University of North Florida
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Contact Info

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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LGC 6010

Classification: Reference Material -> LGC -> 6010 -> Hard drinking water

Citations 4

"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

"Preconcentration And Determination Of Inorganic Arsenic Using A Multisyringe Flow Injection System And Hydride Generation-atomic Fluorescence Spectrometry"
Talanta 2004 Volume 64, Issue 5 Pages 1335-1342
L. O. Leal, N. V. Semenova, R. Forteza and V. Cerdà

Abstract: A new multisyringe flow injection system for inorganic arsenic determination at trace levels by hydride generation-atomic fluorescence spectrometry (HGAFS) is presented. Preconcentration on a solid-phase was carried out using a column packed with an anion-exchange resin (Amberlite IRA-410). The reagents are dispensed to the system using a multisyringe burette coupled with two multi-port selection valves. Different parameters were changing in order to make the system as effective as possible. An analytical curve was obtained for arsenic determination between 50 and 2000 ng l-1. This new approach improved five times the sensitivity over a MSFIA-HGAFS technique developed previously by the authors. Detection limit of the proposed technique was (3sb/S) of 30 ng l-1. The relative standard deviation (RSD) of As at 1 µg L-1 was 4.8% (n=7). A sample throughput of 10 h-1 has been achieved. The proposed method has been applied to different reference solid and water materials with satisfactory results.
Arsenic, inorganic Fluorescence Preconcentration Solid phase extraction Amberlite Multisyringe Sensitivity Optimization

"Antimony Determination And Speciation By Multisyringe Flow Injection Analysis With Hydride Generation-atomic Fluorescence Detection"
Anal. Chim. Acta 2005 Volume 530, Issue 1 Pages 113-120
N.V. Semenova, L.O. Leal, R. Forteza and V. Cerdà

Abstract: A new analytical procedure for determination of inorganic antimony and speciation of antimony(III) and antimony(V) is presented. For this purpose, a software-controlled time-based multisyringe flow injection system, which contains a multisyringe burette provided with a multi-port selection valve, was developed. Hydride generation-atomic fluorescence spectrometry was used as a detection technique. A 0.3% (w/v) reducing sodium tetrahydroborate solution, hydrochloric acid (2 M), an antimony solution and a pre-reducing solution of 10% (w/v) KI and 0.3% (w/v) ascorbic acid are dispensed simultaneously into a gas-liquid separation cell with further propulsion of the reaction product into the flame of an atomic fluorescence spectrometer using argon flow. A hydrogen flow was employed to support the flame. The linear range and the detection limit (3sb/S) of the proposed technique were 0.2-5.6 µg L-;1 and 0.08 µg L-;1, respectively. A sample throughput of 18 samples per hour (corresponding to 80 injections per hour) was achieved. The relative standard deviation for 18 independent measurements was 4.6%. This technique was validated by means of reference solid and water materials with good agreement with the certified values. Satisfactory results for speciation of Sb(III) and Sb(V) by means of the developed technique were obtained.
Antimony(3+) Antimony(5+) Fluorescence Multisyringe Speciation Automation Optimization Interferences Method comparison

"Optical Fibre Reflectance Sensor For The Determination And Speciation Analysis Of Iron In Fresh And Seawater Samples Coupled To A Multisyringe Flow Injection System"
Anal. Chim. Acta 2005 Volume 528, Issue 2 Pages 197-203
Carmen Pons, Rafael Forteza and Víctor Cerdà

Abstract: A novel optical fiber reflectance sensor coupled to a multisyringe flow injection system (MSFIA) for the determination and speciation analysis of iron at trace level using chelating disks (iminodiacetic groups) is proposed. Once iron(III) has been retained onto a chelating disk, an ammonium thiocyanate stream is injected in order to form the iron(III)-thiocyanate complex which is spectrophotometrically detected at 480 nm. Iron(III) is eluted with 2 M hydrochloric acid so that the chelating disk is regenerated for subsequent experiments. The determination of total iron is achieved by the on-line oxidation of iron(II) to iron(III) with a suitable hydrogen peroxide stream. A mass calibration was feasible in the range from 0.001 to 0.25 µg. The detection limit (3sb/S) was 0.001 µg. The repeatability (RSD), calculated from nine replicates using 1 mL injections of a 0.1 mg/l concentration, was 2.2%. The repeatability between five chelating disks was 3.6%. The applicability of the proposed methodology in fresh and seawater samples has been proved. The proposed technique has been validated by replicate analysis (n = 4) of certified reference materials of water with satisfactory results.
Iron(2+) Iron(III) Spectrophotometry Sensor Reference material Speciation Chelation Optical fiber