Development and Application of Top-Down Approaches for Estimating Measurement Uncertainty of GMO Quantitative Results
[Objective]The enforcement of labeling regulations on genetically modified organisms(GMOs)requires establishing a standard system for accurate quantification of GMOs that includes the standard or guide for estimating measurement uncertainty(MU).It is urgent to establish a standardized top-down approach for estimating MU of quantitative results,which is conveniently adopted by the general testing laboratories.[Method]There are two approaches for estimating the MU introduced by precision of quantitative method,one is to establish the equation of MU estimation using data obtained on 15 routine samples based on the"uncertainty function",the other is to evaluate the MU by repeatedly measuring a certified reference material(CRM)and calculating the intermediate precision.The uncertainty introduced by bias is evaluated using a CRM or a sample prepared by laboratory as bias control.The uncertainty of the nominal value of the sample prepared by laboratory is evaluated by using a simplified program based on the preparation process.The MU contributed by method precision and bias are combined into the standard uncertainty of the quantitative results,and then multiplied by the coverage factor k to obtain the expanded uncertainty.[Result]The event-specific PCR method of genetically modified maize DBN9936 was took as an example.The MU of method precision was evaluated to be 0.76%using simulated DBN9936 routine samples,and to be 0.33%using a CRM(GBW(E)100901).Compared with routine samples,the MU of method precision evaluated using a CRM is significantly underestimated.The uncertainty introduced by bias was evaluated to be 0.26%using a CRM(GBW(E)100901)as a bias control.Using a laboratory prepared powder sample and a genomic DNA sample(nominal values of 3.0%)as bias control,the bias uncertainty was evaluated to be 0.20%and 0.19%,respectively.Since the simplified program ignored some uncertainty components,the uncertainty of the nominal value of laboratory prepared samples was estimated to be smaller.By combining the MU of method precision and bias,the expanded uncertainty using routine samples was obtained to be 1.26%,1.20%,and 1.20%,respectively,the expanded uncertainty using a CRM was 0.84%,0.78%,and 0.76%,respectively.[Conclusion]This study established the top-down approaches for MU estimation of quantitative results,testing laboratories should prioritize routine samples to estimate the MU contributed by the method precision,and select CRMs as bias control in principle to evaluate bias uncertainty during GMO quantification.
quantitative results of GMO contentmeasurement uncertaintytop-down approachcertified reference materialsbias control
国家科技期刊平台
NSTL
万方数据
维普
