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( b )  Calibration .—Make single 10 µL injections of calibration solutions fromLinearity 7 through Linearity 1 (omitting Linearity 4a). Calculate the slope, y -intercept, and r 2 value for the calibration curves for Rg 1 , Re, Rb 1 , Rc, Rb 2 , and Rd. The r 2 value should be ≥0.995 for each analyte. Record these values along with peak areas on the appropriate raw data form. Expected retention times for each ginsenoside are listed in Table 2018.09C . (c)  Injection .—Make single 10 µL injections of each test solution. G. Analyzing Raw Data The amount (µg/g) of individual and total ginsenosides for each matrix is to be determined using the seven-point calibration curves. The AOAC INTERNATIONAL Statistical Package ( AOAC INTERNATIONAL Interlaboratory Study Workbook v. 2.0 for Blind Replicates ) is an electronic Excel spreadsheet provided by Tampa Bay Analytical Research (Tampa Bay, FL, USA). The spreadsheet is to be used to statistically analyze the reproducibility and HorRat R value for each sample matrix submitted as blind replicates. For the blind duplicates (whole root, powdered extract, and negative spiked material samples), data should be assessed and outliers removed using Cochran’s test (α = 0.025) and single and double Grubbs’ tests (α = 0.0125). In addition, recovery will be calculated for the negative spiked matrix blank material to verify relative accuracy of each participating laboratory. For samples that are submitted as single replicate samples (capsule and tablet materials), data will be assessed for outliers using the single Grubbs’ test (α = 0.05). Reproducibility is evaluated only by looking at the HorRat r value. H. Calculations Concentration of ginsenoside in the samples is calculated as: Concn, µg/g = [( P o – b o )/ m o ] × ( V / W ) × D where P o = peak area of the ginsenoside in sample chromatogram (mAu*s), b o = y -intercept of the calibration curve for the ginsenoside (mAu*s), m o = slope of the calibration curve for the ginsenoside [mAu*s/(µg/mL)], V = final volume of test solution (mL), W = sample weight (g), and D = dilution factor (final volume/ aliquot volume: 1.2 mL). Average or mean values ( x ):

where X = average or mean value, x i number of individual values. Cochran’s outlier test (C, α = 0.025):

= individual value, and n =

where C j = SD of data series j, N = number of data series that remain in the data set ( N is decreased in steps of 1 upon each iteration of the C test), and S i = SD of data series i (1 < i < N ). Single Grubbs’ test (g, α = 0.05 single replicate, 0.125 blind replicate): = Cochran’s C statistics for data series j, S j

where x i

= suspected outlier (either highest or lowest result),

X = average or mean value, and S = SD. Double Grubbs’ test (G, α = 0.0125):

G = SS

/SS

or G = SS

/SS

n-1,n

o

1.2

o

where SS o = sum of squared deviation from the mean and SS n-1, n or 1.2 = sum of squared deviations obtained after removal of the two highest or the two lowest values, respectively. RSD R among laboratory data: SS

where S = SD among laboratory data and x = average or mean value among laboratory data. Predicted RSD (PRSD): PRSD R = C –0.15 where C = measured analyte concentration in decimal mass units (µg/g, %, ppm, etc.). HorRat R or HorRat r : HorRat R or r = RSD R or R /PRSD R References: J. AOAC Int . 96 , 12(2013) DOI: 10.5740/jaoacint.12-153 (Original publication) J. AOAC Int . (future issue) (First Action) AOAC SMPR 2017.014 J. AOAC Int . 101 , 310(2018) DOI: http://dx.doi.org/10.5740/jaoacint.2017.014 Posted: October 2018

where x i

= individual value and n = number of individual values.

Standard deviation (S):

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