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- Posts: 2
- Joined: Mon Mar 20, 2017 8:34 pm
Good afternoon,
I am facing difficulties in the analysis of vitamin D3 identification, in mineral matrix in the case (calcium carbonate), I am following the methodology of USP 40-NF35, follow the method.
Mobile phase: n-Hexane and isopropyl alcohol (99:1)
Standard solution: 2 µg/mL of USP Ergocalciferol RS or USP Cholecalciferol RS in n-hexane
System suitability solution: Heat a volume of Standard solution at 60° for 1 h to partially isomerize vitamin D (ergocalciferol or cholecalciferol) to its corresponding precursor.
Sample solution: Weigh NLT 20 Tablets, and grind the Tablets to a fine powder. Transfer the equivalent of 20 µg of cholecalciferol or ergocalciferol to a container having a polytef-lined screw cap. Add 8 mL of dimethyl sulfoxide and 12 mL of n-hexane, and shake for 45 min on a wrist-action shaker with tubes in a water bath maintained at 60°. Centrifuge for 10 min, withdraw the hexane layer by means of a pipet, and transfer to an evaporation flask. Add 12 mL of n-hexane to the dimethyl sulfoxide layer, mix on a vortex mixer for 5 min, and again withdraw the hexane layer by means of a pipet, and add to the evaporation flask. Repeat this extraction with three additional 12-mL portions of n-hexane, adding the hexane extracts to the evaporation flask. Evaporate the combined hexane extracts in vacuum at room temperature to dryness. Dissolve in and dilute the residue in a volume of n-hexane to obtain a concentration of 2 µg/mL.
Detector: UV 265 nm
Column: 4.6-mm × 15-cm; 5-µm packing L8
Flow rate: 1 mL/min
Injection size: 100 µL
I am facing difficulties in the analysis of vitamin D3 identification, in mineral matrix in the case (calcium carbonate), I am following the methodology of USP 40-NF35, follow the method.
Mobile phase: n-Hexane and isopropyl alcohol (99:1)
Standard solution: 2 µg/mL of USP Ergocalciferol RS or USP Cholecalciferol RS in n-hexane
System suitability solution: Heat a volume of Standard solution at 60° for 1 h to partially isomerize vitamin D (ergocalciferol or cholecalciferol) to its corresponding precursor.
Sample solution: Weigh NLT 20 Tablets, and grind the Tablets to a fine powder. Transfer the equivalent of 20 µg of cholecalciferol or ergocalciferol to a container having a polytef-lined screw cap. Add 8 mL of dimethyl sulfoxide and 12 mL of n-hexane, and shake for 45 min on a wrist-action shaker with tubes in a water bath maintained at 60°. Centrifuge for 10 min, withdraw the hexane layer by means of a pipet, and transfer to an evaporation flask. Add 12 mL of n-hexane to the dimethyl sulfoxide layer, mix on a vortex mixer for 5 min, and again withdraw the hexane layer by means of a pipet, and add to the evaporation flask. Repeat this extraction with three additional 12-mL portions of n-hexane, adding the hexane extracts to the evaporation flask. Evaporate the combined hexane extracts in vacuum at room temperature to dryness. Dissolve in and dilute the residue in a volume of n-hexane to obtain a concentration of 2 µg/mL.
Detector: UV 265 nm
Column: 4.6-mm × 15-cm; 5-µm packing L8
Flow rate: 1 mL/min
Injection size: 100 µL
