Table 9.

Ongoing quality control composition, limits, and frequency.

	Composition		Percent Recovery Limits			Frequency per batch		RPDb limits
Matrix	MB	LCS	CVS	LCS	MS	MSD	Dup	Dup or MSD
Water	reagent water	spiked reagent water	80–120%	80–120%	70–130%	1 of either		≤20%
Soil	wet sand	spiked wet sand	70–130%	50–150%	50–150%	1	1	≤50%
Produce	reagent water	spiked produce	70–130%	60–130%	50–150%	1a	1a	≤50%

^aPer produce type if possible.

^bRPD: Relative Percent Difference.