SPDS Lutein and Turmeric ERPs

AOAC O

FFICIAL

ETHODS

NALYSIS

(2013)

UIDELINES

FOR

IETARY

UPPLEMENTS

AND

OTANICALS

Appendix K, p. 15

cancel out. (The Youden ruggedness trial or fractional factorial

experiment was designed for this outcome.) Similarly,

Effect of B and b

[(x1 + x2 + x5 + x6)/4] – [(x3 + x4 + x7 + x8)/4] = K

4B/4 – 4b/4 = K

Effect of C and c

[(x1 + x3 + x5 + x7)/4] – [(x2 + x4 + x6 + x8)/4] = L

4C/4 – 4c/4 = L

Effect of D and d

[(x1 + x2 + x7 + x8)/4] – [(x3 + x4 + x5 + x6)/4] = M

4D/4 – 4d/4 = M

Effect of E and e

[(x1 + x3 + x6 + x8)/4] – [(x2 + x4 + x5 + x7)/4] = N

4E/4 – 4e/4 = N

Effect of F and f

[(x1 + x4 + x5 + x8)/4] – [(x2 + x3 + x6 + x7)/4] = O

4F/4 – 4f/4 = O

Effect of G and g

[(x1 + x4 + x6 + x7)/4] – [(x2 + x3 + x5 + x8)/4] = P

4G/4 – 4g/4 = P

Perform the eight determinations or runs carefully using the

assigned factor level combinations and tabulate the values found.

Then unscramble the 7 factors and obtain the effect of the assigned

factor as the last number. It is important to use the combination of

subscripts as assigned for proper interpretation.

Expt. Found, %

Factors

1.03

J (A) = 4A/4 – 4a/4 = 4.86 – 5.14 = –0.28

1.32

K (B) = 4B/4 – 4b/4 = 4.79 – 5.21 = –0.42

1.29

L (C) = 4C/4 – 4c/4 = 4.86 – 5.14 = –0.28

1.22

M (D) = 4D/4 – 4d/4 = 5.05 – 4.95 = +0.10

1.27

N (E) = 4E/4 – 4e/4 = 4.92 – 5.08 = –0.16

1.17

O (F) = 4F/4 – 4f/4 = 4.95 – 5.05 = –0.10

1.27

P (G) = 4G/4 – 4g/4 = 4.69 – 5.31 = –0.62

1.43

These values are plotted on a line. In this case they are more

or less uniformly scattered along the line, but some attention

should be paid to the extremes. Factor D, the highest positive

value represents a difference in solvent, as expected, and this

factor has to be investigated further to determine if the high

values represents impurities or additional active ingredient. The

extreme value of factor G suggests that the extraction should be

conducted in the dark. As discussed by Youden, considerably more

information can be obtained by utilizing several different materials

and several independent replications in different laboratories, so

as to obtain an estimate of the standard deviation to be expected

between laboratories. Although the ruggedness trial is primarily a

method development technique, validation of the application of a

method to different matrices and related analytes can be explored

simultaneously by this procedure.

Comments not used (may be added later):

3.3 Calibration: Run standards from low to high to compensate

for any carryover. [Run in random order to compensate for drift

is more important than allowing for carryover which should not

occur.]

Independently made standards results in considerable random

error in the calibration curve and is in fact the major source of

random error in spectrophotometry. [Therefore a common stock

solution is the preferred way of preparing the individual standards.]

Version 54 contains revisions as a result of comments from

levanseler@nsf.org

and McClure. Outline:

I. Types and benefits of each method validation study without

reproducibility

II. Preparing for a Single-Laboratory Method Validation Study

III. Review of Performance Characteristics of a Method

IV. Errors

V. Calibration and Types

VI. Bias and Precision Estimations (no reference standard; no

reproducibility)

VII. Detection and Quantification Limits

VIII. Ruggedness