PROFILES MICROTRACE (original) (raw)

Jaoac2019 - Evaluation of the Use of Microtracers

Evaluation of the Use of Microtracers™ in a Proficiency Testing Program, 2019

Background: An effective proficiency testing program must utilize accurate splitting procedures to ensure that customers receive equivalent (by some measure) test items. When test items are not equivalent, it becomes impossible to separate variation among laboratories from variation among test items, and the program cannot achieve its objectives. Therefore, there is a critical need to validate the splitting process used to manufacture test items. Objective: The incorporation of Microtracers TM was investigated for validating the splitting process used in the Association of American Feed Control Officials Proficiency Testing Program and as a potential quality control event for a production run. Methods: Microtracers were incorporated into six production runs. From each run, 12 test items were randomly selected for evaluation. Proficiency test materials were prepared from commercially available feedstuffs using base animal feeds and feed additives. The tracers were incorporated into base feed with other additives, recovered, and counted from the randomly selected test items. Results: Uniformity of test items was evaluated with the following two statistical methods: (1) relative standard deviation (RSD) of particle counts according to a Poisson distribution and (2) a Pearson's Chi-square test. RSDs for counts (per mass basis) ranged from 2.49 to 4.13%, and Chi-square P values ranged from 0.0097 to 0.3740 over the six sets. Conclusions: Microtracers were determined to be a potential tool for validating the splitting process used to manufacture

Bioapplications of solid phase microextraction

2001

Solid phase microextraction ( S m ) has experienced rapid development in the recent decade. Especi aU y for volatile org anic compounds in environment al sample anaiysis, SPME features the special advantages of cornbining sampling, sample preparation, and sample transfer into a single step. However, due to the complexity of biomatrices and non-volatile and polar nature of the dmg compounds, most dmg analyses by SPME and in-tube SPME are still in their primary analytical optimization stage. Based on the fact that SPME is an equilibrium extraction process, in this thesis, SPME has been successfûlly applied for dmg-protein studies. The theory of protein binding study by headspace SPME was fmt illustrated with selected alkylbenzene compounds binding to bovine serum albumin (BSA) as the model system. Drug binding to human serum albumin (HSA) was subsequentl y studied by direct SPME due to the non-volatile and polar nature of the model h g , diazepam. This method can be easily adapted to ...