D-728

Water Soluble Determination by HPLC using UV-Vis Spectroscopy

Section D — Laboratory Operations and Specifications Revision 2 10 pages

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1.0 Purpose 
 
 The purpose of this procedure is to describe a method for the quantitative analysis and spectral
 
 identification of water soluble vitamins in finished products and raw materials using HPLC and
 
 UV/VIS spectrophotometry. 
 
 2.0 Scope 
 
 This procedure has been validated for use in identifying and quantifying seven common water
 soluble vitamins. The quantitation and/or identification can be completed individually or
 
 multiple vitamins can be quantified within a single chromatogram. Some excipients and dietary
 
 ingredients used in the finished products can interfere with the analysis of individual vitamins
 which may require the use of an alternate wavelength that does not exhibit interference.
 
 3.0 Responsibility 
 
 3.1. ‘It is the responsibility of QC Chemists to understand and work within the guidelines of
 this procedure. 
 
 3.2 It is the responsibility of QC Laboratory Management to implement this procedure and
 
 to ensure that the procedure is being followed. 
 
 3.3. It is the responsibility of QC Laboratory Management and/or Analytical Development to
 
 keep this procedure aligned with current practices. 
 
 4.0 Definitions 
 
 4.1 Ascorbic Acid — Vitamin C 
 
 4.2 Niacin — Vitamin B3 
 
 4.3 Thiamine — Vitamin Bi 
 
 
 

[SOP 

 Standard Operating Procedure SOP No Rev No 
 Page 
 Water Soluble Vitamin Determination by HPLC Using D-728 
 2 of 10 
 UV/VIS Spectroscopy 
 4.4 Riboflavin — Vitamin B2 
 
 4.5 Folic Acid — Vitamin M or Vitamin Bo 
 
 4.6 Cyanocobalamin — Vitamin Bi2 
 
 4.7 Pyridoxine — Vitamin Be 
 
 4.8 H2O — Water (= 18.2 MQ-:cm) 
 
 4.9 ACN -— Acetonitrile 
 
 4.10 H3POa — Phosphoric Acid (85%) 
 
 4.11 K2HPOs«-— Potassium Phosphate Dibasic 
 
 4.12 Na2EDTA-2H20 — Ethylenediaminetetraacetic acid disodium salt dihydrate
 
 4.13 Na2B407-10H20 — Sodium borate decahydrate 
 
 4.14 HCI — Concentrated hydrochloric acid (~37%) 
 
 4.15 WSMV -— Water Soluble Multi-Vitamin 
 
 4.16 CofA — Certificate of Analysis 
 
 4.17 USP — United States Pharmacopeia 
 
 4.18 HPLC — High Performance Liquid Chromatography 
 
 4.19 UV/Vis — Ultraviolet and Visible Spectroscopy 
 
 5.0 References 
 
5.1 MV-LAB-12-011, Protocol, Water Soluble Vitamins in Multicomponent Formulations

 Determination by HPLC 
 
 Dud RPT-23-0063, Report, Extend Pyridoxine Linearity for D-728 
 
 33 NCR-23-0010, Product Specific Method Optimization, Riboflavin in SEC00448 and
 SCT00447 
 
 
 

[SOP 

 Standard Operating Procedure SOP No Rev No 
 Page 
 Water Soluble Vitamin Determination by HPLC Using D-728 
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 UV/VIS Spectroscopy 
 6.0 Supplies 
 
 6.1 Chemicals: all reagents are HPLC grade or better. Vitamins when used as standards
 should be USP traceable when available. 
 
 6.1.1 H20 
 
 6.1.2 ACN 
 
 6.1.3. H3PO4 
 
 6.1.4 K2HPOs(MW 174.18) 
 
 6.1.5 NagZEDTA-2H20 
 
 6.1.6 | Na2Bs407-10H20 
 
 6.1.7. HCl 
 
 6.1.8 Reference Standards 
 
 6.1.8.1 Ascorbic Acid 
 
 6.1.8.2 Niacin 
 
 6.1.8.3 Thiamine 
 
 6.1.8.4 Riboflavin 
 
 6.1.8.5 Folic Acid 
 
 6.1.8.6 | Cyanocobalamin 
 
 6.1.8.7. Pyridoxine 
 
 6.1.8.8 | Pantothenate 
 
 6.1.8.9 Biotin 
 
 6.2 Glassware 
 Note: Low actinic glassware recommended for riboflavin. Glassware may also be
 
 shielded from light using aluminum foil. 
 
