Approved Method of Recovery Arsenic by Using Reference Materials by FI-HG-AAS
Received Date: Feb 04, 2017 / Accepted Date: Feb 20, 2017 / Published Date: Mar 03, 2017
A flow injection hydride generation atomic (FI-HG-AAS) method was developed for determination of arsenic in certified reference materials after open wet digestion of samples. Steps of the method were optimized and analytical as well as statistical parameters of the method were determined (Detection limit 1 μg/kg-1, Quantification limit 3 μg/kg-1). Accuracy of the method was evaluated using GBW10043 (Rice), GBW100052 (Green tea), T0770 (soya flour), NCS-ZC 73013 (Spinach), NCS-ZC 73015 (Milk powder) reference materials.
Keywords: Arsenic; FI-HG-AAS; Food contaminants; Certified reference materials
The world health organization has recommended a provisional maximum tolerable daily (PMTD) of 2.1 μg/kg body weight per day for inorganic arsenic . Arsenic in most food contains low levels of arsenic, normally below 0.25 mg/kg, exception of some kinds of fish, crustaceans and seaweed . The environmental protection agency recently decreased the maximum permissible concentration of arsenic in drinking water to 0.01 mg/L . Approximately 80% of arsenic compounds are used in pesticides other uses include glassware, paints, and pigments. Arsine gas is used in the semiconductor industry. Arsenic compounds occur in three forms: 1-As5+ pentavalent, organic or arsenate compounds (e.g., alkyl arsenates); 2- As3+ trivalent, inorganic compounds (e.g., sodium arsenate, arsenic trioxide); 3-Arsine gas AsH3 a colorless gas formed by the action of acids on arsenic . Several analytical methods for the quantitative determination of arsenic in biological, environmental and industrial samples have been reported. Estimation of arsenic in most of environmental/biological samples warrants the development of trace analysis methodology with detection limit at ppb. arsenic in the environment is likely to be oxidized to As5+ oxidation state in aerobic condition, so we be converted As5+ to As3+ for the measurement. FI-HG-AAS has been a valuable method to determine Arsenic, Antimony and Selenium in environmental materials. In this article, we device parameters and sample preparation method for the measurement of arsenic express.
Materials and Methods
The most well-known five certified reference materials GBW10043 (Rice), GBW100052 (Green tea), NCS –ZC 73013(spinach), NCS-ZC 73015(Milk powder) China National Analysis Center for Iron and Steel, Beijing, China and T0770 (soya flour) (FAPAS York, UK) were collected which was used to measure arsenic.
Standards and reagents
Analytical reagent–grade chemicals from Chem-lab (Belgium), Merck Millipore and Deionised water with the electrical conductivity of less than 1 μs/cm were used for preparation of all solution and sample dilutions. standards of arsenic (1000 mg/L-1 stock solution Chem-lab) was used for to prepare the working standard (1, 2.5, 5, 10 μg/L-1) in HCl 3% (Merck Millipore) and the use of 5% potassium iodide (Chem-lab) in 5% ascorbic acid (Merck Millipore) for reducing As5+ to As3+. Carrier solution Hcl 3% and 0.3% NaBH4 (Merck Millipore) in 0.05% NaOH reducing agent to produce hydride to used. All volumetric containers and pipettes were soaked in 20% nitric acid (Merck Millipore) overnight and rinsed with Deionised water prior to analysis.
A Perkin Elmer model 4100 atomic absorption spectrophotometer (Germany), equipped with flow injection analysis system (FIAS 200) with an Electro thermal Quartz flow throw cell atomizer was used for the hydride atomization fixed at 900°C. Table 1 shows parameters for determination of arsenic in the samples, using FIAS 200 (Table 1).
|FIAS 200 Recommended Analytical Parameters for Arsenic|
Wavelength: 193.7 nm
Integration Time: 15 sec.
Data Processing Smoothing: 19 points
Cell Temperature: 900°C
Carrier Solution: 3% (v/v) Hcl
Reducing Agent: 0.3% NaBH4 in 0.05% NaOH
Table 1: Parameters for determination of arsenic in the samples, using FIAS 200.
Preparation of sample
For analysis arsenic the content of each certified reference materials with matrix different remove from the refrigerator and the homogenized sample and laid out to reach room temperature. To determine the concentration of arsenic initial mineralization on samples was performed using an open wet digestion. 0.2 gram of a homogenized sample was moved to a Erlenmeyer flask 100 ml and 1 ml Deionized water, 1 ml HNO3 65% (Merck Millipore), 1 ml HClO4 70% (Merck Millipore) and 5 ml H2SO4 98% (Merck Millipore) was added. In order to exit the produced gases and the beginning of oxidation the Erlenmeyer were placed under hood for 20 minutes and then moved on the hotplate with 50-60°C. Digestion to appearance of white vapor continues, and of sample the remaining 1 ml. then the warm solution was left for a 10 minute to reach room temperature and 5 ml of 5% potassium iodide (Chem-lab) in 5% ascorbic acid (Merck Millipore) were added. The solution was diluted to 10 ml with Deionized water. the prepared solution reduce As5+ to As3+ for 1 hours which makes the solution ready for analysis.
Hydride generation system
The HG apparatus is illustrated in Figure 1.
For determination of methods accuracy, recovery tests were performed by certified reference materials samples GBW10043 (Rice), GBW100052 (green tea), NCS–ZC 73013 (spinach), NCS-ZC 73015 (Milk powder) National Analysis Center for Iron and Steel Beijing, China and T0770 (soya flour) (FAPAS, York, UK) which demonstrated good agreement (Table 2), the limit of detection (LOD) and the limit of quantification (LOQ) of the test methods were defined as signal-tonoise ratios of 3 and 10, respectively . LOD and LOQ for the analyzed heavy metals in sample solution were 1.0 and 3.0 μg/kg-1 for arsenic.
|Analyte||GBW10043 (Rice)||GBW100052 (Green tea)||NCS –ZC 73013(spinach)||NCS-ZC 73015 (Milk powder)||T0770 (soya flour)|
|96-132||117 ± 2.1||220-320||267 ± 6.4||200-260||212 ± 2.2||24-38||34 ± 1.8||188-421||303 ± 3.8|
Table 2: Recovery of test of reference of materials.
Discussion and Conclusion
It has been shown that this method can be successfully applied to the determination of arsenic in these types of reference materials. The open Wet Digestion System gave completely digested, clear samples with no loss of arsenic during the given temperature. The Perkin Elmer with FIAS 200 gave good spike recoveries with no matrix interference. Extraction and analysis method described in the article compared with other work done like Rajakovic et al. , Wang et al. , Niedzielski et al. , highly functional and cost-effective in terms of time is.
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Citation: Hasani M, Hadiani MR, Mohammadnia F (2017) Approved Method ofRecovery Arsenic by Using Reference Materials by FI-HG-AAS. J Environ AnalToxicol 7:443. Doi: 10.4172/2161-0525.1000443
Copyright: © 2017 Hasani M, et al. This is an open-access article distributed underthe terms of the Creative Commons Attribution License, which permits unrestricteduse, distribution, and reproduction in any medium, provided the original author andsource are credited.
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