Quality control, reagents

Quality control reagents Use 19F NMR spectroscopy or react each resin with 2-methylbenzylamine followed by 1H NMR analysis... 

The other analytical methods necessary to control the typical specification given in Table 5 are, for the most part, common quality-control procedures. When a chemical analysis for purity is desired, acetylation or phthalation procedures are commonly employed. In these cases, the alcohol reacts with a measured volume of either acetic or phthalic anhydride in pyridine solution. The loss in titratable acidity in the anhydride solution is a direct measure of the hydroxyl groups reacting in the sample. These procedures are generally free from interference by other functional groups, but both are affected adversely by the presence of excessive water, as this depletes the anhydride reagent strength to a level below that necessary to ensure complete reaction with the alcohol. Both procedures can be adapted to a semimicro- or even microscale deterrnination. 

Even inside the controlled conditions of a research laboratory, analyzing clean and standardized test samples PCR procedures requires careful quality control, taking into consideration differences in sample preparation, variation in pipetting, differences in reaction tube thickness, poor calibration or instability of the thermal cycler, and reagent quality. 

Other considerations could include availability of reagent(s) or equipment, method for routine analyses vs limited samples, and confirmatory method vs multi-residues. Plan for method validation and/or analytical quality control. 

Check reagents, standards and reference materials to ensure that adequate stocks of the correct grades are available. Where reagents and quality control samples require preparation, this may need to be done in advance. If stocks of prepared reagents already exist, these must be checked to ensure that they are still usable. All reagents should be well-labelled. 

Single-site IVD "Home brew" or "in-house" IVD made with an analyte specific reagent FDA requires labeling disclosing the "in-house" nature of the test but has no premarket review requirement CLIA requires analytical validation and quality control systems... 

In systematic sampling, a sample is taken at set intervals (such as every fifth container of reagent or taking a sample of water from a fixed sample point in a flowing stream every hour). This is most commonly employed in quality assurance or (in the clinical chemistry lab) in quality control. 

The above list of potential advantages of automated immunostainers summarizes their strengths. Automation cannot, however, correct faulty cell or tissue preparahve techniques, which would lead to the failure of any immunostaining method. Automated staining also cannot correct for the improper selection of tissue to be examined, or for selection of antisera and associated reagents that produce nonoptimal or inconclusive results. Automation is no panacea for laboratories that have poor quality control procedures, since good laboratory practices are required to operate automated Stainers successfully. 

Reagents should have reasonable shelf life with no availability problems. Quality control of reagent lots must be available if questions of sensitivity or specificity should arise. 

The Ventana 320 is designed to be used only with detection reagents, enzymes, chromogens, and counterstains supplied by Ventana, but it allows the use of primary antisera not marketed by the company. To use such antisera, however, the company requires purchase of Ventana pipeters and bar codes for each individual antisera. Although this limits a laboratory s ability to be flexible, it assists in assuring quality control of reagents. 

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