Development of an Open Droplet Microchannel-Based Magnetosensor for Immunofluorometric Assay of Trimethoprim in Chicken and Pork Samples with a Wide Linear Range.

Trimethoprim (TMP), functioning as a synergistic antibacterial agent, is utilized in diagnosing and treating diseases affecting livestock and poultry. Human consumption of the medication indirectly may lead to its drug accumulation in the body and increase drug resistance due to its prolonged metabolic duration in livestock and poultry, presenting significant health hazards. Most reported immunoassay techniques, such as ELISA and immunochromatographic assay (ICA), find it challenging to achieve the dual advantages of high sensitivity, simplicity of operation, and a wide detection range. Consequently, an open droplet microchannel-based magnetosensor for immunofluorometric assay (OMM-IFA) of trimethoprim was created, featuring a gel imager to provide a signal output derived from the highly specific antibody (Ab) targeting trimethoprim. The method exhibited high sensitivity in chicken and pork samples, with LODs of 0.300 and 0.017 ng/mL, respectively, and a wide linear range, covering trimethoprim's total maximum residue limits (MRLs). Additionally, the spiked recoveries in chicken and pork specimens varied between 81.6% and 107.9%, maintaining an acceptable variation coefficient below 15%, aligning well with the findings from the ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) technique. The developed method achieved a much wider linear range of about 5 orders of magnitude of 10-2-103 levels with grayscale signals as the output signal, which exhibited high sensitivity, excellent applicability and simple operability based on magnetic automation.

Component analysis using UPLC-Q-Exactive Orbitrap-HRMS and quality control of Kudingcha (Ligustrum robustum (Roxb.) Blume).

Although Kudingcha (Ligustrum robustum (Roxb.) Blume) has been widely used as both traditional medicine and food, systematic studies on their basic active components and quality control are lacking. In this study, a rapid method of identifying the general chemical components of Ligustrum robustum (Roxb.) Blume was established for the first time using UPLC-Q-Exactive Orbitrap-HRMS, and its major basic components were specified as phenylpropanoid, monoterpene, and flavonoid glycosides. The characteristic cleavage pathways of the phenylpropanoid, monoterpene, and flavonoid glycosides were further investigated and elaborated, which could assist in identifying the structures of similar components of other Chinese herbal medicines. A breakthrough was achieved in establishing a chemical fingerprinting profile of Ligustrum robustum (Roxb.) Blume from its original growing areas in China, and chemometric measures were applied to investigate the causes for the variations in its quality stability. The results indicated significant differences in the characteristic compositions of phenylpropanoid and monoterpene glycosides between mature and young leaves of Ligustrum robustum (Roxb.) Blume; however, no significant variation was observed owing to different production areas. Graded harvesting criteria should be established, and harvest period should be specified according to the target active components while considering agricultural metrics, such as leaf shape index, leaf length, and leaf width, to ensure the consistency in quality of active components during their production. From the perspective of overall quality control, an unprecedented quantitative analysis of multi-components by single marker was set up to analyze the signature components of phenylpropanoid glycosides (acteoside, isoacteoside, ligurobustoside N, and ligupurpuroside B) to increase the analytical efficiency and reduce research costs. This study created a scientific basis for the standardized operation, elucidation of the pharmacological materials, and quality control of food and supplements production with Ligustrum robustum (Roxb.) Blume as a raw material.