AOAC SPIFAN ERP & Working Group Method Reviews (July 10, 2019)

with the vitamin B 12

peak areas of the samples and verify that the 12 peak areas of the samples are within the range of the

extrapolated from the vitamin B 12 The concentration of vitamin B 12

standard curve prepared above. in each product can then be

vitamin B vitamin B

calculated.

12 peak areas of the standards. ( c ) Calculation of standard concentrations . WS = S w × P × A/200 where WS = working standard concentration in m g/L; S w

C

= C

× D

÷ ss × D 2

÷ V

p

i

1

where C p = product concentration in m g/kg; C i 12 concentration of the injected sample preparation extrapolated from standard curve in m g/L; D 1 = volume of the first dilution in mL (100 mL); ss = sample size in g; D 2 = volume of the second (final) dilution in mL; V = volume of filtrate loaded onto the cartridge in mL. For each set of samples, the control result must be within three DOI: 10.5740/jaoacint.CS2011_10 J. AOAC Int . 98 , 1655(2015) AOAC SMPR 2011.005 J. AOAC Int . 95 , 293(2012) DOI: 10.5740/jaoac.int.11-0441 * Method adopted by AOAC as an Official Method of Analysis SM and by the International Organization for Standardization as ISO 20634:2015. Posted: February 18, 2016 = vitamin B standard deviations of the control mean. References: J. AOAC Int . 95 , 313(2012)

= amount

of vitamin B

12 standard weighed in mg; P = purity of USP reference

standard in m g cyanocobalamin (vitamin B 12

)/mg of the standard; A

= aliquot of vitamin B 12

intermediate standard used (0.5, 1, 2, 3, 4,

or 5) in mL; and 200 = dilution volume in mL. ( d ) Preparation of standard curves .—At each standard concentration, average the peak area of the standard injected at the beginning of a set of samples with the peak area of the standard injected at the end of the set of samples. Prepare a standard curve by performing linear least squares (regression) on concentration versus the average peak area of the working standards. A standard curve must have a correlation of at least 0.999 to be considered acceptable for sample calculations. ( e ) At each working standard concentration, the peak areas of standards injected at the beginning and end of a set of samples should not increase or decrease by more than 10%. ( f ) Calculation of vitamin B 12 concentrations in samples.— The vitamin B 12 concentration in each injected sample preparation is

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