Showing papers on "Tartrazine published in 1999"

Color stability of denture base acrylic resins in three food colorants.

Abstract: Statement of problem . Three commonly used artificial dyes in food technology are erythrosine, tartrazine, and sunset yellow. Purpose . The color stability of 5 commercially available denture base acrylic resins (QC-20, Meliodent, Trevalon, Trevalon High, and Lucitone) was studied in vitro. Methods . The specimens were exposed to 3% erythrosine, tartrazine, and sunset yellow solutions at 23°C±1°C. Color changes were determined with a computer-controlled spectrophotometer. Five specimens from each material were processed, and initial color measurements were made after 1, 3, and 6 months of exposure to the staining solutions. Finally, the color stability was quantitatively measured again, and color differences (†E) were calculated. Results . For the observations made in 1, 3, and 6 months intervals, the specimens that exhibited the least color change were in the sunset yellow solution. The greatest color changes observed according to the National Bureau of Standards unit system were Lucitone (2.71) in erythrosine solution, Lucitone (2.54), QC-20 (1.71) in tartrazine solution, and QC-20 (1.66) in sunset yellow solution. The changes in the other acrylic resins in the 3 solutions were slight and at trace level. Conclusions . All materials tested were acceptable from the standpoint of color stability for long-term exposure to these food colorants.

Determination of benzidine in the food colours tartrazine and sunset yellow FCF, by reduction and derivatization followed by high-performance liquid chromatography.

Abstract: Free and bound benzidine, a non-sulphonated aromatic amine (NSAA), were determined in the food colours tartrazine and sunset yellow FCF. Bound amines were released by reducing with sodium dithionite, then total NSAAs were extracted into chloroform, transferred to aqueous acid solution and diazotized with sodium nitrite before coupling with 2-naphthol-3,6-disulphonic acid, disodium salt (R-salt). Coloured benzidine and aniline derivatives (BZDRS and ANRS) were analysed using reversed-phase ion pair high-performance liquid chromatography (HPLC) and an absorbance detector set at 548nm. Levels of total benzidine were similar to those reported in studies conducted in the USA, and ranged from < 5 to 270ng/g. Total aniline was also determined (0.2-188 mug/g). Recoveries of benzidine with this method were found to be lower than expected (average ca 46%), but were reproducible. Detection limits were 15-20ng BZDRS/g (3-4ng benzidine/g). Mass spectrometry (LC-MS) was evaluated for identifying and determining purity ...

Rapid spectrophotometric method to resolve ternary mixtures of Tartrazine, Quinoline Yellow and Patent Blue V in commercial products

Abstract: A very simple spectrophotometric method is described for resolving ternary mixtures of the food dyes Tartrazine (E-102), Quinoline Yellow (E-104) and Patent Blue V (E-131) by using the second derivative of the spectra with measurements at zero-crossing wavelengths. Calibration graphs are linear up to 20.0 mg/L of Tartrazine, up to 20.0 mg/L of Quinoline Yellow and up to 6.4 mg/L of Patent Blue V. Repeatability and reproducibility studies (with the Students’s and F tests) were achieved for two series of nine standards for each dye showing no significant differences at the 95% confidence level. Detection limits of 0.0526, 0.0164 and 0.0034 mg/L were obtained for Tartrazine, Quinoline Yellow and Patent Blue V, respectively. This method was used for determining synthetic mixtures of these colorants in different ratios and it was successfully applied to four commercial products without previous separation step. The results found in commercial products were compared with those obtained by an HPLC method and very similar values were found for both methods.

Nuclear magnetic resonance investigations of azo-hydrazone, acid-base equilibria of FD&C Yellow No. 5 (tartrazine)

Abstract: Azo-hydrazone, acid-base equilibria were examined for the water-soluble, food color additive FD&C Yellow No. 5 (Y5), with the observation of dynamic NMR effects near, and at, pH 10, where the food colorant converts from a predominantly hydrazone tautomer (acidic to moderately basic pH) to a prevailing azo-anion resonance hybrid (high pH). Potentiometric titrations further indicate that the p Ka of Y5 is ca. 10. These data suggest that observed NMR line broadening is due to slow proton transfer between a hydrazone-NH and water.

Determination of synthetic colorants and natural carmine in wines

Abstract: Methods were developed for the determination of synthetic colorants and natural carmine (E120) in wines. The synthetic colorants studied were tartrazine (E102), quinoline yellow (E104), sunset yellow (E110), azo ruby (E122), amaranth (E123), ponceau 4R (E124), and erythrosine (E127). The colorants were extracted using solid-phase extraction (SPE) with NH2 cartridges. The extracted colorants were then analysed by high-performance liquid chromatography (HPLC). The compounds were identified by comparing the spectrum of extract with spectra in a UV-vis spectral library of known food colorants. The detection limits in red wine ranged from 0.1 mg/l to 0.2 mg/l. Diode array detection and library search makes the method very effective in identifying forbidden colorants in wines. SPE is sufficiently effective in separating and concentrating colorants from wine. The effect of added colorants, e.g. azo ruby (E122), amaranth (E123) and tartrazine (E102) on the UV-vis spectra of red and white wines were studied. The added colorants could be identified in this way but not as accurately as by the HPLC method.