 
 

[SOP 

 Standard Operating Procedure SOP No | Rev No 
 Water Soluble Vitamin Determination by HPLC Using | 2-728 9 Page 
 4 of 10 
 UV/VIS Spectroscopy 
 6.2.1 HPLC vials, 12mm X 32mm with screw cap enclosures w/ septa. 
 
 6.2.2 Scintillation vials 
 
 6.2.3. 1L mobile phase container 
 
 6.2.4 50mL, 100mL, and 500mL volumetric flasks 
 
 6.3. Disposables 
 
 6.3.1 200uL, ImL, and 10mL pipette tips 
 
 6.3.2 Disposable plastic luer lock syringe- 3mL, 6mL or 10mL 
 
 6.3.3 Nylon syringe filters, 25mm or larger diameter. 
 
 6.3.4 Weigh boats 
 
 6.3.5 1.5mL and 2.0mL Eppendorf centrifuge tubes 
 
 6.4 Equipment 
 
 6.4.1 Suitable gradient HPLC system consisting of a pump, autosampler, column oven
 
 and UV detector with a chromatographic data handling system 
 
 6.4.2 Analytical Balance 
 
 6.4.3 Vortex 
 
 6.4.4 Stir Plate 
 
 6.4.5 Wrist Action Shaker 
 
 6.4.6 Eppendorf centrifuge 
 
 6.4.7 200uL, 1mL and 10mL pipettes 
 
 7.0 Preparation of Mobile Phase, Dissolution Buffer, Samples and Standards 
 
 7.1 Mobile Phase A (0.1% H3PO4 in H20) - add 1.0 mL H3POq to 1000 mL H20.
 
 7.2 Mobile Phase B (0.1% H3PO4 in ACN) - add 1.0 mL H3POs to 1000 mL ACN.
 
 7.3. WSMV Dissolution Buffer (0.01M K2HPOs, used for all analytes except riboflavin) - add
 
 1.7418g of K2HPOs to 1000 mL H20, and mix well to dissolve. 
 
 
 

[SOP 

 Standard Operating Procedure SOP No | Rev No 
 Water Soluble Vitamin Determination by HPLC Using | D-728 9 pan 
 UV/VIS Spectroscopy 
 
 7.4 Riboflavin Dissolution Buffer (90 mM EDTA + 125 mM Borate, pH=8.0) — Dissolve
 
 33.5 g of Na2EDTA-2H20 and 47.7 g of Na2B407-10H20 in 1 L of H20 by stirring under
 
 gentle heat, adjust to pH 8.0 using HCl. 
 
 7.5 Standard Preparation 
 
 7.5.1 Linear range — all standard and sample preparations must be within the linear
 
 range of the method. The values listed below are valid for a 20 uL injection
 volume. If another injection volume is used, the range should be corrected for
 
 injection volume (e.g. if the range is 0.01 — 0.1 mg/mL at 20 uL injection
 volume, then the range would be 0.02 — 0.2 mg/mL at 10 wL injection volume).
 
 Toll Ascorbic Acid (270 nm) — 0.1 mg/mL — 1.0 mg/mL 
 
 Fidel Cyanocobalamin (225 nm) — 0.00025 mg/mL — 0.1 mg/mL 
 
 TAs Folic Acid (225 nm) — 0.003 mg/mL — 0.04 mg/mL 
 
 7.5.1.4 Niacin (230 nm) — 0.0025 mg/mL — 1.0 mg/mL 
 
 Yoshaad Pyridoxine (225 nm) — 0.0003 mg/mL — 1.0 mg/mL 
 
 7 d16 Riboflavin (225 nm) — 0.0025 mg/mL — 0.06 mg/mL 
 
 7.5.1.7 Thiamine (225 nm) — 0.0025 mg/mL — 1.0 mg/mL 
 
 7.5.2 For low concentration standards and samples, it may be necessary to first
 prepare a higher concentration stock and subsequently dilute to the final
 
 concentration. The suggested maximum concentration of stock solutions with
 consideration to solubility are listed below. 
 
