515 SIMPLIFIED SALT-ASSISTED SOLVENT EXTRACTION relative standard deviation (RSD) was more than 12%. After a comprehensive comparison, 100% (v/v) methanol was chosen as extractant solvent for the liquid–liquid extraction. Ionic salt can cause salting out, destroying the three-dimensional network of silica, consequently improving the extraction efficiency and the filtration before injection. Different ions and additives of salt, including 0.1 g, 0.2 g, 0.5 g, 1.0 g, 2.0 g, and 5.0 g sodium chloride and 0.1 g, 0.2 g, 0.5 g, 1.0 g, 2.0 g, and 5.0 g magnesium sulfate were studied. One g magnesium sulfate was found to achieve the best recovery, which was related to the high ion potential of magnesium ions to some extent. It has been proven in many studies that ultrasound can improve extraction rate (13,14). Extraction time of 15, 30, 45, 60, and 90 min were evaluated, while ultrasonic frequency was 35kHZ constant. Finally, 30 min ultrasonic-assist at 35kHZ was selected. The temperature of the water bath can be increased if the ultrasonic time is too long. METHOD VALIDATION Quantificated method. One point method with external standard was used for quantification. Two standard solutions of different concentrations were used to calibrate each other. The A B Figure 2. HPLC chromatograms of notoginseng R1 (1), ginsenoside Rg1 (2), Re (3), Rb1 (4), and Rd (5). Figure 2A is the chromatogram of standards Figure 2B is the chromatogram of toothpastes containing notoginseng R1, ginsenoside Rg1, Re, Rb1, and Rd after extraction.

516 JOURNAL OF COSMETIC SCIENCE RSD of six injection times’ peak areas of standard solution 1 and their cross-calibration should not be higher than 2% (Table II). Accuracy, precision, and recovery. The recovery and repeatability varied from 84–101%, from 1.6–5.6%, respectively. Validation of precision also has been done considering intra- and inter-day variation. Data are listed in Table III. Analysis of samples. To evaluate the effectiveness of the established method in a larger range of toothpaste samples, analysis was applied to a total of 17 samples from different manufacturers and batches containing saponins (Table IV). The results showed that there was no significant difference between actual and claimed contents. CONCLUSION A selective and sensitive HPLC-UV method for the simultaneous determination of notoginseng R1, ginsenoside Rg1, Re, Rb1, and Rd in silica matrix toothpastes was developed and validated in this study. This method was successfully applied to 17 samples from different manufacturers and batches. Salt-assisted and ultrasound-assisted methods improved the extraction efficiency. The proposed method has the potential to be applied Table II RSD of Six Injection Times and SD of Cross-Calibration Saponins RSD of 6 injection times/% SD1→2 of cross-calibration/% SD2→1 of cross-calibration/% R1 0.25 0.41 0.41 Rg1 0.08 0.21 0.21 Re 0.10 0.12 0.12 Rb1 0.07 0.77 0.77 Rd 0.07 0.31 0.31 Table III Recovery, Repeatability, Reproducibility, and RSD of Toothpastes Spiked With Saponins (n = 6) Saponins Spiked/ mg kg−1) Founded/(mg kg−1) (RSD/%) Recovery/% D1 D2 D3 R1 320 282 (2.8) 275(2.6) 205(1.8) 86 400 344(1.8) 340(1.9) 332(2.1) 84 480 418 (5.6) 436(4.4) 427(5.5) 89 Rg1 320 310 (2.6) 291 (3.6) 298 (2.4) 94 400 356(1.6) 372(1.8) 360(1.6) 91 480 494 (5.6) 470 (2.7) 484(3.9) 101 Re 320 281 (2.9) 262 (2.6) 270 (2.6) 85 400 364(1.8) 348(1.6) 352(1.6) 89 480 408 (5.7) 417 (5.6) 427 (4.8) 87 Rb1 320 294(2.2) 291(2.1) 275(1.8) 89 400 370(2.1) 376(1.9) 356(2.6) 92 480 456 (5.4) 466(4.5) 460(5.1) 96 Rd 320 294(2.2) 298 (2.6) 301 (2.1) 93 400 366(2.0) 350(1.9) 355(2.3) 89 480 459(5.3) 475(5.0) 451 (4.9) 96