Potential of glucose measurement in soil and food sample using low molecular weight <i>O</i>-(2-hydroxyl)propyl-3-trimethylammonium chitosan chloride nanoparticle-glucose oxidase immobilised on a natural fibre membrane

<div><p>Low, medium and high molecular weights <i>O</i>-(2-hydroxyl)propyl-3-trimethylammonium chitosan chloride nanoparticles (L-, M- and H-<i>O</i>-HTCC NP) have been synthesised and used to immobilise glucose oxidase on eggshell membranes for glucose biosensing. Among these <i>O</i>-HTCC NP-based biosensors, L-<i>O</i>-HTCC NP provides the highest sensitivity to glucose with a linear response of 0.012–0.60 mM and a detection limit of 12 μM (<i>S</i>/<i>N </i>= 3). The effect of L-<i>O</i>-HTCC NP and enzyme loading ratio, pH, temperature and phosphate buffer concentration on the sensitivity of the biosensor was studied in detail. The biosensor exhibits fast response time (40 s), good repeatability (3.0%, <i>n</i> = 10) and storage stability (95% of initial sensitivity after 1-year storage). Common interferents including acetic acid, DL-α-alanine, L-ascorbic acid, butyric acid, citric acid, DL-cysteine, ethanol, folic acid, glycine, lactic acid, lactose, propionic acid, sodium benzoate and sucrose do not cause significant interference on the L-<i>O</i>-HTCC NP biosensor. The recoveries 88.3%–102% and 102%–116% and relative standard deviations (RSDs) 3.90%–5.56% and 1.25%–3.00% are respectively, for the soil and food sample analyses. The proposed biosensor method has been applied to determine glucose in soil and food samples with good accuracy and recovery, inferring that it has potential for detection and quantification of diversified samples of different matrices. Finally, it has successfully monitored the changes of glucose contents in soil samples at various incubation times, demonstrating its potential use in environmental and geochemical analysis.</p></div>