Validation procedures for quantitative gluten ELISA methods: AOAC allergen community guidance and best practices.

The food allergen analytical community is endeavoring to create harmonized guidelines for the validation of food allergen ELISA methodologies to help protect food-sensitive individuals and promote consumer confidence. This document provides additional guidance to existing method validation publications for quantitative food allergen ELISA methods. The gluten-specific criterion provided in this document is divided into sections for information required by the method developer about the assay and information for the implementation of the multilaboratory validation study. Many of these recommendations and guidance are built upon the widely accepted Codex Alimentarius definitions and recommendations for gluten-free foods. The information in this document can be used as the basis of a harmonized validation protocol for any ELISA method for gluten, whether proprietary or nonproprietary, that will be submitted to AOAC andlor regulatory authorities or other bodies for status recognition. Future work is planned for the implementation of this guidance document for the validation of gluten methods and the creation of gluten reference materials.

N-demethylation of cyamemazine via non-classical Polonovski reaction and its conjugation to bovine serum albumin.

A modified Polonovski reaction has been employed to obtain the N-demethylated metabolite of the neuroleptic drug cyamemazine. The synthesis involves N-oxide formation, isolation of the corresponding N-oxide, and a FeSO(4)·7H(2)O mediated Polonovski reaction to afford the desired monodesmethyl cyamemazine. In a subsequent step the hapten N-demethylcyamemazine-hemiglutarate was synthesized and its conjugated to bovine serum albumin (BSA).

Entrapment of functionalized silica microspheres with photo-initiated acrylate-based polymers.

The entrapment of silica-based microspheres, commonly used as stationary phases in chromatography, with an organic porous polymer based on poly(butyl acrylate-co-1,3-butanediol diacrylate) was explored. The spheres were immobilized by photopolymerization leading to entrapped beds within 75 microm i.d. fused silica capillaries, and were mechanically stable, resisting pressure drops of over 5600 psi (38.6 MPa) for only 1 cm of material. The morphology of the polymer formation around the spheres was investigated by SEM and corroborated with back pressure measurements, which indicated that the spheres were held together by encapsulating polymer. The entrapped material was extruded from the capillary in some cases to facilitate imaging. The entrapment conditions were explored, varying the polarity of the sphere surface, the solvent, and the monomers, revealing that polymer formation is based on partitioning of the monomers between the surface and solvent. The resulting polymer morphology is discussed with respect to the effects of confinement, supported by experiments with varying microsphere diameters. The columns described here have favourable properties for use in capillary chromatography and supported catalysis among other applications, and is suitable for lab-on-a-chip devices.

A multi-laboratory evaluation of a clinically-validated incurred quality control material for analysis of allergens in food.

A dessert matrix previously used for diagnosis of food allergies was incurred with pasteurised egg white or skimmed milk powder at 3, 6, 15 and 30 mg allergen protein per kg of dessert matrix and evaluated as a quality control material for allergen analysis in a multi-laboratory trial. Analysis was performed by immunoassay using five kits each for egg and milk (based on casein) and six 'other' milk kits (five based on ß-lactoglobulin and one total milk). All kits detected allergen protein at the 3 mg kg(-1) level. Based on ISO criteria only one egg kit accurately determined egg protein at 3 mg kg(-1) (p=0.62) and one milk (casein) kit accurately determined milk at 6 (p=0.54) and 15 mg kg(-1) (p=0.83), against the target value. The milk "other" kits performed least well of all the kits assessed, giving the least precise analyses. The incurred dessert material had the characteristics required for a quality control material for allergen analysis.