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Two-dimensional heart-cut LC-LC improves accuracy of exact-matching double isotope dilution mass spectrometry measurements of aflatoxin B1 in cereal-based baby food, maize, and maize-based feed.

Breidbach A, Ulberth F - Anal Bioanal Chem (2015)

Bottom Line: This is evidenced by the expanded measurement uncertainty (k=2) of 0.017 μg/kg or 8.9 % relative to a mass fraction of aflatoxin B1 in a cereal-based baby food of 0.197 μg/kg.This value is in perfect agreement with the consensus value of this material from a proficiency test (PT) scheme for National Reference Laboratories executed by the European Reference Laboratory for Mycotoxins.The effort necessary to perform the described methodology precludes its frequent use but for specific applications we see it as a valuable tool.

View Article: PubMed Central - PubMed

Affiliation: European Commission, Joint Research Center, Institute for Reference Materials and Measurements, 2440 Geel, Belgium. andreas.breidbach@ec.europa.eu

ABSTRACT
Aflatoxins, mycotoxins of fungi of the Aspergillus sp., pose a risk to consumer health and are, therefore, regulated by more than 100 countries. To facilitate method development and validation as well as assessment of measurement capabilities, availability of certified reference materials and proficiency testing schemes is important. For these purposes, highly accurate determinations of the aflatoxin content in the materials used are necessary. We describe here the use of two-dimensional heart-cut LC-LC in combination with exact-matching double isotope dilution mass spectrometry to determine the content of aflatoxin B1 in three materials used in a proficiency testing scheme. The serious reduction in ionization suppression afforded by the two-dimensional heart-cut LC-LC had a positive effect on the precision of the measured isotope ratios of the exact-matching double isotope dilution mass spectrometry. This is evidenced by the expanded measurement uncertainty (k=2) of 0.017 μg/kg or 8.9 % relative to a mass fraction of aflatoxin B1 in a cereal-based baby food of 0.197 μg/kg. This value is in perfect agreement with the consensus value of this material from a proficiency test (PT) scheme for National Reference Laboratories executed by the European Reference Laboratory for Mycotoxins. The effort necessary to perform the described methodology precludes its frequent use but for specific applications we see it as a valuable tool.

No MeSH data available.


Related in: MedlinePlus

Box and Whisker plot of isotope ratio of analyte ion peak area over spike ion peak area for the feed material spiked volumetrically after extraction
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Related In: Results  -  Collection


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Fig1: Box and Whisker plot of isotope ratio of analyte ion peak area over spike ion peak area for the feed material spiked volumetrically after extraction

Mentions: Based on previous experience and published data [29], ACN/water (80/20, v/v) was chosen as extraction solvent since its extraction yield in cereals is sufficiently high. As fast cycle time was considered to be important, isocratic separation with a very efficient fused-core C18 column was initially selected and MS settings were optimized with a series of designed experiments. With this set-up, injection volumes of crude extract in excess of 5 μL led to peak distortion. It also became apparent that AFB1 suffered from significant suppression in the ion source. This is in agreement with what has been reported for aflatoxins in maize [19] and even the use of an analytical column with sub-2 μm particles was unable to alleviate this [9]. While this suppression did not affect the magnitude of the observed isotope ratio (the benefit of IDMS), it did have an impact on the repeatability of the measurements (Fig. 1).Fig. 1


Two-dimensional heart-cut LC-LC improves accuracy of exact-matching double isotope dilution mass spectrometry measurements of aflatoxin B1 in cereal-based baby food, maize, and maize-based feed.

Breidbach A, Ulberth F - Anal Bioanal Chem (2015)

Box and Whisker plot of isotope ratio of analyte ion peak area over spike ion peak area for the feed material spiked volumetrically after extraction
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4383822&req=5

Fig1: Box and Whisker plot of isotope ratio of analyte ion peak area over spike ion peak area for the feed material spiked volumetrically after extraction
Mentions: Based on previous experience and published data [29], ACN/water (80/20, v/v) was chosen as extraction solvent since its extraction yield in cereals is sufficiently high. As fast cycle time was considered to be important, isocratic separation with a very efficient fused-core C18 column was initially selected and MS settings were optimized with a series of designed experiments. With this set-up, injection volumes of crude extract in excess of 5 μL led to peak distortion. It also became apparent that AFB1 suffered from significant suppression in the ion source. This is in agreement with what has been reported for aflatoxins in maize [19] and even the use of an analytical column with sub-2 μm particles was unable to alleviate this [9]. While this suppression did not affect the magnitude of the observed isotope ratio (the benefit of IDMS), it did have an impact on the repeatability of the measurements (Fig. 1).Fig. 1

Bottom Line: This is evidenced by the expanded measurement uncertainty (k=2) of 0.017 μg/kg or 8.9 % relative to a mass fraction of aflatoxin B1 in a cereal-based baby food of 0.197 μg/kg.This value is in perfect agreement with the consensus value of this material from a proficiency test (PT) scheme for National Reference Laboratories executed by the European Reference Laboratory for Mycotoxins.The effort necessary to perform the described methodology precludes its frequent use but for specific applications we see it as a valuable tool.

View Article: PubMed Central - PubMed

Affiliation: European Commission, Joint Research Center, Institute for Reference Materials and Measurements, 2440 Geel, Belgium. andreas.breidbach@ec.europa.eu

ABSTRACT
Aflatoxins, mycotoxins of fungi of the Aspergillus sp., pose a risk to consumer health and are, therefore, regulated by more than 100 countries. To facilitate method development and validation as well as assessment of measurement capabilities, availability of certified reference materials and proficiency testing schemes is important. For these purposes, highly accurate determinations of the aflatoxin content in the materials used are necessary. We describe here the use of two-dimensional heart-cut LC-LC in combination with exact-matching double isotope dilution mass spectrometry to determine the content of aflatoxin B1 in three materials used in a proficiency testing scheme. The serious reduction in ionization suppression afforded by the two-dimensional heart-cut LC-LC had a positive effect on the precision of the measured isotope ratios of the exact-matching double isotope dilution mass spectrometry. This is evidenced by the expanded measurement uncertainty (k=2) of 0.017 μg/kg or 8.9 % relative to a mass fraction of aflatoxin B1 in a cereal-based baby food of 0.197 μg/kg. This value is in perfect agreement with the consensus value of this material from a proficiency test (PT) scheme for National Reference Laboratories executed by the European Reference Laboratory for Mycotoxins. The effort necessary to perform the described methodology precludes its frequent use but for specific applications we see it as a valuable tool.

No MeSH data available.


Related in: MedlinePlus