Analysis of Banned Dyes in Eggs by LC-MS/MS

The color of egg yolks is considered an indicator of the nutritional value and freshness of eggs. Eggs with darker yellow-orange tones in their yolks are the most in-demand. For this reason, it has been determined that some egg producers feed their chickens with feed containing various synthetic dyes in an attempt to produce eggs in the desired shade. This situation can be revealed by investigating the presence of prohibited dyes in eggs. In this study, quantitative determination of specific prohibited dyes in egg yolk was performed. A Shimadzu LCMS-8040 triple quadrupole mass spectrometer was used for high-sensitivity quantitative analysis (Figure 2). Due to the high scanning speed of the LCMS-8040, simultaneous analysis of four sudan dyes and p-red dye is made possible. All of these dyes were detected at low ppb levels with high selectivity and good reproducibility, despite the presence of the egg matrix. Sudan and p-red dyes contain synthetic industrial dyes in groups such as Sudan I, II, III, IV. In 1987, the International Agency for Research on Cancer investigated the safety of Sudan I, II, III and IV dyes and concluded that it was not possible to classify these dyes as carcinogenic to humans. Although there is some evidence that sudan dyes can cause cancer in test animals and cause genetic damage, there is currently insufficient evidence that these dyes can cause cancer in humans. The four sudan dyes and para red dye studied in practice are shown in Figure 3.

Analysis Method

Matrix-Matched Calibration Curve A Qu-EChERS kit was used for extraction in the sample preparation phase. The collected supernatant was passed through a C-18 SPE cartridge and eluted with acetonitrile. This eluent was used to prepare matrix-matched dilutions in the range of 1 ppb–100 ppb.

LC/MS/MS Analysis

LC/MS/MS conditions are given in Table 1. The LCMS-8040 is a suitable instrument for food safety analysis with its ultra-fast polarity switching and ultra-fast MRM and high-sensitivity measurements. These features allow the detection of multiple compounds with different ionization tendencies in a single injection without loss of sensitivity.

Results

Analysis of sudan and para red dyes was performed in both aqueous matrix and egg yolk matrix. Optimization was performed using the automatic MRM optimization feature of MRM LabSolutions software. The analysis was also checked against blank controls for interferences. Background interferences were minimized through method optimization. Figure 4 shows the result of simultaneous analysis of 5 dyes in egg yolk. Quantitative results are presented in Table 4. A LOQ value of 1 ppb was obtained for each of the 5 dyes in both aqueous and egg yolk matrices. • A method was developed for high-sensitivity simultaneous analysis of four sudan dyes and p-red dye in egg yolk. • A LOQ value of 1 ppb was obtained for each of the 5 dyes using matrix-matched calibration standards with accuracy above 0.99 and sensitivity between 90–110%. • An analytical method was developed to minimize background interference and thereby increase sensitivity.

References [1] Rashi Kochhar, Shailendra Rane, Shailesh Damale, Deepti Bhandarkar, Shruti Raju, Ajit Datar, Pratap Rasam and Jitendra Kelkar, Shimadzu Analytical (India) Pvt. Ltd., ASMS 2015 Poster TP 334

Murat Yayla Senior Chemist MS Group Manager Ant Teknik Cihazlar