POSTERPRESENTATION
The existing European biotin method,
EN 15607 (2009)
was normalized on the basis of a
French inter-laboratory study organized in 2000 in accordance with ISO 5725-2. The
precision data were established thanks to different samples : breakfast cereals – infant milk
powder – nutritive orange juice – green peaswith ham (baby food) – lyophilized chicken soup.
The biotin contents varied from 15µg/100g to 200µg/100g.
Thismethod iswidelyused inEurope for the control of food labeling and health claims.
However, a lot of products available on themarket with a nutritional labelingmay show now
a lower content of biotin. It is also the case of many infant formula and adult nutritional
products.
So, our objective was to study the possibility to extend the scope of the existing method to
lower contentswith the aim to reach the LOQ fixedwithin theBiotin SMPR recently adopted
inGaithersburg at theAOAC-SPIFANmeeting (March 2014).
Twodifferent things have been realized :
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A collaborative study
was performedon nine sampleswith three laboratories (Aérial,
Aquanal, SCL) to re-evaluate the performance of theCENmethodwith a lower range :
The nine samples used for this study included a certified referencematerial SRM1849a and
four sampleswith a low biotin content ranged from 1.2 to 13µg/100g (infant formula powder
and liquid – adult nutritional formula).
-
An in-house validation study
(performed by theSCL)with a six points calibration curve
from 0,0015µg/ml to 0,150µg/ml.
On figure 1 you can see that, at a low concentration, the peaks of biotin and biocytin (which
can be also quantified) are clearly separated. You have to be aware that the calibration curve
follows a quadratic model. So you need a 5 points calibration curve. This is due to the
principle of the post-column binding reaction.
D-biotin is extracted from food after an enzymatic treatment and quantified byHPLCwith
post-column binding reaction.
The complexion of d-biotinwith avidin appears tobe very specific. On that account, this
protein, covalently bound to a fluorescentmarker, fluorescein 5-isothiocyanate, can be used
as a reagent for a post-column binding of d-biotin.
On figure 2 you can see that a low biotin content can be reachedwith thismethod. The
sample is a cream adult nutritional product (biotin : 3µg/100ml). But lower contents samples
have been quantified for this validation study.
On figure 3 you can see a comparaison of some samples analyzed by the three laboratories.
Just below you can also read themainvalidation data. TheSPIFAN requirements are reached.
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