QA stands for quality assurance and QC for quality control. In Portuguese, the expressions quality assurance and quality control are used, respectively.
QA/QC in environmental analysis is a set of actions undertaken with the aim of promoting the accuracy and precision of analytical data and thus increasing its reliability. While quality assurance is characterized as a broader plan to maintain the quality of the program as a whole, used to identify and correct problems associated with the generation of analytical data, quality control is specific to each activity and consists of the steps that will promote the validity of sampling and technical procedures of analysis.
Quality assurance is implemented through practices such as documenting all technical procedures, conducting training, and documented validation of analytical data.
Data validation includes the review of sampling documents, verification of analytical data, as well as their evaluation by the project scientists and the resolution of problems present in these data. This set of activities aims to correct suspicious or erroneous electronic data and flag those analytical information with potential limitations.
The verification of the quality control of the sampling and the laboratory is carried out through the sampling whites (field, equipment, travel), calibration standards, reference materials (standards), surrogates, LCS, analytical method detection limit studies, etc. In addition, there is also the quality control of the externally evaluated laboratory, such as the interlaboratory analyses.