 Louael Ascorbic Acid - 1.0mg/mL 
 
 7.5.2.2 Cyanocobalamin - 0.1mg/mL 
 
 1323 Folic Acid - 0.1mg/mL 
 
 7.5.2.4 Niacin - 1.0mg/mL 
 
 L525 Pyridoxine - 1.0mg/mL 
 
 
 

[SOP 

 Standard Operating Procedure SOP No | Rev No 
 Water Soluble Vitamin Determination by HPLC Using | 2-728 9 Bis 
 UV/VIS Spectroscopy 
 
 7.5.2.6 Riboflavin - 0.1mg/mL 
 
 7.5.2.7 Thiamine - 1.0mg/mL 
 
 7.5.3 Use the actual purity from the CofA or the standard certification for the vitamin
 reference material for calculations. The Stock Standard Preparation reflects
 
 100% content for the vitamin assayed. 
 
 7.5.4 Standards are prepared by weighing no less than the minimum weight of the
 analytical balance then bring up to two thirds of the final volume in an
 
 appropriate volumetric flask using Dissolution Buffer. Dissolution can be
 
 achieved with the use of a wrist action shaker or sonicator. Avoid long
 sonication times for heat labile compounds such as thiamine, ascorbic acid, and
 
 cyanocobalamin. The standard may require dilution to final volume to achieve
 complete dissolution. 
 
 lie Dilutions are prepared using Dissolution Buffer. Dilutions can be made using
 
 volumetric flasks or using 10mL, I1mL and 200uL variable pipettes. Specific
 
 standard working concentrations will approximate the concentration expected to
 be found in the product being tested based on the sample dilution and calculated
 
 from label. Dilutions can be prepared directly in HPLC vials.
 
 7.6 Sample Preparation 
 
 7.6.1 Specific sample testing details are provided in each products profile. If a
 specific testing details section is not available, then follow preparation
 
 procedure as described below, maintaining concentration within the linear range
 
 of this method. 
 
 7.6.2 For solid form finished products, recommended sample preparation- 20 or more
 dosage units pooled and ground by mortar and pestle as necessary.
 
 7.6.3 Based on the average fill weight per dose weigh a portion of the parent sample
 
 to achieve the target analyte concentration for the selected sample volume giving
 consideration to the solubility and linearity requirements. 
 
 
 

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 Standard Operating Procedure SOP No | Rev No 
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 Water Soluble Vitamin Determination by HPLC Using | 2-728 9 
 7 of 10 
 UV/VIS Spectroscopy 
 7.6.4 Samples can be dissolved or diluted in Dissolution Buffer at any volume no less
 than 25mL. To manage large volumes the sample can be initially dissolved in a
 
 smaller volume that is within the solubility range and a portion diluted to bring
 the analyte concentration into the range of measurement. The final diluted
 
 sample must be filtered or centrifuged before analyzing by HPLC.
 
 7.6.4.1 If analysis is required at a concentration below the validated linear
 
 range, a minimum of a three point standard curve is required and the
 coefficient of determination (R’) must be no less than 0.99.
 
 Additionally, the sample concentration must be within the
 demonstrated range of linearity for result to be valid. At very low
 
 concentrations spectral identification may not be suitable and 3-D
 spectra of the chromatogram may be used to visually determine that
 
 no interference is present at the wavelength used in the quantitative
 
 analysis. 
 
 7.6.5 Optimizing the dissolution process for a given matrix can be characterized
 during system suitability. The recommended starting point is dissolution in 2/3
 
 final volume for 30 minutes on a wrist action shaker. Sonication and other
 methods of dissolution may be used with proper verification of recovery and
 
 stability. Avoid long sonication times for heat labile compounds such as
 
 thiamine, ascorbic acid, and cyanocobalamin. 
 
 7.6.6 Particulate must be removed from working sample prior to injection. Particulate
 can be removed by filtration using a plastic syringe coupled with a 0.2.M to
 
 0.45uM nylon syringe filter. Discard at least the first 0.5mL of filtrate before
 collecting a portion for analysis. Particulate can also be removed by
 
 centrifuging for 3 minutes at 6000rpm. 
 
 8.0 Test Conditions 
 
 8.1 Gradient (acceptable for all target analytes) 
 
 Time %A %B Gradient type 
 
 
 

[SOP 

 Standard Operating Procedure SOP No | Rev No 
 
 Water Soluble Vitamin Determination by HPLC Using | -728 9 Seok 
 UV/VIS Spectroscopy 
 
 0.00 98 2 0 
 
 2.80 98 2 0 
 
 2.81 90 10 step 
 
 7:30 50 50 linear 
 
 7.40 98 2 linear 
 
 10.00 98 2 0 
 
 8.2 Isocratic (only for ascorbic acid, niacin, pyridoxine, and thiamine)*
 
 Time %A %B Gradient type 
 
 0.00 98 2 0 
 
 4.00 98 2 0 
 
 * wash column with H2O/ACN (10/90) as outlined below after use when using isocratic
 
 8.3 Column- Luna C5, 5um, 150mm X 4.6mm 
 
 8.4 Flow Rate- 1.0mL/min 
 
 8.5 Recommended spectral range for identification- 205nm to 500nm 
 
 8.6 Injection volume- 20uL (other volumes may be used to optimize separation provided that
 
 the standard and sample are within the range of linearity). 
 
