One concern in any analysis is the impact of the sample’s matrix. A method for an analyte that is known to work well in one matrix may yield problems when applied to a sample with a different matrix. One way to evaluate for a matrix effect is to run what is called a spike recovery. Basically, the sample is analyzed and the analyte’s concentration determined. A known amount of analyte is then added (the spike), the analysis is repeated, and the concentration of added analyte determined. Ideally, the amount recovered should equal the amount added. Lang and Wai [Anal. Chem. 1999, 71, 2929-2933] recently developed a method for determining ginkgolides and bilobalides in ginkgo leaves. In one part of their study they spiked samples with 50.0 μg of a ginkgolide and obtained recoveries (in μg) of
46.8 50.6 47.6 46.4 48.8
Is there any evidence at α = 0.05 that the matrix is affecting the recovery?