Determination of total arsenic and speciation analysis in Mexican maize tortillas by hydride generation - microwave plasma atomic emission spectrometry and high performance liquid chromatography - inductively coupled plasma - mass spectrometry
The determination of total arsenic (tAs), inorganic As (iAs = As( iii ) + As( v )) and As speciation in Mexican maize tortillas has been undertaken for the first time. Hydride generation - microwave plasma atomic emission spectrometry (HG-MP-AES) with tellurium (sodium tellurite Te( iv )) as the int...
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Published in | Analytical methods Vol. 9; no. 13; pp. 259 - 268 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
07.04.2017
|
Subjects | |
Online Access | Get full text |
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Summary: | The determination of total arsenic (tAs), inorganic As (iAs = As(
iii
) + As(
v
)) and As speciation in Mexican maize tortillas has been undertaken for the first time. Hydride generation - microwave plasma atomic emission spectrometry (HG-MP-AES) with tellurium (sodium tellurite Te(
iv
)) as the internal standard (IS) yielded tAs results in good agreement with those provided by inductively coupled plasma mass spectrometry (ICP-MS). In seven products from local markets, tAs was found in the range of 21.8-192 μg As kg
−1
. Analysis of As(
iii
), As(
v
), MMAs(
v
), and DMAs(
v
) by an established anion exchange liquid chromatography - ICP-MS procedure showed that iAs corresponded to 72.3-98.0% of tAs. A non-chromatographic procedure was envisioned for iAs: diluted tortilla extract or calibration solution (pH 9.0) was loaded on a strong anion exchange cartridge modified with silver chloride, iAs fraction was collected and analyzed by HG-MP-AES with IS. For tAs by HG-MP-AES (with IS) the method quantification limit was 47.6 μg As kg
−1
whereas for iAs it got worse (95 μg As kg
−1
) due to the low recovery of this As form in SPE (<30%). In an attempt to eliminate matrix interference, the lower sample volume was loaded on the cartridge and ICP-MS was used for quantification, yielding an improved percentage recovery of 73.4%. On the other part, the iAs recovery was >93% while analyzing natural water with off-line quantification by any of the two atomic spectrometry techniques, indicating that the chemical matrix of tortillas was responsible for poor SPE performance. It is concluded that HG-MP-AES with IS is a cost-effective alternative for the determination of tAs that offers improved precision under a non-rigorous protocol; however, efficient separation/preconcentration of iAs by SPE is still a challenge.
Determination and speciation of As in tortillas are reported. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 1759-9660 1759-9679 |
DOI: | 10.1039/c7ay00224f |