Electrostatic field–induced tip‐electrospray ionization mass spectrometry for direct analysis of raw food materials

Abstract

Rapid characterization of metabolites and risk compounds such as chemical residues and natural toxins in raw food materials such as vegetables, meats, and edible living plants and animals plays an important part in ensuing food quality and safety. To rapidly characterize the analytes in raw food materials, it is essential to develop in situ method for directly analyzing raw food materials. In this work, raw food materials including biological tissues and living samples were placed between an electrode and mass spectrometric (MS) inlet under a strong electrostatic field; analytes were rapidly induced to generate electrospray ionization (ESI) from the sample tip by adding a drop of solvent onto the sample. Therefore, the electrostatic field–induced tip‐ESI‐MS allows raw samples to avoid contacting high voltage, and thus this method has the advantage for in vivo analysis of food living plants and animals. Metabolite profiling, residues of pesticides and veterinary drugs, and natural toxins from raw food materials have been successfully detected. The analytical performances, including the linear ranges, sensitivity, and reproducibility, were investigated for direct sample analysis. The ionization mechanism of electrostatic field–induced tip‐ESI was also discussed in this work.

Investigating distributions and changes of alkaloids in living Catharanthus roseus under low‐phosphorus stress using wooden‐tip electrospray ionisation mass spectrometry

“…Figure 3(H) shows peaks at m/z 337 and m/z 457 in the MS/MS spectrum of AVBL ( m/z 793), clearly showing that AVBL was formed by CAT ( m/z 337) and VIN ( m/z 457) in C. roseus . Since CAT and VIN are separated at different cells, it was hypothesised that when the plant is wounded such as in vivo sampling with wooden tip in this work, CAT and VIN are rapidly brought together to allow formation of AVBL under enzyme effect in living C. roseus 6,26 …”

Recent Advances of In‐Source Electrochemical Mass Spectrometry

“…It should also be noted that the in-source electrochemical property is not always wanted. Methods of alleviating or avoiding electrochemistry in ion sources include fast polarity switching" [110] flow splitting, [111] and inductive [112][113][114] and extractive ESI. [115] With further instrumentation development in the future, our expectations include i) EC-MS with ultra-low delay time to probe transient species with half-lives of pico-to nanoseconds; ii) rapid and high-throughput screening of electrochemical reactions and condition optimization to guide electrosynthesis; iii) increasing studies on electroreduction and extensive applications to hardly ionizable compounds.…”

“…It should also be noted that the in‐source electrochemical property is not always wanted. Methods of alleviating or avoiding electrochemistry in ion sources include fast polarity switching„ [110] flow splitting, [111] and inductive [112–114] and extractive ESI [115] …”

Contactless electrospray ionization mass spectrometry for direct detection of analytes in living organisms

“…[12][13][14] Under HV-contactless mode, analytes were induced to form spray ionization by applying a drop of solvent onto the substrate under an electric field. [12][13][14][15] The attractive feature of contactless ESI is that the raw samples could be directly ionized without connecting HV cable. 16 However, there are a few applications in vivo analysis of living organisms using this contactless ESI-MS method.…”