Table of Contents Table of Contents
Previous Page  315 / 407 Next Page
Information
Show Menu
Previous Page 315 / 407 Next Page
Page Background

AOAC Final Action Method 2016.02 (Biotin)

Page 9 of 16

Table 2016.02C: Retention times and correlation coefficients

Lab #

Retention Time (Min)

Correlation Coefficient (r

2

)

Biocytin

Biotin

Biocytin

Biotin

1

4.6

16.1

0.9981

0.9995

2

3.8

15.9

0.9996

0.9999

3

4.9

16.2

0.9987

0.9993

4

5.9

18.1

0.9983

0.9997

5

4.4

15.5

0.9997

0.9993

6

4.9

16.5

0.9995

0.9995

7

3.3

14.5

0.9990

0.9990

8

4.1

13.8

0.9991

0.9973

9

6.1

22.5

0.9998

0.9995

11

4.9

15.1

0.9995

0.9988

12

4.1

12.9

0.9990

0.9993

MLT Results and Statistical Evaluation

The biotin results from practice and MLT samples (Day 1 and 2) are given in Tables 2016.02D, E and F

respectively. Fourteen different product types were analysed in duplicate by nine laboratories which

includes two practice samples and 12 samples for MLT over two separate days. The practice samples were

analysed in duplicates and the blind coded duplicates were analysed during MLT on the same day by the

participants. Laboratories 10, 11 and 12 submitted results for practice samples only.

The results are closely comparable between the duplicates and among all the participants and all the data

have been used for statistical evaluation to calculate repeatability, reproducibility and HorRat. The

statistical analysis of the data was carried out using

International Study Workbook Version 2.1 for Blind

(Unpaired) Replicates

from AOAC International. The data as presented in the report as

µg/100g

were used

as such for statistical calculation with a Factor for Units of Measurement of 1.00E-08. The summary of

relative standard deviation of repeatability (RSD

r

) and reproducibility (RSD

R

) along with HorRat

performance ratios is tabulated in Table 2016.02G.

Relative Standard Deviation of Repeatability (RSD

r

)

Repeatability expresses the precision under the same operating conditions (intra-assay) over a short

interval of time. The AOAC SPIFAN SMPR 2014.005 for the biotin analysis specifies a maximum

repeatability standard deviation of not more than 6% for biotin levels greater than 1 µg/100g. The mean

RSD

r

of the matrices analysed in the study is 4.6% and is well within the limit of the SMPR. However MLT

samples 5 and 9 recorded slightly higher RSD

r

of 6.79% and 7.03% respectively. The duplicate results from

Lab 8 are causing the outlier for MLT sample 5 and removing the data from the lab bring the RSD

r

down to

5.68%. Similarly, the removal of duplicate data from Lab 9 will bring the RSD

r

of MLT sample 9 down to

5.81%. The removal of these values still leaves statistically significant duplicate sets (8 sets) for a valid

RSD

r

calculation. However the values are kept in the report as the overall repeatability meets the SMPR

criteria and the SLV demonstrated the repeatability precision before the present study.

Relative Standard Deviation of Reproducibility (RSD

R

)

Reproducibility expresses the precision among the laboratories. The relative standard deviation of

reproducibility (RSD

R

) exceeds the SMPR criteria of not more than 12% for all the 14 matrices analysed in

the study confirming the precision of the analytical method. The maximum RSD

R

noticed was 9.5% in the

MLT sample 1, which is partially hydrolysed milk based infant formula matrix. The reproducibility precision

confirms the suitability of the SPIFAN method AOAC 2016.02 as a strong candidate as a reference method

for global dispute resolution hence the inter-laboratory variation is minimal and exceeds the expectation of

the SMPR limits.

2016.02 (BIOTIN) FINAL ACTION REVIEW

FOR ERP USE ONLY

DO NOT DISTRIBUTE

207