Automated colorimetric determination of alpha-tocopherol

Area of Science:

• Clinical Chemistry
• Biochemical Analysis
• Analytical Methodology

Background:

• Accurate quantification of alpha-tocopherol (vitamin E) is crucial for assessing nutritional status and diagnosing related health conditions.
• Existing methods for alpha-tocopherol determination may be time-consuming or require larger sample volumes.
• Establishing reliable reference ranges is essential for interpreting clinical results across different demographic groups.

Purpose of the Study:

• To develop and validate a rapid, automated, and convenient procedure for determining alpha-tocopherol levels in biological samples.
• To assess the precision and accuracy of the developed automated method.
• To establish reference ranges for alpha-tocopherol in healthy adults, pregnant women, and infants, and to compare these with individuals having specific disorders.

Main Methods:

• Development of an automated analytical procedure for alpha-tocopherol determination.
• Evaluation of sample volume requirements (as little as 0.3 ml) and sample throughput (20 per hour).
• Assessment of within-batch and between-batch precision at various concentrations.
• Determination of alpha-tocopherol distribution in different populations and calculation of reference ranges.

Main Results:

• The automated procedure demonstrated high precision (e.g., 3.68% between-batch at 20 mg/l) with negligible carry-over.
• Alpha-tocopherol levels in healthy adults followed a log-normal distribution, with a calculated range of 4.0 to 16.0 mg/l.
• Elevated alpha-tocopherol levels were observed in pregnancy (6.7 to 24.0 mg/l), while infants showed a wide range (2.0 to 16.0 mg/l).
• Infants with disorders had lower alpha-tocopherol levels (1.2 to 8.3 mg/l) compared to healthy infants.
• Cord blood alpha-tocopherol was approximately one-fifth of the maternal level.

Conclusions:

• The developed automated method offers a rapid, precise, and convenient approach for alpha-tocopherol analysis in clinical settings.
• The study provides valuable reference ranges for alpha-tocopherol in diverse populations, aiding in clinical interpretation.
• Findings highlight variations in alpha-tocopherol levels during pregnancy and infancy, suggesting potential physiological or pathological influences.