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4.
Specificity
–
Specificity was demonstrated in multiple ways. All results obtained were acceptable; therefore there are no
concerns of method specificity within the constraints outlined in the current SMPR (2014.002).
a.
Testing of samples not fortified with fructan.
–
Only 6 of 19 the SPIFAN matrices were fortified with fructan
material. Two additional matrices were also spiked here with fructan commodity provided for the purpose of
SLV experiments for SPIFAN. Therefore 11 different blank sample matrices were tested to demonstrate the
specificity of the method. No fructose was detected in those samples after taking them through part 2 of this
method. Their respective chromatograms are shown in Appendix B.
b.
Additional testing of products containing other potential interferences
–
The range of samples tested contained
the following potential chromatographic/method interferences (chromatograms also shown in Appendix B):
i.
Products containing maltodextrin
ii.
Products containing GOS
iii.
Analysis of Milk or Soy based products
1.
Products containing hydrolysate protein.
5.
LOQ
–
LOQ was empirically demonstrated by spikes of nominal 0.03% fructan in a 9% sucrose solution to approximate
a worst case RTF sample with extremely high sucrose (traditionally a high sucrose to fructan ratio is a problem for
fructan testing methodologies). Average recovery was 102% (n=9, three replicates in each of three independent runs) as
per Table 2-8. Therefore the method LOQ is set at 0.03% fructan on an as-fed basis.
Conclusions
This method for fructan analysis was developed incorporating various aspects of existing methods (1-3). It has the advantage
of simplified prep relative to Cuany et al, and a lower LOQ than existing AOAC methods (1 & 2). It has demonstrated
applicability to both milk and soy based products containing scFOS, oligofructose, or inulin. The addition of GOS to the
products does not cause a specificity concern (non fructan fortified SPIFAN matrices were also tested with no fructan detected,
see Appendix B for example chromatograms). It is believed to be applicable to all matrices and fructans within the scope of
SMPR 2014.002.
References
(1)
J. AOAC Int. 80, 1029 (1997).
(2)
J. AOAC Int. 83, 356 (2000).
(3)
Cuany D, Bénet T, Austin S. J AOAC Int. 2010 Jan-Feb; 93(1):202-12.
(4)
Thermo/Dionex,
Tech Note 21
, Optimal Settings for Pulsed Amperometric Detection of Carbohydrates Using the Dionex
ED40 Electrochemical Detector.
(5)
Thermo/Dionex,
Product Manual p/n 04078,
Borate Trap Column.
Fos-04 (February 2016)
FOR ERP USE ONLY
DO NOT DISTRIBUTE