In this work, an electrochemical platform was developed for detection of D-pencillamine utilizing highly responsive molecularly imprinted polymers (MIPs). This platform operates on a ratiometric principle and is constructed on nitrogen-doped porous carbon nanosheets (N-PCNS) derived from zeolite imidazolate frameworks (ZIF-12) in the presence of saturated solution of zinc sulfate. Subsequently, silver nanoparticles (Ag) were introduced onto the surface of N-PCNS/GCE to enhance conductivity and surface area, and serve as a standard signal. The MIP layer was formed on the Ag@N-PCNS/GCE surface through o-phenylenediamine (o-phen) electro-polymerization in the presence of the D-pencillamine (D-PAN) as a template. Detection of D-PAN relies on measuring I_D-PAN/I_Ag response ratio employing differential pulse voltammetry (DPV). This ratio exhibits a linear correlation with the concentration of D-PAN in …

A novel fluorometric method for the determination of L-asparaginase, an enzyme crucial in cancer therapy and food industry applications, is presented. This sensitive and selective approach utilizes L-asparagine and two pH-sensitive carbon dots (blue-N-CDs and red-N-CDs) as probes. The interaction between L-asparagine and L-asparaginase liberates ammonia, causing an increase in pH. This pH change simultaneously decreases the fluorescence of blue-N-CDs while enhancing the emission of red-N-CDs, enabling ratiometric detection of L-asparaginase. Comprehensive characterization of both carbon dots and investigation of their response mechanism towards L-asparaginase were conducted using ultraviolet–visible spectrophotometry, fluorescence spectroscopy, and transmission electron microscopy (TEM) imaging techniques. The designed approach demonstrates outstanding linearity (20 to 2000 U L^-1 …

This study presents a novel and selective method for the determination of l-asparagine in diverse potato varieties under various storage conditions. L-asparagine levels serve as a crucial indicator for acrylamide formation, a hazardous substance in processed potato products. The fluorometric method utilized blue-emitting CDs (B-CDs), orange-emitting CDs (O-CDs), and the enzyme L-asparaginase for ratiometric detection of L-asparagine. Upon enzymatic hydrolysis of L-asparagine by L-asparaginase, liberated ammonia induced a pH increase in the reaction medium. This pH shift enhanced the fluorescence of B-CDs while simultaneously decreasing that of O-CDs, enabling sensitive and selective L-asparagine quantification. Comprehensive characterization of the CDs was performed using various spectroscopic techniques and transmission electron microscopy. The method demonstrated excellent sensitivity (LOD = 0.31 μM) and a wide linear range (1.0–50.0 μM). When the method was applied to potato samples, high recovery values (98.00–100.33 %) with low relative standard deviations (RSDs) were achieved, confirming the accuracy and precision of the method. The approach was employed to determine L-asparagine levels in three potato varieties (Lady Rosetta, Spunta, and Nicola) under different storage temperatures and durations. This method provides a valuable tool for monitoring L-asparagine content in potatoes, potentially aiding in the mitigation of acrylamide formation during processing. The robust performance and simplicity of the proposed technique make it suitable for routine analysis in both research and industrial applications within the potato industry.