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12

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39

Table 2-7

Method comparison

New method 997.08

1

999.03

2

Reference 3

Number of sample

preparations and analyses

needed to complete testing

1

3

3

1

Instrument Run time (min)

45

83x3=249 NAP

65

Can test samples with

sucrose:fructan ratio >3:1

Yes

No

Yes

Yes

Requires post-column

reagent addition

No

No

NAP

Yes

Applicable to FOS,

oligofructose, and inulin

Yes

Yes*

Yes*

Yes

Requires extraction step

No

Yes

Yes

Yes

Requires SPE

No

No

No

Yes

Requires dry-down

No

No

No

Yes

Requires knowledge of

commodity type for

accurate results**

No

Yes

Yes

Yes

Method bias for any

commodities

No

No

Yes

No

Uses borate trap

Yes

No

No

No

LOQ (% on RTF basis)

0.03%

(90.8-115%

recovery)

0.5% 0.5%

0.014%

(83-101%

recovery)

%RSD (Intermediate

Precision)

2.04-7.12% 5.79% 1.25% 4.22-8.37%

1

Stated method performance taken from Covance labs website effective 10/15/2010.

2

Stated method performance taken from Covance labs website effective 01/21/2005.

*Method accuracy compromised by usage of set DP factors of 4 and 10 (actual range

is from 3.7-30).

**Limits utility at a regulatory level where the type of material may be unknown or

testing for off-label adulteration may be desired. The new method circumvents this

via the qualitative ID methodology in Part 1.

Conceptually this methodology is similar to that of Cuany, et. al. (3) However several time savings are gained from the

elimination of extraction, SPE, and sample dry-down. An additional time savings is generated in a shorter instrument cycle

time (45 minutes versus 65 minutes). Some of this is due to the incorporation of a borate trap in place of a standard PA1

guard. Borate negatively impacts HPAEC-PAD chromatography, creating peak distortion and other issues previously

observed (3, 5). Furthermore, the addition of the internal standard (as suggested in 997.08) allows for a non-volumetric

dilution and a subsequent improvement in LOQ.

1.

Linearity

For the 43 standard curves examined no calibration errors greater than + 5% were observed (see figure 2-3).

As expected the largest errors were observed in the lowest level standards. However the pattern of errors does not

indicate any systematic trends.

Fos-04 (February 2016)

FOR ERP USE ONLY

DO NOT DISTRIBUTE