5. AOACSPDSMethods-2018AwardsV3

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4 K line et al .: J ournal of AOAC I nternational V ol . 100, N o . 3, 2017

Figure 2016.09A. HPLC chromatogram of an 80 ppb standard mixture injection. A refers to aloins A and B at 380 nm.

Figure 2016.09B. HPLC chromatogram of an 80 ppb standard mixture injection. B refers to aloe-emodin at 430 nm.

Results and Discussion

I. Calculations

Obtain the standard curves for aloins A and B (and aloe- emodin, if necessary) by plotting the standard concentrations of aloins A and B (and aloe-emodin, if necessary) versus the peak areas of aloins A and B (and aloe-emodin, if necessary). Calculate the amount of aloin A and B (and aloe-emodin, if necessary) in the sample according to the formulas below for the raw materials and finished products:

Single-Laboratory Validation Parameters

This method validation work was conducted following the guidelines of AOAC INTERNATIONAL criteria for single- laboratory validation (12).

Specificity

Chromatograms from the blank and placebo runs were overlaid with the chromatograms from the standard and sample to show that there was no significant interference at the retention times (RTs) of the peaks of aloins A and B and aloe-emodin (Figure 2). No significant interfering peaks were present at the RTs of aloins A and B and aloe-emodin from the placebo and blank solution. Two aloin compound peaks from the standard injection were observed at about 10.4 and 11.3 min. No interference peaks were observed for the injections (from the bottom upwards) of solvent blank, placebo of powder product,

(

)

×

DF

sampleconcn

aloinA aloin B aloe-emodin g gor ppm µ

(

)

mL ( )

samplewt g mL µ

=

(

)

g ( )

where sample concn = the sample concentration from the standard curve and DF = the dilution factor for the sample.Achromatogram of the aloin A and B standard (80 ppb) at 380 nm is shown in Figure 2016.09A . A chromatogram of the aloe-emodin standard (80 ppb) at 430 nm is shown in Figure 2016.09B .