ELECTROSPRAY AND NANOSPRAY IONIZATION OF DISCRETE SAMPLES IN DROPLET FORMAT

摘要

H: /SVM/Interwoven/NRPortbl/DCC/SVM/7011846_1.docx-25/11/2014 Droplets or plugs within multiphase microfluidic systems have rapidly gained interest as a way to manipulate samples and chemical reactions on the femtoliter to microliter scale. Chemical analysis of the plugs remains a challenge. It has been discovered that nanoliter plugs of sample separated by air or oil can be analyzed by electropstray ionization mass spectrometry when pumped directly into a fused silica nanospray emitter nozzle. Using leu-enkephalin in methanol and 1% acetic acid in water (50:50 v:v) as a model sample, we found carry-over between plugs was < 0.1% and relative standard deviation of signal for a series of plugs was 3%. Detection limits were 1 nM. Sample analysis rates of 0.8 Hz were achieved by pumping 13 nL samples separated by 3 mm long air gaps in a 75 pm inner diameter tube. Analysis rates were limited by the scan time of the ion trap mass spectrometer. The system provides a robust, rapid, and information-rich method for chemical analysis of sample in segmented flow systems. WO 2010/148339 PCT/IUS2010/039233 Figure 1 (a) Connection Tube Pump Fluidic Coupling Union: (Could be integral to pump) Displacement or Pressure Pump (Gas or Liquid) May have flow and pressure sensors 1-D segmented sample array Array Device: for Storage/Transfer/Transport/Delivery Vessel, Tube, etc Fluidic Coupling Union (Could be integral to Array Device) Spray Emitter Nozzle, Electrically Conductive: DC (or AC) Power Su apply Tube, Chip, Coated Tube, etc. 1,000-5000 V Ty pical Could be integral with Array Device &~Electrical Contact with VSample plug being sprayed Electrospray Plume Spray Receiver: Mass Spectrometer Inlet, Substrate, Array Plate, Well Plate etc.