MOSH/MOAH in fish oil (LC-GC-FID and GCxGC-FID)

Method ring test P2605-MRT is designed for the quantification of MOSH and MOAH by means of LC-GC-FID and GCxGC-FID or similar methods. The participants are invited to apply both techniques to quantify MOAH and to report results related to both techniques. Data can be used for a method comparison of the two analytical methods. A separation of 1- and 2-ring systems from 3- and more-ring systems is not part of this ring test.

Limits of quantification of 5 mg/kg related to total MOSH resp. total MOAH are necessary for this method ring test.

1st sample:
A purified EPA/DHA omega-3 oil is used as raw material, which is expected to be low in interferences related to the analysis of MOSH and MOAH. The unspiked material is provided as blank material, while the test material is spiked with MOSH and MOAH. 

2nd sample:
A sample of a fish oil with significant amounts of interferences is provided as test material for training purposes. 

The 1st sample (with the low interferences) is considered to evaluate the performance of the laboratories in the test. The evaluation of the performance is summarised in the report and in the certificate.

The 2nd sample (with high interferences) is for training purposes only. The labs are asked to analyse the sample and to report the analytical results as well as the procedures for clean-up and for handling of the interferences. The aim behind the 2nd sample is to exchange knowledge for handling of challenging fish oil samples. The evaluation of the 2nd sample is summarised in a separate part of the report. 

Spiked levels are within the typical ranges of contaminations of fish oils. The results related to the spiked material are evaluated with respect to the comparability criterion (z-score) as well as with respect to the trueness criterion (70 to 120 % of the spiked level, as far as scientifically reasonable).

P2605-MRT is offered as a method ring test, which means,

• the evaluation is not limited to the pure statistical evaluation.
• the participants are asked to provide the chromatograms related to the test materials.
• the participants are asked to answer a questionnaire related to relevant aspects of the sample preparation and analysis. 

The chromatograms as well as the answers related to the questionnaire are summarised in separate parts of the final report. For reasons of fairness, only those participants, which provide details and chromatograms will receive these parts of the report. The data will help to identify shortcomings, built the basis for further discussion and thus help to enhance the quality of the applied method.