Optimization of analytical quality control for long-term monitoring of metals and volatile organic compounds in groundwater

Statistical analysis of historical results for matrix spikes (MS), matrix spike duplicates (MSD), and laboratory control samples (LCS) from aqueous samples analyzed for metals and volatile organic compounds was performed to determine whether the MS/MSD provided substantive information apart from that provided by the LCS. The statistical analysis showed that the mean recovery of all analytes from MS/MSD closely approximated the mean recovery of all analytes from the LCS. Average bias, skewness, and kurtosis were also assessed for both data sets. The evaluation provided strong evidence for the use of LCS recoveries as performance indicators of probable MS/MSD recoveries of metals and volatile organic compounds from groundwater.