Selective carbon-based electrode modified with electrochemically molecularly imprinted poly-melamine (EMIP-M) for square wave voltammetry detection of TBHQ

Tertiary butylhydroquinone (TBHQ) is a phenolic additive typically added to food ingredients as a preservative. Generally, adding TBHQ to food ingredients enhances stability, especially for substances prone to oxidation. However, the Department of Health has restricted the use of TBHQ due to potential carcinogenic effects. This study developed a voltammetric method for TBHQ determination using Electrochemically Molecularly Imprinted Poly-Melamine (EMIP-M) modified Carbon Paste Electrode (CPE), further called CPE/EMIP-M. The measurement employed the Square Wave Voltammetry (SWV) technique at 10 Hz. CPE/EMIP-M showed linearity in concentration ranges of 1 μM – 10 μM; 10 μM – 100 μM and 100 μM – 1000 μM, with sensitivities of 0.0514 μA/μM (R 2 = 0.9978); 0.0275 μA/μM (R 2 = 0.9939), and 0.0093 μA/μM (R 2 = 0.9925), respectively. The limit of detection for TBHQ was 0.29 μM. The modified electrode also showed good stability in 40 measurements and remained selective even after increasing the interference concentration by about 200 times. The modified electrode was used for real sample analysis, and the results were compared to those obtained using the HPLC method. The TBHQ concentration in an instant noodle seasoning oil sample was 13.57 ± 0.48 mg/kg and 13.53 ± 0.08 mg/kg, obtained with voltammetric and HPLC methods, respectively. Statistical tests showed no significant difference between voltammetric and HPLC results, confirming that the developed method is reliable for TBHQ determination in food samples.