A simple and portable multi-colour light emitting diode based photocolourimeter for the analysis of mixtures of five common food dyes

• Published in: Food chemistry 2011-07, Vol.127 (1), p.308-313
• Main Authors: Sorouraddin, Mohammad-Hossein, Rostami, Ali, Saadati, Masoud
• Format: Article
• Language: English
• Subjects: Absorbance; Absorbance ratio; Biological and medical sciences; Detectors; Devices; Double-beam photometer; Food dyes; Food industries; Foods; Fundamental and applied biological sciences. Psychology; Light emitting diode; Light-emitting diodes; Photometers; Portability; Quinoline; Simultaneous determination; Wavelengths
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2010.12.124

► An LED-based photometer was devised and applied for determination of food colourants. ► The device is easy to construct and operate and the cost is considerably low. ► A simple approach was developed for resolving the binary and ternary mixtures. ► The method is based on the difference of the absorptivity ratios. ► The method is appropriate to limit data obtained by the LED based devices. A simple and cheap spectrophotometric method for the simultaneous determination of Tartrazine, Quinoline Yellow, Sunset Yellow, Carmoisine and Brilliant Blue in commercial food products with the aid of a portable double beam photocolourimeter are described. The method is based on the difference of the absorptivity ratios at maximum absorbances of two compounds or three compounds. The proposed device uses red–green–blue light-emitting diode as light source and light dependent resistor as detector. A programmable microcontroller sequentially turns the emitters on, receives the signals followed by calculating the absorbance and displaying it on a liquid–crystal display. The photometer is capable of performing absorbance measurements in a single wavelength as well as in three wavelengths sequentially, allows its application in simultaneous analysis of binary and ternary mixtures based on the differences of absorbance ratios in two and/or three wavelengths. The method was validated against a standard HPLC method and the results obtained were in a good agreement with those of HPLC method.