| Structure Identification: |
| Shokuhin Eiseigaku Zasshi. 2002 Apr;43(2):110-3. | | Analysis of lac color in diets and feces of rats for toxicity studies.[Pubmed: 12092412] |
METHODS AND RESULTS:
An analytical method was developed for lac color in diets fed to rats and in the feces, and the contents of lac color were determined. After lac color was extracted with 0.05% sodium carbonate and 50% ethanol containing 0.02% sodium lauryl sulfate from the diets and feces, the extracted color solutions were analyzed by HPLC. The recoveries of lac color from diets spiked at 1.25, 5.00% and that from feces spiked at 5.00% were 85.6, 93.4% and 69.5%, respectively. Contents of lac color in diets prepared to contain 1.25 and 5.00% were 1.1 and 5.2%, and dose levels were confirmed by these results. Contents of lac color in feces of male and female rats given lac color were 127.8 mg/g and 138.6 mg/g, respectively.
CONCLUSIONS:
By comparing the HPLC chromatograms of laccaic acids in the diet with those in feces of rats, laccaic acid A, laccaic acid B, laccaic acid C and Laccaic acid E were detected in both, and their content ratios were approximately determined. | | J Mass Spectrom. 2003 Dec;38(12):1252-8. | | Identification of anthraquinone coloring matters in natural red dyes by electrospray mass spectrometry coupled to capillary electrophoresis.[Pubmed: 14696204] |
METHODS AND RESULTS:
Capillary electrophoresis with UV/visible diode-array detection (DAD) and electrospray mass spectrometric (ESI-MS) detection were used for the identification of anthraquinone color components of cochineal, lac-dye and madder, natural red dyestuffs often used by ancient painters. For the purpose of such analysis, ESI-MS was found to be a much more appropriate detection technique than DAD one owing to its higher sensitivity (detection limits in the range 0.1-0.5 micro g ml(-1)) and selectivity. The method developed made it possible to identify unequivocally carminic acid and laccaic acid A, laccaic acid B and Laccaic acid E as coloring matters in the examined preparations of cochineal and lac-dye, respectively. In madder, European Rubia tinctorum, alizarin and purpurin were found.
CONCLUSIONS:
The method allows the rapid, direct and straightforward identification and quantification of components of natural products used in art and could be very helpful in restoration and conservation procedures. |
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