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Uncertainties of gas chromatographic measurement of troublesome pesticide residues in apples employing conventional and mass spectrometric detectors [An article from: Analytica Chimica Acta]
Book Details
PublisherElsevier
ISBN / ASINB000RR03EO
ISBN-13978B000RR03E9
MarketplaceUnited Kingdom 🇬🇧
Description
This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2004. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
In recent years the declaration of estimated uncertainty of measurement has become an integral part of analytical results. This study presents the assessment of results generated within the analysis of selected pesticides represented by carbamates, pyrethroides and azoles, residues of which may be found in treated apples. Multiresidue method used for analysis of spiked samples (residues at levels 0.040-0.163mg/kg) consisted of (i) ethyl acetate extraction, (ii) GPC clean-up and (iii) identification/quantification of residues by GC. Procedures utilizing either conventional (electron-capture, nitrogen-phosphorus) or mass-selective detectors (quadrupole and ion trap analyzer) were evaluated. The results generated through alternative strategies of uncertainty estimation ('bottom-up', 'top-down') were compared. Using the 'bottom-up' approach uncertainty of extraction which comprises two components-(i) repeatability of extraction and (ii) uncertainty of extraction recovery was shown to represent the main source of combined standard uncertainty (values of uncertainty of extraction for tested pesticides ranged from 4.6% to 21.6%). On the other hand, uncertainties associated with the GC calibration (uncertainties of weighing and diluting standards, uncertainties of purity of standards) were not so important (most of them did not exceed 2%). Combined standard uncertainties associated with the described analytical method ranged for individual compounds from 9.3% to 24.3%. Similar values of combined standard uncertainties were obtained using the alternative 'top-down' approach.
Description:
In recent years the declaration of estimated uncertainty of measurement has become an integral part of analytical results. This study presents the assessment of results generated within the analysis of selected pesticides represented by carbamates, pyrethroides and azoles, residues of which may be found in treated apples. Multiresidue method used for analysis of spiked samples (residues at levels 0.040-0.163mg/kg) consisted of (i) ethyl acetate extraction, (ii) GPC clean-up and (iii) identification/quantification of residues by GC. Procedures utilizing either conventional (electron-capture, nitrogen-phosphorus) or mass-selective detectors (quadrupole and ion trap analyzer) were evaluated. The results generated through alternative strategies of uncertainty estimation ('bottom-up', 'top-down') were compared. Using the 'bottom-up' approach uncertainty of extraction which comprises two components-(i) repeatability of extraction and (ii) uncertainty of extraction recovery was shown to represent the main source of combined standard uncertainty (values of uncertainty of extraction for tested pesticides ranged from 4.6% to 21.6%). On the other hand, uncertainties associated with the GC calibration (uncertainties of weighing and diluting standards, uncertainties of purity of standards) were not so important (most of them did not exceed 2%). Combined standard uncertainties associated with the described analytical method ranged for individual compounds from 9.3% to 24.3%. Similar values of combined standard uncertainties were obtained using the alternative 'top-down' approach.
