In this paper, a separation procedure combining molecularly imprinted-solid phase extraction (MI-SPE) was developed for the isolation of melamine. The molecularly imprinted polymer (MIP) was prepared using precipitation polymerization method where melamine as template, 9-vinylcarbazole as functional monomer, ethtylene glycol dimethacrylate as a cross-linker and benzoyl peroxide as initiator. An off-line MI-SPE method followed by ultra-performance liquid chromatography detection of melamine was established. MIP showed a better affinity toward melamine compared to non imprinted polymer (NIP) with a maximum binding capacity of 53.01 mg/g MIP. Based on the correlation coefficients, the kinetic study indicated that the adsorption of melamine by MIP fit a pseudo-second order model. From isotherm study, adsorption of melamine by MIP increased when the concentration of melamine increased and followed a Freundlich isotherm model, which indicates the sorption can be described by multilayer sorption. The interference study proved that MIP has better binding capacity towards melamine if compared to NIP due to specific sites of melamine occurred in MIP particles.

In this study, an electrochemical immunosensor was introduced for the detection of tuberculosis (TB) via utilization of a modified electrode containing a quantum dot (CdSe/ZnS QD) and functionalized silica nanoparticles (SiNPs) on screen-printed carbon electrode (SPCE) CdSe/ZnS QD/SiNPs/SPCE, by employing indirect enzyme-linked immunosorbent assay (ELISA). Here, the fabricated electrode was linked to the biocatalytic action of enzyme catalase through antigen–antibody binding for the detection of the antigen (CFP10–ESAT6) by means of producing a differential pulse voltammetry (DPV) current. The characterization and cyclic voltammetry (CV) of the modified electrode showed good electrochemical behavior and enhanced high electron transfer between the electrode and analyte. Moreover, the active surface area was 4.14-fold higher than the bare SPCE. The developed method showed high selectivity towards CFP10–ESAT6 compared with the other TB proteins. The detection of CFP10–ESAT6 also showed a linear response towards different concentrations of CFP10–ESAT6 with R² = 0.9937, yielding a limit of detection (LOD) of as low as 1.5 × 10⁻¹⁰ g/mL for a linear range of 40 to 100 ng/mL of CFP10–ESAT6 concentration. The proposed method showed good reproducibility of target analyte with a relative standard deviation of 1.45%.

The widespread use of whey protein supplements raises concerns about contamination with banned diuretics, posing health risks and the potential for inadvertent doping. In this study, a liquid–liquid extraction (LLE) procedure coupled with liquid chromatography–tandem mass spectrometry (LC–MS/MS) was developed and validated for the simultaneous detection of 23 diuretics in whey protein supplements. The method was assessed for selectivity, linearity, matrix effect, recovery, precision, and sensitivity. Statistical evaluation using the Shapiro-Wilk and Levene’s tests confirmed that most calibration residuals exhibited a normal distribution and homogeneity of variance, ensuring the reliability of the regression model. The method demonstrated excellent linearity (R² = 0.980–0.999) and low method detection limits (MDLs, 0.39–2.73 ng/g). A total of 58 commercially available whey protein supplements were analysed, and bendroflumethiazide (D4) was detected in 12 samples, with concentrations ranging from 1.4 to 40.4 ng/g. These findings highlight the applicability of the validated method for routine monitoring and underscore the urgent need for stringent quality control and regulatory oversight in the sports supplement industry to protect consumer health and maintain fair competition.