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Figure 5 | Environmental Health

Figure 5

From: A round robin approach to the analysis of bisphenol a (BPA) in human blood samples

Figure 5

Comparison of indirect and direct methods. Three laboratories analyzed the phase 3 samples for total BPA (uBPA + BPA-G) using both direct and indirect methods. For the indirect methods, enzyme was used at the concentrations and duration of treatment indicated (see also Table 4). The indirect method used by Laboratory 2 replicates the protocol used by the CDC and the indirect method used by Laboratory 3 replicates the protocol used by NCTR/FDA. All three laboratories had verified methods for the analysis of Phase 3 samples, with at least 4 of 5 spiked samples concentrations reported within 20% of the actual spiked amount (indicated by the number over the suite of 5 samples). None of the indirect methods were verified using these criteria. The yellow bar shows 20% accuracy around the actual spiked amount.

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