Determination of hydroquinone in beverages using colorimetric and electrochemical sensors on paper-based device.

Hydroquinone (HQ) is a phenolic compound used in industry processes. We aim to demonstrate a rapid and simple procedure for the determination of HQ. This work has developed two techniques, including colorimetric and electrochemical sensors on paper-based devices. Firstly, we have developed the colorimetric detection for the rapid screening test of HQ using 1.5% 4-(dimethylamino) benzaldehyde with alkaline condition (5 M NaOH). Under suitable conditions, the calibration curve between the intensity and HQ concentration was in the range of 50-500 mg L -1 . Then, we developed a multi-walled carbon nanotube/graphene oxide/copper/palladium/platinum (MWCNT/GO/Cu/Pd/Pt) onto a screen-printed carbon electrode (SPCE). The optimal amount of MWCNT/GO/Cu/Pd/Pt nanomaterial is 2 mg for HQ detection. The linear concentration range was found in the range 1 to 20 mg L -1  and a detection limit was found to be 0.40 mg L -1 (3.6 µM) for HQ. Moreover, the proposed device can be applied to determine HQ in real samples and is inexpensive technique, portable, and low consumer time.