Construction of a Highly Selective Enrichment, Ionization, and Detection Platform Based on a Broad-Spectrum Antibody

Ambient mass spectrometry (AMS) allows direct analysis of various raw food samples with minimal or no sample pretreatment, but the trace analytes in complex food samples still have problems with limitations. In this work, we developed a platform based on coated stainless steel sheet spray mass spectrometry for fast, in situ, high-throughput, and high selectivity multiresidue analysis of fluoroquinolone drugs (FQs). The sensitivity of the platform was enhanced via coupling broad-spectrum antibodies against FQs to graphene oxide coated blade spray (CBS)-MS through a streptavidin-biotin (SA-biotin) interaction. The prepared platform had sufficient loading capacity for SA (1.37 mg/piece) and the antibody (84.8 μg/piece), which is greater than that of physical mixing and the EDC/NHS covalent coupling strategy. With simplified sample pretreatment, this platform demonstrated comparable sensitivity to high performance liquid chromatography-mass spectrometry (HPLC-MS/MS) (0.08-0.16 ng/mL in phosphate-buffered saline and 0.21-0.32 ng/mL in diluted milk). Meanwhile, compared with HPLC-MS/MS, the method is rapid (enrichment: 10 min, detection: <1 min) and acceptable recoveries (81.94-102.08%) can be obtained. The presence of analytes can be monitored by MS/MS spectra, and multiple analytes can be measured simultaneously in a single assay. This study is expected to provide a powerful and portable tool for rapid laboratory analysis and reliable screening in the field.