12 / 97
nitine esters to form free carnitine than an acidic hydrolysis thereby giving higher
results this is seen as ok because we desire to measure the total content of car-
nitine.
Sample: NIST SRM 1845A
Measuring range:
The measuring range in this validation covers the interval: LOQ
–
1000 ng/g.
Samples containing concentration higher than the highest standard will be reana-
lysed with a more fitting sample size and/or dilution leading to a concentration in-
side the standard range.
Limit of detection / quantification:
LOD has been determined by treating a standard at low level (9 ng/g) as a sam-
ple, the reason this approach has been used is that it has been impossible to find
a natural sample containing carnitine at a level near the expected limit of detec-
tion.
The sample was analysed as a 10 replicates measurement on the same day, the
standard deviation (S
r
) has been calculated from these results. See appendix 3.
LOD is calculated as 3 x S
r
and LOQ as (10 x S
r
).
The limit of detection and quantification for carnitine is calculated to:
LOD: 0,9 ng/g
LOQ: 3,0 ng/g
LOQ in samples as mg/kg is calculated from an aliquot of 20 g sample (maxi-
mum) extracted into 110 g extraction solution. 10 g extraction solution is diluted to
250 g, (this sums up to a total dilution factor of 137,5).
Carnitine in samples:
LOQ: 0,4 mg/kg
Robustness:
The robustness of the method has been evaluated on the following critical pa-
rameters; extraction time and saponification time.
Extraction time:
The robustness test has been performed on a milk powder and a pet food con-
Carn-06 - Validation Report
FOR ERP USE ONLY
DO NOT DISTRIBUTE