fluorescence spectrometer by means of an argon flow. A hydrogen flow has been used to support the flame.The technique can be applied over a wide range of concentrations of selenium between 0.1 and 3.5 µg L-1 with good repeatability (relative standard deviation (RSD) values 4.6-7% for 1 µg L-1 of Se). The detection limit of the developed technique (3sb/S) was 0.01 µg L-1. A sample throughput was 28 samples per hour (84 injections). The multisyringe technique has been validated by means of reference solid (sea lettuce) and water (hard drinking water) materials with good agreement with certified values. The analytical features were compared with those obtained by using of the commercial flow injection analysis (FIA) system. The proposed method provides a higher sampling frequency and a significant reduction of reagent and sample consumption in front the flow injection application.
Selenium, inorganic Fluorescence Multisyringe Automation Interferences Optimization Method comparison Reagent consumption Phase separator

"Speciation Analysis Of Inorganic Arsenic By A Multisyringe Flow Injection System With Hydride Generation–atomic Fluorescence Spectrometric Detection"
Talanta 2006 Volume 69, Issue 2 Pages 500-508
L.O. Leal, R. Forteza and V. Cerdà

Abstract: In this study, a new technique by hydride generation-atomic fluorescence spectrometry (HG-AFS) for determination and speciation of inorganic arsenic using multisyringe flow injection analysis (MSFIA) is reported. The hydride (arsine) was generated by injecting precise known volumes of sample, a reducing sodium tetrahydroborate solution (0.2%), hydrochloric acid (6 M) and a pre-reducing solution (potassium iodide 10% and ascorbic acid 0.2%) to the system using a multisyringe burette coupled with one multi-port selection valve. This solution is used to pre-reduce As(V) to As(III), when the task is to speciate As(III) and As(V). As(V) is determined by the difference between total inorganic arsenic and As(III). The reagents are dispensed into a gas-liquid separation cell. An argon flow delivers the arsine into the flame of an atomic fluorescence spectrometer. A hydrogen flow has been used to support the flame. Nitrogen has been employed as a drier gas (Fig. 1). Several variables such as sample and reagents volumes, flow rates and reagent concentrations were investigated in detail. A linear calibration graph was obtained for arsenic determination between 0.1 and 3 µg l-;1. The detection limit of the proposed technique (3sb/S) was 0.05 µg l-;1. The relative standard deviation (RSD) of As at 1 µg l-;1 was 4.4 % (n = 15). A sample throughput of 10 samples per hour was achieved. This technique was validated by means of reference solid and water materials with good agreement with the certified values. Satisfactory results for speciation of As(III) and As(V) by means of the developed technique were obtained.
Arsenic(3+) Arsenic(5+) Fluorescence Speciation Volatile generation Multisyringe Interferences