Analysis of herbicides on a single C30 bead via a microfluidic device combined with electrospray ionization quadrupole time-of-flight mass spectrometer

An integrated system combining microfluidic device with electrospray ionization quadrupole time-of-flight mass spectrometer (ESI-Q-TOF-MS) was developed for detecting a series of herbicides on a single C30 bead. We presented single C30 beads manipulation which had absorbed sequential herbicides, based on the precise control of the concentration and absorption time. The simple microchip consisting of a straight channel and a hole in the middle enabled single C30 bead introduction, transformation and location. ESI-Q-TOF-MS was employed to realize highly sensitive qualitative analysis and implement semi-quantitative analysis. Once the C30 bead contacted with eluting solution, the solute transferred into eluting and would be detected by ESI-Q-TOF-MS. Depending on desorption curves obtained, accurate and clear characteristic peaks for each analysts were carried out. Our investigations on single-particle analysis showed that the combination of microfluidic device and mass spectrum could reduce the analysis time to 5 min and the solvent consumption to 2.5 μL, realize high sensitivity detection, and avoid the complex sample pretreatment. The significant potential on analysis of environmental samples on this combination system by single particle was demonstrated.