Proficiency reagents used

In their regular day to day practice, field laboratories use commercial reagents or prepare in-house solutions for the calibration of instruments, and they rely on purity assessment of producers. For method validation and even measurement uncertainty, field labs regularly participate in proficiency testing schemes. In such inter-laboratory comparisons, the reference value is usually obtained as the arithmetic mean of results of participants. 

The term quality control (QC) is applied to procedures used to provide evidence of quality and confidence in the analytical results. It includes use of blanks, replication, analysing reference materials or other well-defined samples and participation in Proficiency Testing schemes. Several other features of analysis forming part of QC are control of reagents and instrumentation, equipment maintenance and calibration, and procedures for checking calculations and data transfer. It should be noted that what is referred to as quality assurance in the UK is known as quality control in Japan. 

Prior to running a method, an analyst is often required to demonstrate proficiency in analyzing samples using the method. Many of the USEPA methods require this initial demonshation, and often project QAPs require this for a specific analysis. Sometimes special methods are developed in laboratories for several specific compounds that cannot be determined by routine methods and an IDPF is required. In the IDPF the analyst is required to spike four samples in the appropriate matrix (usually water, soil, or air) and analyze them according to the method. Usually the target analytes are spiked into a clean matrix such as laboratory reagent water or sand to minimize matrix effects. Accuracy is monitored by recoveries of the analyte and precision by the RSD. Often acceptance windows for accuracy and precision are defined in the method or the QAP. These studies... 

While the Turbo-Grignard reagents are proficient at metal-halogen exchange, the amide-based Turbo-Hauser reagents are more useful in selective metal-hydrogen... 

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