AOAC Final Action Methods in 2018

(f)  Calculation of trans vitamin K 1 in a sample: C pTrans = ( C c × 10.0 × R )/( S × P )

between the cis and trans isomers ( see Figures  2015.09B–D ). Check the integration of the cis and trans vitamin K 1 peaks. Cis vitamin K 1 elutes 1 to 3 min before trans vitamin K 1 depending on the analytical column used. If the peak areas of the same standards injected before and after a set of samples have changed by more than 7%, the system was not equilibrated and the data are not acceptable. (c)  Calculation of trans vitamin K 1 standard concentration: where T is the trans vitamin K 1 fraction, A 1 is the cis vitamin K 1 peak area, and A 2 is the trans vitamin K 1 peak area. The  trans vitamin K 1 fraction is calculated for all standards, and the calculated trans vitamin K 1 fraction for all standards is averaged together ( T a ) and used to calculate the trans vitamin K 1 concentration of all standards. (d)  Trans vitamin K 1 standard concentration: C ST = C S × T a where C ST is the concentration of trans vitamin K 1 in the working standard C S in µg/L; C S is the working standard concentration in µg/L; and T a is the average trans vitamin K 1 fraction. (e)  Preparation of standard curves .—For each working standard concentration, average the trans peak areas from each two consecutive sets of standard injections. Prepare a standard curve by performing a linear least-squares (regression) on trans concentration versus averaged trans peak areas. A standard curve must have a coefficient of determination, r 2 , of 0.999 or better to be acceptable. ) A A A T + 2 2 ( 1 =

where C pTrans is the concentration of trans vitamin K 1 in µg/kg, C c is the concentration of trans vitamin K 1 in the injected sample determined from the standard curve in µg/L, 10.0 is the dilution volume of the sample in mL, R is the final dilution weight of a product reconstitution in g (if necessary), S is the sample size in g, and P is the weight of product that is reconstituted in g (if necessary). ( g )  Total vitamin K 1 in a sample .—If required, total vitamin K 1 in a sample can be calculated:

C

pTrans

C

=

pTotal

T

sample

where C pTotal is the concentration of total ( cis + trans ) vitamin K 1 in µg/kg; C pTrans is the concentration of trans vitamin K 1 in the sample µg/kg; and T sample is the trans vitamin K 1 fraction in the sample, F ( c ). References: J. AOAC Int . 98 , 1382(2015) DOI: 10.5740/jaoacint.15-130 (First Action) J. AOAC Int . 102 , 222(2019) DOI: 10.5740/jaoacint.18-0155 (Final Action) AOAC SMPR 2014.001 J. AOAC Int . 98 , 1036(2015) DOI: 10.5740/jaoac.int.SMPR2014.001 Posted: October 12, 2015 (First Action); February 2018; February 2019 (Final Action); 2019 (Codex adoption)

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