5. AOACSPDSMethods-2018AwardsV3

10

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

Table 11. Linearity and range standard solutions

Table 17. Regression analysis for aloe-emodin R 0.999980 y -Intercept –461.6635 Slope 248.2991

1 ppm aloin A and B and aloe-emodin standard, mL

Linearity standards concn, ppb

Final volume, mL

10 20 40 80

2.0 2.0 2.0 2.0 4.0 5.0

200 100

Empower System Suitability software. The curves for aloins A and B and aloe-emodin had an R of >0.998. Tailing factors for the aloin A and B and aloe-emodin peaks were <2.0. The theoretical plates of the peaks for aloins A and B and aloe- emodin were >10000 (Table 19).

50 25 25 10

160 500

LOD

Table 12. Linearity test for aloin A Concn, ppb

The LOD of the method was determined by measuring S/N from a spiked placebo sample from herbal aloe concentrate mango at 10 ppb level. The LOD met acceptance criteria of not more than 10 ppb. The S/N for aloins A and B and aloe-emodin were 11.8, 9.8, and 7.8, respectively. The LOD of this method was 10 ppb. (This approach was very conservative because a typical LOD level requires a S/N of about 3.)

Peak area

10.10 20.20 40.39 80.79

845

1947 3829 7451

161.57 504.92

14641 46321

Table 13. Regression analysis for aloin A R

0.999964 14.03195 91.62991

y -Intercept

Slope

Table 14. Linearity test for aloin B Concn, ppb

Peak area

10.04 20.09 40.17 80.34

760

Figure 4. Linearity plot of aloin A.

1584 3143 6348

160.69 502.15

12947 40416

Table 15. Regression analysis for aloin B R

0.999957 –65.10327 80.62814

y -Intercept

Slope

Figure 5. Linearity plot of aloin B.

Table 16. Linearity test for aloe-emodin Concn, ppb

Peak area

10.37

2386

20.74

4896

41.47

9774

82.94

19977

165.89

40316

518.40

128405

Figure 6. Linearity plot for aloe-emodin.