 8.7 Column Temperature- 45°C 
 
 8.8 Approximate Retention Times 
 
 8.8.1 Ascorbic Acid — 2.4 min (isocratic) 
 
 8.8.2 Cyanocobalamin — 7.0 min (gradient) 
 
 8.8.3. Folic Acid — 7.0 min (gradient) 
 
 8.8.4 Niacin (nicotinic acid) — 2.2 min (isocratic) 
 
 8.8.5 Niacin (niacinamide) — 1.8 min (isocratic) 
 
 
 

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 Standard Operating Procedure SOP No Rev No 
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 Water Soluble Vitamin Determination by HPLC Using D-728 
 9 of 10 
 UV/VIS Spectroscopy 
 8.8.6 Pyridoxine — 1.7 min (isocratic) 
 
 8.8.7. Riboflavin — 7.3 min (gradient) 
 
 8.8.8 | Thiamine — 1.2 min (isocratic) 
 
 9.0 Recommended Sequence 
 
 9.1.1 Make at least 2 injections of the diluent. 
 
 9.1.2 Make five (5) injections of Standard Solution. 
 
 9.1.3. Make a single injection of each Sample Preparation. 
 
 9.1.4 Make a single injection of the Standard Solution after every six (6) samples and
 
 at the end of the run. 
 
 9.2 System Suitability Requirements 
 
 9.2.1 The %RSD of the first five (5) standard injections is NMT 5.0%.
 
 9.2.2 The %RSD of all standard injections is NMT 5%. 
 
 9.3 Column Wash and Storage 
 
 9.3.1. Wash the column with H20:ACN (50:50) at 1 mL/min for at least 30 min.
 
 9.3.2 Store the column with H20:ACN (50:50). 
 
 10.0 Example Calculation 
 
 10.1 0% assays=a SR ReU x sWt Vts e t tda a x “P ., PV e spyi r . a , 2 S t S 2e 100
 
 Ry Sample peak area 
 
 Rs Mean standard peak area 
 
 Wtgtq Weight of reference standard in mg 
 
 Veta Volume of the standard preparation accounting for dilutions in mL
 
 P Purity of the reference standard in decimal format 
 
 SA Sample amount in mg 
 
 
 

[SOP 

 Standard Operating Procedure SOP No | Rev No E 
 Water Soluble Vitamin Determination by HPLC Using | D-728 9 10 ae 
 UV/VIS Spectroscopy 
 
 Vsp. Volume of the sample preparation accounting for dilutions in mL
 
 SS Serving size: Weight of a single dosage unit in mg, or 1 for raw materials.
 
 LA Label amount in mg per dose or 1 for raw materials 
 
 11.0 Revision History 

| Rev | Date | Description of Changes | CCR # | By |
|-----|----------|------------------------|-------|----|
| 2 | 05/20/13 | Updated format. Added calculatii ons for di4 rect 9% label measurement. Added more detailed instructions on sample preparation. | 13-237 | B. Johns |
| 3 | 03/12/14 | Increased readability with new format. Standardized wording. Added pantothenate to the list of vitamins. | 14-0191 | Bo Johns |
| 4 | 09/08/16 | Updated to new SOP format. Added expanded information on current practices. | 16-0823 | N. Zhang |
| 5 | 07/03/18 | Updated SOP to match current Ion practices. Added Biotin to list of approved vitamins. Update to reflect current practices, remove biotin and pantothenate | 18-0219 | J. Maignan |
| 6 | 04/15/22 | 38 analytes, add recommended sequence, add column wash and CC- storage, add retention times, add option to reduce wavelength range used for spectral match. | 22-0182 | S. Sassman |
| 7 | 12/20/22 | Added test details section. Minor edits. CC- | 22-0475 | J. Sassman |
| 8 | 10/19/23 | ae range for pyridoxine, allow long gradient for all CC- | 23-0521 | S. Sassman |
| 9 | 10/31/23 | Add new Dissolution Buffer for riboflavin. CC- | 23-0537 | S. Sassman |