Define QA
Quality assurance is a system of monitoring, evaluating and documenting that leads proof of analysis
Sample QA responsibilities
- reporting in timely manner
- reporting results to the appropriate individual
- make sure lab if functioning efficiently
- continuing ed programs for lab workers
- evaluating lab personnel. Identify areas of improvement
- use reliable tests
- verify final reports
Define qc
Quality control describes the day to day monitoring of the accuracy and precision at lab level
Sample qc responsibilities
- standard operating procedures (sops)
- blanks, duplicates and control samples
- calibration stds
- matrix spikes
- control charts
Define sops
Standard operating procedures
Define Qassess
Quality assessment is a Challenge to the effectiveness of a QA and QC programs . Measure of the quality assurance and quality control practices that are in place
Sample Qassess activities
- blinds, round robins
- performance evaluation samples
- certified reference materials
- audits
What blanks used in the field
- equipment (rinsate) blanks
- field blanks
- trip blanks
Explain rinsate blanks
Checks contamination of sampling equipment
Explain field blanks
Checks contamination from the sampling equipment
Explain trip blanks
Checks contamination from artifacts introduced by cross contamination
2 types of background samples
- control samples
2. Spike samples
Explain control samples
Samples taken from control site must be collected (upwind of suspect site and up gradient with ground water)
Explain spike samples
A known amount of analyte is added to the sample during collection. Identify any transport, field, matrix effects or interferences that may be present . (Useful if background samples aren’t available)
Define accuracy
Accuracy is a measure of closeness to true value
Define precision
Describes the overall uncertainty from
A random variation. It is a measure of the repeatability of an analysis
Define bias
Bias is a directional error, expressed as either high or low. Bias refers to variation of data from theoretical value
Define error
- systematic (determinant)
- >systematic error are reproducible inaccuracies that are consistently in the same direction. This type of error effects the data average - random (indeterminate)
- > random errors are statistical fluctuations (in either direction) in the measure data . They add variability to the data but do not affect average
3 sources of error
- data phase
- implementation
- Lab analysis
Quality control practices used to minimize errors
- control samples (spikes and blanks)
- documentation (record keeping and indelible ink)
- training
- equipment maintenance (preventative maintenance)
- equipment calibration
Sam
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