Quinones are becoming an essential tool for refractory organics treatment, while their quantification may be not well-considered. In this paper, two kinds of potential errors in quantification were evaluated in multiple pH conditions. They were derived from the coexistence of oxidized/reduced quinone species (Type I) and pH-sensitive feature (Type II), respectively. These errors would remarkably influence the accuracy of quantification while they haven't been emphasized. Thus, to elaborate the relationship between the two types of errors and the absorbance or pH conditions, three typical quinones [Anthraquinone-1-sulfonate (α-AQS), anthraquinone-2,6-disulfonate (AQDS) and lawsone] were selected and their acid dissociation coefficients (p K a) as well as UV–Vis spectra were determined. Results revealed that, for Type I, the relative error (RE) of α-AQS concentration would exceed the limit (5%) when reduced α-AQS was below 48% of total α-AQS. Similar results were found for lawsone. However, the RE can be eliminated by the equation established in this paper. For Type II, the pH-sensitive feature was related to the p K a values of quinones. Absorbances of α-AQS and lawsone would change remarkably with pH variation. Therefore, a model for correction was established. Analog data showed high consistency with experimental data [ r = 0.995 ( n = 25, p < 0.01) and r = 0.997 ( n = 36, p < 0.01), for lawsone and α-AQS respectively]. Especially, the determination of AQDS concentrations was noticed to be pH-independent at 437 nm under pH 4.00 to 9.18 conditions. Based on these features, a comprehensive data solution was proposed for handling these errors.
In this study, a highly efficient magnetic molecularly imprinted polymer nanocomposite material was prepared using multi-walled carbon nanotubes as carriers. The characterization of the obtained nanocomposite material was conducted using Fourier transform infrared spectroscopy, a vibrating sample magnetometer, a thermogravimetric analyzer, a scanning electron microscope, and a transmission electron microscope. The adsorption properties of the nanocomposite material were evaluated through adsorption experiments, including static adsorption, dynamic adsorption, and selective recognition studies. The prepared nanocomposite material, serving as a selective adsorbent, was applied in magnetic solid-phase extraction. Subsequently, the derivatized samples were analyzed for glucose in fish serum using liquid chromatography–tandem mass spectrometry. Under optimal conditions, the detection limit was 0.30 ng/mL, the quantitation limit was 0.99 ng/mL, satisfactory spiked recovery rates were obtained, and the relative standard deviation was less than 1.1%. Using 2-deoxy-D-ribose as the template molecule and a structural analog of glucose allowed us to eliminate the potential template leakage in qualitative and quantitative analyses, effectively avoiding the issues of false positives and potential quantitative errors, compared to traditional methods. A method for detecting glucose levels in fish serum based on molecularly imprinted polymer technology has been successfully developed to determine the stress and health levels of fish.