Choline in infant formula and adult nutritionals by ion chromatography and suppressed conductivity: First Action
Insights
A new ion chromatography method accurately determines choline in infant formula and adult nutritionals. This validated method meets performance standards for reliable analysis of essential nutrients.
Area of Science:
- Analytical Chemistry
- Food Science
- Nutritional Analysis
Background:
- Choline is a vital nutrient in infant formula and adult nutritional products.
- Accurate quantification of choline is essential for product quality and regulatory compliance.
- Existing methods may require validation for diverse nutritional matrices.
Purpose of the Study:
- To validate a single-laboratory method for choline determination in infant formula and adult nutritionals.
- To establish the method's performance against Standard Method Performance Requirements (SMPRs).
- To gain AOAC Official First Action status for the developed analytical procedure.
Main Methods:
- Microwave-assisted acid hydrolysis for choline release from diverse matrices (powder, ready-to-feed).
- Ion chromatography (IC) using a Dionex IonPac CS19 column for separation.
- Suppressed conductivity detection for quantitative choline measurement.
Main Results:
- Method validated across 17 SPIFAN matrices, meeting SMPRs.
- High recoveries (93.1-100.7%) and low RSDs (<6.7%) demonstrated.
- Accurate determination of NIST SRM 1849a (10.2 ± 0.2 mg/100 g) with 1.8% RSD.
- Limit of Detection (LOD) at 0.009 mg/100 g and Limit of Quantitation (LOQ) at 0.012 mg/100 g, well below requirements.
Conclusions:
- The ion chromatography method with microwave-assisted hydrolysis is robust and accurate for choline determination.
- The method successfully passed single-laboratory validation and was approved as AOAC Official First Action.
- This validated method provides reliable choline quantification for infant formula and adult nutritional products.
Abstract:
Single-laboratory validation (SLV) data from a method for the determination of choline in infant formula and adult nutritionals by ion chromatography (IC) and suppressed conductivity were generated and presented to the Stakeholder Panel on Infant Formula and Adult Nutritionals (SPIFAN) Expert Review Panel (ERP) at the AOAC Annual Meeting held in Las Vegas, NV, during September 30 to October 3, 2012. The ERP reviewed the data and concluded that the data met the standard method performance requirements (SMPRs) established and approved the method as AOAC Official First Action. At the ERP's request, a second, full SLV was performed on 17 SPIFAN matrixes that included fortified and placebo products. Prior to IC analysis, microwave-assisted acid hydrolysis was used to digest and release bound choline from powder and ready-to-feed (RTF) infant formula and adult nutritional samples. Following hydrolysis, separation of choline from common cations was achieved on a Thermo Scientific Dionex IonPac CS19 column followed by suppressed conductivity detection. Total choline was measured and reported as the choline ion in mg/100 g reconstituted material or RTF as-is. The system was calibrated over the analytical range specified in the SMPR (2-250 mg/100 g). Recoveries of spiked samples at 50 and 100% of the fortified choline amounts ranged from 93.1 to 100.7% with RSDs < or = 6.7% for product containing < 2 mg/100 g and < or = 4.1% for product containing 2-100 mg/100 g. Accuracy for the National Institute of Standards and Technology Standard Reference Material 1849a was determined over a 6-day interval and found to be 10.2 +/- 0.2 mg/100 g calculated as the reconstituted powder with an RSD of 1.8%. The LOD was determined to be 0.009, and the LOQ 0.012 mg/100 g, well below the SMPR requirements of 0.7 and 2 mg/100 g, respectively. Repeatability RSDs over the range of the assay (2-200 mg/100 g) ranged from 1.0 to 5.93%
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