Page 17 - Analytical method for food addtives

2 Analytical methods for food additives

summarised in Table 1.2. The majority of published methods are for the
determination of sunset yellow in liquid matrices i.e. drinks, therefore further
development of extraction procedures is necessary to adapt methods for other food
matrices i.e. chocolate products.
A suitable method for the analysis of sunset yellow in soft drinks was
2
collaboratively trialled. The method consisted of a quantitative extraction, as ion
pairs with cetylpyridinium chloride, from aqueous solutions into n-butanol. The
sunset yellow was analysed using reversed phase, ion pair gradient elution HPLC
with diode array detection. A summary of the procedure for this method is given in
the Appendix and the performance characteristics are given in Table 1.3.
A reverse phase HPLC method for the analysis of six dyes including sunset
yellow was applied to a number of food samples (three beverages, gelatin dessert
3
and a strawberry flavoured syrup) and found to be suitable. Separation was
performed on a Nova-Pak C18 column using methanol–NaH PO /Na HPO , pH 7,
2 4 2 4
buffer solution (0.1 M) as mobile phase with an elution gradient system and UV–
vis detection at 520 nm. Under optimum conditions (details given in the Appendix)
dyes were eluted in 4 min. A summary of the procedure for this method is given in
the Appendix and a summary of the statistical parameters in Table 1.4. This
method has also been used to compare the results for the simultaneous determina-
tion of dyes in foodstuffs when new methods have been developed i.e. by capillary
zone electrophoresis. 16

1.3 Recommendations

For sunset yellow analytical methods using extraction followed by spectoroscopy 1
are in place for a full range of beverages, sauces, starchy and fatty foods. There are
no recent publications for sunset yellow in chocolate products, therefore this is an
area that requires method development.

1.4 References
1 Pearson’s Composition and Analysis of Foods, 9 ed. Kirk R and Sawyer R, Longman
Scientific, Harlow, (1989).
2 ‘Determination of synthetic coal-tar dyes in soft drinks, skimmed milks and cakes:
collaborative trial’, Dennis J, Chapman S, Brereton P, Turnbull J, Wood R. J. Assoc.
Publ. Analysts (1997) 33, 161–202.
3 ‘A reverse phase HPLC method to determine six food dyes using buffered mobile phase’,
BerzasNevado J J, GuiberteauCabanillas C and ContentoSalcedo A M. Analytical
Letters (1998) 31(14), 2513–2535.
4 ‘Simultaneous determination of preservatives, sweeteners and colourings in soft drinks
by ion-pair reversed phase HPLC’, Zhou S, Li J. Sepu (1990) 8(1), 54–56. [Chinese]
5 ‘Rapid determination of preservatives, sweeteners, food colourings and caffeine by
HPLC’, Ren Y, Gao Z, Huang B. Shipin Yu Fajiao Gongye (1990) 1, 72–75. [Chinese]
6 ‘Simultaneous determination of nine food additives in beverages by high-performance
liquid chromatography (HPLC)’, Wu F, Zhang P. Sepu (1992) 10(5), 311–312. [Chinese]
7 ‘Determination of eight synthetic food colorants in drinks by high-performance ion