5. AOACSPDSMethods-2018AwardsV3

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16  B rown & Y u : J ournal of AOAC I nternational V ol . 96, N o . 1, 2013

Table 6. Interlaboratory reported results for the ginseng test materials

Total ginsenosides, mg/g GCS-1 GCS-2 GCS-3 GCS-4 GCS-5 GCS-6 GCS-7 GCS-8 GCS-9 GCS-10 GCS-11 GCS-12

Laboratory/ test material a

1

45.9

45.6

99.3

101.0 20.3

60.2

59.7 94.4 99.4 53300 40200

41.5

2 b 3 b

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

4

45.2

44.0

99.0

99.5

14.3

59.5

58.9 89.9 91.6

51.2

35.7

38.0

91.2 c

51.8 c

5

43.4

42.1

99.9

17.5

64.1

61.0 103.0 103.0 58.9

43.0

6

42.9

43.4

94.5

96.5

14.7

54.8

57.3 88.6 89.2

46.9

34.4

34.7

7

46.3

46.9

101.9

103.3 17.2

61.5

60.3 99.9 96.4

52.6

38.8

38.9

8

46.7

46.3

104.0

107.0 16.0

62.7

62.4 99.8 98.7

55.6

41.1

39.7

9

42.1

41.9

92.1

93.3

14.9

55.4

54.1 86.4 87.4

60.1

41.5

41.0

10

49.1

49.4

108.4

108.3 18.1

62.5

65.8 100.1 102.4 64.7

40.4

39.7

11

47.7

48.0

101.1

100.8 20.0

63.3

60.0 98.9 97.7

58.6

39.0

40.1

12

45.2

45.4

98.5

101.0 15.4

59.9

58.7 101.0 97.8

51.6

36.3

36.6

13

47.2

47.0

104.0

106.0 15.8

59.4

59.1 96.1 96.1

49.8

37.7

38.3

14 36.9 a  Material codes: GIN-GCS-1 = P. quinquefolius powdered whole root; GIN-GCS-2 = P. quinquefolius powdered whole root; GIN-GCS-3 = P. quinque- folius powdered extract; GIN-GCS-4 = P. quinquefolius powdered extract; GIN-GCS-5 = P. quinquefolius powdered whole root tablet form; GIN- GCS-6 = P. ginseng powdered whole root; GIN-GCS-7 = P. ginseng powdered whole root; GIN-GCS-8 = P. ginseng powdered extract; GIN-GCS-9 = P. ginseng powdered extract; GIN-GCS-10 = P. ginseng powdered extract capsule form; GIN-GCS-11 = P. ginseng spiked in matrix blank; GIN-GCS-12 = P. ginseng spiked in matrix blank. b Laboratories that did not provide results. c Outlier. 44.2 45.1 99.6 100.0 13.4 59.6 60.4 95.8 94.7 51.6 38.3

flammable organic solvents; keep away from any sources of heat and open flames and use a fume hood during sample processing. ( a )  Solvents .—Acetonitrile, HPLC grade; methanol, HPLC grade; water, HPLC grade or equivalent. ( b )  Potassium phosphate monobasic (KH 2 PO 4 ) .—≥99% ACS reagent grade or equivalent. ( c )  Potassium hydroxide (KOH) .—≥99%ACS reagent grade or equivalent. ( d )  Extraction solvent .—For every 1000 mL of extraction solvent, mix 700 mL HPLC grade methanol and 300 mL HPLC grade water. Sonicate for 5 min. ( e )  MPA .—For every 1000 mL of MPA, 1000 mL HPLC grade water. Sonicate for 5 min. ( f )  MPB .—For every 1000 mL of MPB, mix 800 mL HPLC grade acetonitrile and 200 mL HPLC grade water. Sonicate for 5 min. ( g )  Basic hydrolyzing agent (5% KOH, w/v) .—For every 100 mL of basic hydrolyzing agent, weigh approximately 5 g (± 0.1 g) KOH and dilute with 100 mL HPLC grade water. Mix well. ( h )  Neutralizing agent (14% KH 2 PO 4 , w/v).— For every 100 mL of neutralizing agent, weigh approximately 14 g (± 0.1 g) KH 2 PO 4 and dilute with 100 mL HPLC grade water. Mix well. ( i )  Reference standard .—A batch of MGRS in HPLC grade methanol supplied by the NRC in the form of individual 0.5 mL amber glass ampules or alternative certified reference material can be used as standards. These standards are intended to be diluted to appropriate concentrations to serve as calibration standards and as retention time markers. The seven-point calibration concentration levels for the MGRS are listed in Table 3.

Preparation of Calibration Standard Solutions

Note: If not used immediately, all solutions should be stored at –20°C. When stored at 2–8°C, solutions are stable for 24 h. All solutions are diluted with HPLC grade methanol and mixed well. Note: Transfer solutions into microliter HPLC vial inserts with a pipette. Ensure that there are no air bubbles in the insert prior to injection. ( a )  Linearity 1 .—Pipet 50 uL MGRS into an HPLC vial. ( b )  Linearity 2 .—Pipet 400 µLMGRS and dilute the solution with 800 µL HPLC grade methanol. ( c )  Linearity 3 .—Dilute 700 µL Linearity 2 solution with 500 µL HPLC grade methanol. ( d )  Linearity 4 .—Dilute 700 µL Linearity 3 solution with 500 µL HPLC grade methanol. ( e )  Linearity 4a .—Dilute 700 µL Linearity 4 solution with 500 µL HPLC grade methanol. Note : This is only used to make Linearity 6, not for instrument calibration. ( f )  Linearity 5 .—Dilute 700 µL Linearity 4a solution with 500 µL HPLC grade methanol. ( g )  Linearity 6 .—Dilute 700 µL Linearity 5 solution with 500 µL HPLC grade methanol. ( h )  Linearity 7 .—Dilute 700 µL Linearity 6 solution with 500 µL HPLC grade methanol.

Preparation of Sample Test Solutions

( a )  Powdered raw materials and powdered extracts.— ( 1 ) Accuratelyweighallsamplesinto50mLconicaltubes.Use