Papers by David C Woollard
Journal of AOAC International, Nov 1, 2001
Journal of AOAC International, 2008
Journal of AOAC INTERNATIONAL, 2000
A collaborative study was conducted on a coupled enzymatic–spectrophotometric method for the dete... more A collaborative study was conducted on a coupled enzymatic–spectrophotometric method for the determination of choline in infant formula and milk powders. Twenty-nine laboratories participated in the analysis of 8 blind duplicates over the range of 45–175 mg/100 g sample. After the combined acid hydrolysis–phospholipase release of choline, incubation with choline oxidase in the presence of peroxidase and phenol generates a quinoneimine chromophore with 4-aminoantipyrine. Following raw data screening, overall mean RSDR was estimated at 5.14% (range, 4.26–6.34%) with a HORRAT value of 0.91 (range, 0.76–1.00) and an overall mean RSDr:RSDR value of 0.53 (range, 0.42–0.74). The method was also compared with alternative independent analytical techniques for several of the collaborative study samples.
Journal of AOAC International, Nov 1, 2012
The method was approved by the Expert Review Panel on Strategic Foods Analytical Methods as First... more The method was approved by the Expert Review Panel on Strategic Foods Analytical Methods as First Action. See "Standards News," (2012) Inside Laboratory Management, March/April issue. The AOAC Stakeholder Panel on Strategic Foods Analytical Methods (SPSFAM) invites method users to provide feedback on the First Action methods. Feedback from method users will help verify that the methods are fit for purpose and are critical to gaining global recognition and acceptance of the methods. Comments can be sent directly to the corresponding author.
Acta crystallographica, Feb 1, 1980
Experimental [Th(CI2HloOS)4C14 ], C48H4oCI40484Th, crystallizes in the orthorhombic system, space... more Experimental [Th(CI2HloOS)4C14 ], C48H4oCI40484Th, crystallizes in the orthorhombic system, space group Pbcn, with a = 17-909 (2), b = 13.453 (1), c = 19.636 (2) A, Z = 4. The structure was refined to R =-0.041 for 1877 counter reflexions. The Th atom is eight coordinate with dodecahedal geometry, the CI atoms occupying the dodecahedral B sites and the sulphoxide O atoms the A sites.
Physiologia Plantarum, Nov 1, 1990
To extend our understanding of the physiology of asparagus after harvest, changes in respiration ... more To extend our understanding of the physiology of asparagus after harvest, changes in respiration rate, protein and amino acid complement, and ultrastructure of tip sections (0–30 mm) of asparagus spears (Asparagus officinalis L. cv. Limbras 10) were investigated. Spears had been stored for up to 4 days in the dark at 20°C. Respiration rate (carbon dioxide efflux) declined rapidly after harvest before stabilizing at 12 h at ca 50% of the rate at harvest. Protein, amino acid, and ammonium content of tip sections of 180 mm spears (intact tip sections) during storage, and comparable sections; excised from spears at harvest and subsequently stored (excised tip sections), were compared. Total protein content of intact and excised tip sections increased ca 10% 6–12 h after harvest, and then declined to ca 85% of harvest levels at 48 h. Gel electrophoresis in the presence of sodium dodecyl sulphate revealed the net loss of specific proteins at 48 h. Free amino acid content of excised tip sections declined to ca 75% of harvest levels 12 h after harvest, and then increased to 150% of harvest levels by 48 h. Glutamine levels declined rapidly after harvest, and asparagine content increased ca 200% at 24 h. Similar trends in free amino acid content were found in sections of intact tips. Ammonia (ammonium ions) accumulated to ca 0.3% dry weight at 48 h in both intact and excised tip sections. Ultrastructural studies revealed that tonoplast breakdown commenced 48–96 h after harvest. Results are discussed in relation to the sequence of physiological events following harvest and the timing of mechanisms responsible for their initiation.
Food Analytical Methods, Aug 10, 2019
An automated optical biosensor-based immunoassay exploiting surface plasmon resonance detection f... more An automated optical biosensor-based immunoassay exploiting surface plasmon resonance detection for the quantitation of aflatoxin M 1 (AFM 1) in milk and milk powders is described. A monoclonal antibody and an immobilized protein-AFM 1 conjugate are utilized in a simple inhibition format following aqueous extraction and immunoaffinity clean-up of the sample, thereby avoiding the need for signal amplification techniques. The sensor surface is stable over multiple regeneration cycles, and the technique yields a method detection limit of 0.1 ng g −1 , which is five times lower than the European Commission maximum residue limit. The described antibody-based biosensor technique provides the advantages of quantitative data, automation, and real-time and non-labeled detection of AFM 1. The method therefore facilitates routine quantitative threshold-level screening for the identification of potential non-compliance of AFM 1 content prior to confirmatory analysis by reference chromatographic methods and may be considered to complement the enzyme-linked immunosorbent assay technique.
