Slurry Sampling-Microwave Assisted Leaching Prior to Hydride Generation-Pervaporation-Atomic Fluorescence Detection for the Determination of Extractable Arsenic in Soil

Abstract

A flow injection-pervaporation method, where the sample was introduced as slurry, has been developed for the continuous derivatization and determination of arsenic in soil by hydride generation-atomic fluorescence spectrometry. The removal of arsenic is achieved with the help of a microwave digestor, which facilitates an on-line leaching in the flow injection manifold. Slurries, prepared by mixing the soil (particle size <65 microm) with 6 mol L(-)(1) HCl, were magnetically stirred for 3 min, and while stirring, the pump aspirated the aliquot and filled the loop (500 microL) of the injection valve. An industrial soil and five types of soil (sandy, clayey, slimy, limy, organic) were selected for the optimization of the leaching and determination steps of arsenic, respectively. The results obtained from three certified reference materials [stream sediment GBW 07311 (188 microg/mL As), river sediment CRM 320 (76.7 microg/mL As), and soil GBW 07405 (412 microg/mL As)] using direct calibration against aqueous standards demonstrate the reliability of the method. The relative standard deviation for within-laboratory reproducibility was 4.5%.

Radioanalytical Chemistry for Automated Nuclear Waste Process Monitoring

“…As(III)/As(V); Se(IV)/Se(VI); Cr(III)/Cr(VI); Tc(IV)/Tc(VII)), chemical reactions are typically required to convert the analyte to a desired chemical form or fixed oxidation state prior to total analyte measurements. [1,8,[16][17][18][19][20][21][22][23][24] Sample matrices associated with the aged nuclear waste process streams are comprised of caustic brine solutions where the speciation of 99 Tc is variable and dependent on the source of the waste. [2,25] In some wastes with high organic content, up to 60-70% of total 99 Tc may be present as reduced nonpertechnetate species of unknown chemical composition (to be referred to as "nonpertechnetate").…”

“…Closed-vessel digestion formats are not ideally suited for sample treatment procedures that require sequential addition of multiple reagents or generate significant quantities of gaseous species. [14,28] Although microwave-assisted sample treatment at low temperatures and pressures have been reported in a continuous, flow-through regime using coiled tube flow reactors, which are functionally similar to closed-vessel reactors, [17,21,[29][30][31][32][33] procedures that generate gaseous species result in the formation of gas segments in the tubing. This leads to uncontrolled and irreproducible flow behavior.…”

Tris(4,4′‐dimethyl‐2,2′‐bipyridine)iron(II)‐Exchanged Nafion for Arsenite Determination in Water Samples

“…[5] According to world health organization (WHO) guidelines, the tolerable level of arsenic in potable water is less than 10 mg L À1 . Although numerous analytical methodology/techniques, such as fluorescence, inductively coupled plasma mass spectrometry, atomic absorption spectroscopy, and so forth, have been adopted for the determination of arsenic, [2,[12][13][14][15][16][17] they are not very sensitive (except a few) [18][19][20] and, at the same time, they are time consuming and quite costly. Intake of arsenic can lead to disturbance of cardiovascular and nervoussystem functions, and sharply increases the risk of cancer to skin and other organs of body.…”

Multipumping flow system for improving hydride generation atomic fluorescence spectrometric determinations

“…In order to save reagents and sample, while maintaining high sensitivity, a number of modifications to the way in which the solutions are supplied to the system have been proposed. Besides flow injection [1][2][3] and sequential injection procedures [4,5], the approaches include the use of flow manifolds provided with several solenoid valves for commutation (multicommutated flow injection analysis) [6][7][8][9] or computer-controlled syringes (multisyringe flow injection analysis) [10][11][12].…”