@misc{9249451,
  abstract     = {{Vitamins are a common food supplement that humans digest in order to live a more healthy lifestyle. Dietary supplements, DS, are a popular branch within the food industry. There are rules and regulations regarding the manufacturing of DS. One such regulation within the EU is that the content labeled on the product has to be true. One way of controlling the reliability of the labeling is through quantification and validation with analytical methods.
 
In this paper fat soluble vitamins such as A, E and D3 found in food supplements bought online will be identified and quantified. 

A method validation of the calibration curves for all vitamins was made by measuring the precision, accuracy, LOD, LOQ and linearity. A residual plot was also conducted in order to further ascertain the linearity of the calibration curves. 

The sample preparation was conducted by homogenising the vitamins before dissolving them in 0,5 L cold methanol. The solutions were then sonicated for 30 minutes. Extractions of 10 ml were taken out and centrifuged for 15 minutes at 4 ° with a speed of 5000 rpm. Lastly the extractions were evaporated with N2. The dried samples of A, E and D3 were then reconstituted in 10, 15 and 1,5 ml of methanol each. 

The analysis was carried out in a RP-HPLC with a C18 column. A DAD was chosen as the detector with installed wavelengths that correlated to the maximum absorbances of the three fat soluble vitamins. The rate of the flow was isocratic with a value of 1ml/min. The temperature was set to 40 degrees. 

The method validations demonstrated good results regarding the accuracy of the calibration curve for vitamin E, for vitamin D3 the accuracy was overall good except at 1.5 mg/L. The precision measurements for vitamin E and D3 demonstrated a leap in the middle of the calibration curves alluding to some kind of error that had taken place. The linearity measurements were most successful for vitamin D3 compared to vitamin A and vitamin E. Vitamin A had the highest R2- value.
The LOD values for vitamin A, E and D3 were 0,43, 0,05 and 1,46 mg/L respectively. The LOQ values were 1,43, 0,15 and 4,88 mg/L. The average amount in µg/ g tablets for each vitamin was higher than what the manufacturer declared on the products. 

The report presented that it is possible to use RP-HPLC as an analytical method to quantify the vitamin content in supplements. However due to the poor method validation for the vitamins, the deviation of the determined amount in relation to the declared amount on the product, could not be thoroughly interpreted.}},
  author       = {{Abdiwahab Hussein, Samira}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Determination of vitamin A, E & D3 content labeled on food supplements. Analysis made with RP-HPLC-DAD}},
  year         = {{2026}},
}