Inorganic and Nuclear Chemistry Letters, 1978
Food and nutritional components in focus, 2012
Biotin is a member of the B group of water-soluble vitamins. This chapter summarises its chemistr... more Biotin is a member of the B group of water-soluble vitamins. This chapter summarises its chemistry, its biological and nutritional significance in the human diet and its distribution in foods, and describes methods for its quantitative determination in foods, with emphasis on dairy products. The various analytical strategies currently available are briefly reviewed and include microbiological, biological, chromatographic and ligand-binding principles.
Journal of AOAC International, 1997
reports that data has been collected, and a Peer-Verified Method will be reported later in 1996. ... more reports that data has been collected, and a Peer-Verified Method will be reported later in 1996. Phosphorus (Total) in Foods, Colorimetric Method.-Associate Referee Harriet Wallin, VTT Biotechnology and Food Research, Espoo, Finland, reports that the results for the collaborative study were published in/. AOACInt. 77,1557-1561 (1994), and the method was adopted as Method 995.11.
Journal of AOAC International, Nov 1, 2006
Encyclopedia of Food Sciences and Nutrition, 2003
Journal of AOAC INTERNATIONAL, 2000
Biomolecular interaction analysis was evaluated for the automated analysis of biotin- and folate-... more Biomolecular interaction analysis was evaluated for the automated analysis of biotin- and folate-supplemented infant formulas and milk powders. The technique was configured as a biosensor-based, nonlabeled inhibition immunoassay using monoclonal antibodies raised against analyte-conjugate. Sample extraction conditions were optimized and antibodies were evaluated for cross-reactivity. Performance parameters included a quantitation range of 2–70 ng/mL, recoveries of 86–102%, agreement against assigned reference values for National Institute of Standards and Technology Standard Reference Material 1846, between-laboratory reproducibility relative standard deviation of 9.1% for biotin and 8.1% for folate, respectively, and equivalence against reference microbiological assay methods for both analytes.
Journal of AOAC INTERNATIONAL, 2001
The Committee produced several First Action Methods in 1999-2000. Dietary Fiber, Fats, and Oils, ... more The Committee produced several First Action Methods in 1999-2000. Dietary Fiber, Fats, and Oils, and Sugar and Sugar Products were especially active. Work in progress also continued at a high rate. John A.G. Roach of the U.S. Food and Drug Administration (FDA) was appointed as a new Committee member. The Committee voted unanimously on a proposal to reinstate the position of AOAC liaison with the International Commission for Uniform Methods of Sugar Analysis (ICUMSA). ICUMSA, based in Europe, has adopted the joint AOAC-IUPAC protocol for collaborative studies and is a potential source of new validated methods of interest to AOAC INTERNATIONAL. A section of the terms of reference of the Committee was revised (during the conference call meeting in April of 2000) to provide for a one year overlap of experienced members and chair. A conference call meeting of the Committee is planned for January of 2001.
Journal of AOAC INTERNATIONAL, 2002
Vitamin K1 was determined in a variety of foods by using reversed-phase liquid chromatography wit... more Vitamin K1 was determined in a variety of foods by using reversed-phase liquid chromatography with a C30 column followed by post-column reduction to the fluorescent hydroquinone derivatives. Lipids were removed by lipase digestion, followed by single extraction into hydrocarbon, and the protocol was extended to selected natural and processed foods. Biologically active trans- and inactive cis-vitamin K1 isomers were measured individually to evaluate the true nutritional status of the products. Method performance parameters confirmed the validity of the technique. The use of the triacontylbonded C30 phase for selective phylloquinone isomer measurement extends previously validated AOAC Method 999.15 for vitamin K1 in milk and infant formula to a wider range of foods important in the human diet. The cis-vitamin K1 isomer contributes up to about 15% of total phylloquinone in certain foods.
Journal of AOAC International, 2016
Journal of AOAC INTERNATIONAL, 1998
The recommendations were reviewed by the Committee on Food Nutrition. See the report of the commi... more The recommendations were reviewed by the Committee on Food Nutrition. See the report of the committee in this issue. Section numbers refer to Official Methods of Analysis (1995) 16th Ed. and its supplement, Changes in Official Methods of Analysis, 3rd supplement, 1997.
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Papers by David C Woollard