8 / 97
Eurofins Lab. LTD., Wolverhampton: SOP CHROM/341-Choline in pet foods by
ion chromatography with conductivity detection.
The quantification by LC-MS/MS is based on the analytical concepts of the follow-
ing two articles.
STARKEY et AL. J.AOAC INT. 91,1,2008,130-142.Single-Laboratory Validation
of a Liquid chromatographic/Tandem Mass Spectrometric Method for the Deter-
mination of Free and Total Carnitine in Infant Formula and Raw Ingredients.
Brief method description:
The sample is shaken in a mixture of water and methanol thereby extracting car-
nitine including their phosphorylated forms. An aliquot is treated with potassium
hydroxide solution at elevated temperature for 4 hours thereby converting the
phosphorylated forms to free carnitine. The mixture is neutralised and deuterered
internal standard is added. Quantification is done by LC-MS.
Statistics:
In the current validation report, a p-value < 0.05 is considered statistically signifi-
cant. Consequently, confidence intervals (CI) are calculated at a confidence level
at 95 %. Paired t-testing is performed on normal distributed raw data. Data which
is not within the normal distribution is clearly marked within the text.
Matrices:
This method can be used for quantification of free and/or total carnitine in the fol-
lowing matrices:
Food and feed.
Supplements, premixes and raw products.
Milk powder and nutritional formulas.
Animal feed / pet food (dry and wet).
Specificity:
The specificity has been evaluated by examining chromatograms of natural sam-
Carn-06 - Validation Report
FOR ERP USE ONLY
DO NOT DISTRIBUTE