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Table 18. Ruggedness test for aloins A and B and aloe-emodin Analyst a , b Product Aloin A, ppb Aloin B, ppb

Aloe-emodin, ppb

Analysis date

Difference

ND c

NA d

Analyst 1 Analyst 2 Analyst 1 Analyst 2

Aloe vera WL 5×, lot 1 Aloe vera WL 5×, lot 1 Aloe vera gel 200×, lot 2 Aloe vera gel 200×, lot 2 Herbal aloe concentrate mango, lot 3 Herbal aloe concentrate mango, lot 3 Herbal aloe powder mango, lot 4 Herbal aloe powder mango, lot 4

ND ND

ND ND

December 10, 2010 January 12, 2011

ND

346.8 363.5

333.2 362.6

23.5 27.5

December 10, 2010 4.7% for aloin A

January 12, 2011

8.5% for aloin B 15.7% for aloe-emodin

Analyst 1

ND

ND

ND

December 10, 2010

NA

Analyst 2

ND

ND

ND

January 12, 2011

Analyst 1

201.2

205.0

<20

December 10, 2010 2.5% for aloin A

Analyst 2

206.3

217.5

<20

January 12, 2011

5.9% for aloin B

NA for aloe-emodin a  Analyst 1 used the following equipment: HPLC No. 4, Waters Alliance System, Model 2695, Serial No. J07SM4025A and a Phenomenex Synergi Hydro-RP column, 80 A, 4 µ, 250 × 4.6 mm (Part No. 00G-4375-E0), Serial No. 553344-13. b  Analyst 2 used the following equipment: HPLC No. 3, Waters Alliance System, Model 2695, Serial No. J07SM4030A and a Phenomenex Synergi Hydro-RP column, 80 A, 4 µ, 250 × 4.6 mm (Part No. 00G-4375-E0), Serial No. 524451-39.

c  ND = None detected. d  NA = not available.

Table 20. Aloin A and B and aloe-emodin stock standard solution stability 80 ppb working standard Concn expected, ppb Concn found, ppb Recovery, % Aloin A 83.89 81.73 97.4 Aloin B 75.96 75.03 98.8 Aloe-emodin 76.80 80.52 104.8

LOQ

The LOQ of the method was determined by measuring S/N from a spiked placebo sample of herbal aloe concentrate mango at the 20 ppb level. The LOQ met acceptance criteria of not more than 20 ppb. The S/N for aloins A and B and aloe-emodin were 16.7, 14.3, and 16, respectively. The LOQ of this method was at 20 ppb. (This approach was very conservative because a typical LOQ level requires a S/N of about 10.)

Conclusions

Aloin A and B and Aloe-Emodin Stock Standard Stability

The linearity, specificity, precision, accuracy, ruggedness, and LOD and LOQ test results demonstrated that this test method for the determination of aloins A and B and aloe-emodin by HPLC in raw materials and finished products is suitable for its intended use.

The stock standard solution of aloinsAand B and aloe-emodin that was initially prepared was stored in a refrigerator (2–8°C). After 19 days, the stock standard solution was removed from the refrigerator and a fresh stock standard solution was prepared. Both stock standard solutions were diluted and tested. Table 20 shows the recovery of the refrigerated standard calculated against the fresh standard to determine the stability of the stock standard solution of aloins A and B and aloe-emodin. Based on the above test results, the stock standard solution of aloins A and B and aloe-emodin was stable for 19 days when stored in the refrigerator at 2–8°C. An expiration date of 2 weeks (14 days) will be assigned to the stock standard when stored refrigerated at 2–8°C. Table 19. Typical system suitability results (precision test) Analyte R Tailing factor Plate count Aloin A 0.999990 1.0 81176 Aloin B 0.999843 1.0 67627 Aloe-emodin 0.999964 1.1 417385

Acknowledgments

We would like to acknowledge Steven Dentali and Andrew Shao for helpful discussions.

References

(1) Pugh, N., Ross, S.A., Elsohly, M.A., & Pasco, D.S. (2001) J. Agric. Food Chem. 49 , 1030–1034. doi:10.1021/jf001036d (2) Aysan, E., Bektas, H., & Ersoz, F. (2010) Eur. J. Obstet. Gynecol. Reprod. Biol. 149 , 195–198. doi:10.1016/j .ejogrb.2009.11.019 (3) Dagne, E. (1996) Bull. Chem. Soc. Ethiop. 10 , 89–103 (4) International Aloe Science Council (2017) Version 1.0, (search term: “aloin limit”), http://www.iasc.org/SearchResults .aspx?Search=aloin+limit (5) J. AOAC Int. 99 , 318(2016). doi: 10.5740/jaoacint. SMPR2015.016