HLB-MCX-Based Solid-Phase Extraction Combined with Liquid Chromatography–Tandem Mass Spectrometry for the Simultaneous Determination of Four Agricultural Antibiotics (Kasugamycin, Validamycin A, Ningnanmycin, and Polyoxin B) Residues in Plant-Origin Foods

Abstract

An ultrahigh-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method was established for the determination of four highly polar agricultural antibiotics kasugamycin, validamycin A, ningnanmycin, and polyoxin B in plant-derived foods. The samples were extracted with a 0.2% formic acid solution, purified by hydrophilic–lipophilic balance and mixed-mode cation-exchange solid-phase extraction, and then reconstituted for UPLC–MS/MS detection. The chromatographic analysis was performed on a BEH Amide column (100 mm × 2.1 mm, 1.7 μm) using gradient elution with a 0.1% formic acid solution and 0.1% formic acid acetonitrile as mobile phases. Method validation was performed on 15 matrices spiked at 0.02 (or 0.05), 0.5, and 2 mg/kg. The mean recovery rate ranged from 75 to 102% with relative standard deviations (RSD) was less than 20%. Good linearities (r > 0.99) in the range of 0.002–0.2 μg/mL were obtained. The limits of quantification (LOQs) were 0.02 and 0.05 mg/kg. Studies on the stability of the analytes in the stored kiwifruit samples showed that kasugamycin, validamycin A, and ningnanmycin were stable for at least 6 months, while polyoxin B was observed to be partially degraded (the degradation rate at 6 months was 31.3%). The method was demonstrated to be effective and reliable in real samples. In the kiwifruit samples treated after 7 days, no residues of ningnanmycin and polyoxin B were detected, while the residues of kasugamycin and validamycin A were 0.12 and 0.038 mg/kg, respectively.

Development of an Analytical Method for Kasugamycin Residue in Herbal Medicine, <i>Achyranthes japonica</i> Nakai

“…Nevertheless, it was reported that the retention time and sensitivity were excellent, and because of confirming this, sufficient retention time and sensitivity were secured, as shown in Fig. 1(c) [7,10,19]. Therefore, in this study, an amide column highly effective for kasugamycin was selected and analyzed.…”

“…Water was selected as the final extraction solvent in% with the highest recovery rate (Table S1). The extraction of kasugamycin from dried samples using methanol and water was previously reported, and the recovery rate found increased as the water content increased [7]. Therefore, in this study, 10 mL of distilled water was added to the sample (5 g), followed by a wetting process for 1 h, and then extracted with 40 mL of water adjusted to pH 4.5-5 by adding 0.1% formic acid solution.…”

“…1(b) [20][21]. An amide column is a form in which polar amide groups are bound [7]. Nevertheless, it was reported that the retention time and sensitivity were excellent, and because of confirming this, sufficient retention time and sensitivity were secured, as shown in Fig.…”

“…Moreover, kasugamycin is nonvolatile and is physically and chemically unstable in heat; thus, its analysis process is difficult due to its low sensitivity during analysis [5]. According to previous studies, biological potency assays (cup, standard strain Pseudomonas fluorescens) and capillary electrophoresis (CE) were performed, but there were disadvantages in that the analysis time was long, and there were poor precision and selectivity [7]. Also, in the case of HPLC and GLC, which are often used for residual analysis, HPLC/UV showed low absorbance because there was no chromophore for ultraviolet or fluorescence, so there was a sensitivity problem.…”

“…Several reports confirmed using various SPE methods to remove interfering substances from samples and improve the sensitivity of kasugamycin. Many authors reported the purification of peppers and soil extracts using an MCX SPE cartridge [7,10]. A study of simultaneous analysis of agricultural fungicides using an HLB SPE cartridge and MCX SPE cartridge was reported.…”