Development of porous laser-induced graphene electrode modified with poly(phenol red) for detection of zinc in rice grains.

Abstract

ABSTRACTThis study presents the development of a highly sensitive and selective electrochemical sensor based on a laser-induced graphene (LIG) electrode modified with poly(phenol red) (P(PhR)@LIG) for the determination of zinc nutrition in rice grains using square wave anodic stripping voltammetry (SWASV). Zinc (Zn) is an essential micronutrient for human health, and its deficiency is a major global issue. Rice, being a staple food for a large portion of the global population, is an important dietary source of zinc. Its biofortification holds potential to alleviate zinc deficiency, particularly in regions where rice is the primary food source. However, accurate and reliable methods for measuring zinc content in rice are critical for assessing the effectiveness of biofortification.The P(PhR)@LIG electrode was fabricated using CO2 laser to induce graphene formation on a polyimide substrate, followed by the electropolymerization of phenol red (PhR) onto the LIG surface. The physicochemical properties of the modified electrode were characterized using scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), and Raman spectroscopy, confirming successful modification of the electrode surface and enhanced electrochemical properties due to the additional adsorption sites provided by the P(PhR) film. Optimization of electrochemical performance was achieved by adjusting key parameters such as pH, accumulation time, preconcentration potential, and SWV settings. The sensor demonstrated a linear detection range from 30 to 3000 ?g L-1 with a limit of detection (LOD) of 14.5 ?g L-1. The sensor exhibited excellent reproducibility with relative standard deviations (RSDs) consistently below 5% and good anti-interference properties from metal ions, anions, and glucose present in rice grains. In real sample analysis, the sensor showed recovery rates ranging from 98.7% to 103.9%, consistent with results obtained from the ICP-OES method. This research highlights the potential of the P(PhR)@LIG sensor as a cost-effective, portable, and highly sensitive tool for on-site zinc detection in agricultural products, especially for monitoring zinc biofortification in rice and ensuring food safety.

????????????????????????????????????????????????????????????????????????????? ??????????????????????????????????????????????????????????????????????(????????) (P(PhR)@LIG) ????????????????????????????????????????????????????????????????????????? ?????????????????????????????????????????????????????? ?????????????????????????????????????????????? ???????????????????????????????????????????????????????????????????? ????????????????????? (Biofortification) ?????????????????????????????????????? ????????????????????????????????????? ???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? P(PhR)@LIG ??????????????????????????????????????????????????????????????? ?????????????????????? (LIG) ?????????????????????????????????????????????? (PhR) ?? LIG ??????????????????????????????????????????????????? P(PhR)@LIG ??? ??????????????????????????????????????? ???????????????????????????????????? ??????????????????????? ????? P(PhR) ???????????????????? LIG ????????????????????????????????????????????????????? ?????????????? P(PhR) ????????????????? Zn2+ ????????????????????????????????????????????????????????????????????????????????????? ???? ????? ????????????????? ??????????????????????? ??????????????????????? SWV ??????????????????????????????????????????????????????????????????????????????? 30 ??? 3000 ?g L-1 ?????????????????????????? 14.5 ?g L-1 ????????????????????????????????????????? ???????????????????????????????????? (RSD) ???????? 5% ???????????????????????? ????????? ???????? ?????????????? ????????????????????????????????????????????????????????????????????? (% recovery) ?????? 98.7% ??? 103.9% ???????????????????????????????????? ICP-OES ?????????????????????????????????????????????????? P(PhR)@LIG ????????????????????? ????????? ?????????????? ?????????????????????????????????????????? ????????????????????????????????????????????????????????????????????????????