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Q

QA
quality assurance
QAPP
quality assurance project plan
QC
quality control
qualifier
See (data validation) qualifier
qualitative analysis
identification of components of a sample, or testing for the presence of a component (cf. quantitative analysis)
quality assurance (QA)
“an integrated system of management activities involving planning, implementation, documentation, assessment, reporting, and quality improvement to ensure that a process, item, or service is of the type and quality needed and expected by the customer.” [EPA 2000]
quality assurance officer
employee of an organization with primary responsibility for oversight of the organization’s quality system — also called quality assurance manager
quality assurance project plan (QAPP)
“a document describing in comprehensive detail the necessary quality assurance, quality control, and other technical activities that should be implemented to ensure that the results of the work performed will satisfy the stated performance criteria.” [EPA 2000]
quality control (QC)
“the overall system of technical activities that measures the attributes and performance of a process, item, or service against defined standards to verify that they meet the stated requirements established by the customer; operational techniques and activities that are used to fulfill requirements for quality.” [EPA 2000]
quality control sample (QC sample)
sample, either real or artificially prepared, analyzed routinely with other normal samples, which is used primarily to assess the measurement process and not merely to determine the value of the measurand — e.g., method blank, laboratory duplicate, laboratory control sample, matrix spike
quality manual
official document or collection of such documents that describe a laboratory’s quality system
quality system
“a structured and documented system describing the policies, objectives, principles, organizational authority, responsibilities, accountability, and implementation plan of an organization or ensuring quality in its work processes, products (items), and services. The quality system provides the framework for planning, implementing, documenting, and assessing work performed by the organization and for carrying out required quality assurance and quality control.” [EPA 2000]
quantify
1. to measure the value of (a particular quantity) with good relative precision
2. to measure the value of (a particular quantity)
quantification capability
ability of a measurement process to quantify the measurand, typically described in terms of the minimum quantifiable value
quantification limit
minimum quantifiable value
quantile
If X is a random variable and p is a real number between 0 and 1, then a p-quantile of X is any number xp such that Pr(X < xp) ≤ p and Pr(Xxp) ≥ p (see also percentile).
quantitative analysis
quantification of components of a sample (cf. qualitative analysis)
quantity
See (measurable) quantity
quench curve
plot of detection efficiency versus a quench indicator
quench; quenching
in liquid scintillation counting, any process that decreases the amount of light energy produced by the scintillator and detected by the photomultiplier tube
quench indicating parameter (QIP); quench indicator
in liquid scintillation counting, a quantity that is measured for each source and used to estimate the degree of quenching for that source