Method and apparatus for contained-electrospray for use in mass spectrometry and droplet reactions

#There is an increasing need for better sensitivity of electrospray ionization (ESI) to accurately quantify different types of analytes in complex mixtures. However, quantitative analyses of mixtures by ESI-MS is often complicated by differences in ionization response for different compounds (e.g., among polar, non-polar, and ammonium cations). There are often significant suppression effects among the analytes and the resultant mass spectrum from such a mixture displays only surface active analytes. The apparatuses, systems, and methods discussed herein address these and other needs.

#Discussed herein are apparatuses that can comprise an electrospray emitter comprising a sample capillary extending from a sample inlet to a sample outlet; and a voltage source conductively coupled to the sample capillary and configured to apply a voltage to the sample capillary. In some examples, the voltage applied to the sample capillary can be from 4 kV to 5 kV. In some examples, the sample capillary can be formed from fused silica.

#The apparatus can further comprise an element comprising a conduit coaxially disposed around the electrospray emitter thereby forming a chamber extending between the conduit and the sample capillary and terminating in a gas outlet. In some examples, the conduit can be formed from fused silica.

#FIG. 1 is a schematic representation of an example apparatus in the extended position.

#FIG. 2 is a schematic representation of an example apparatus in the retracted position.

#FIG. 3 is a schematic representation of the experimental apparatus for the contained electrospray (ES) process using type II operational set-up.

#Mass spectrometry (MS) has emerged as an important analytical tool, and continues to show potential in many fields not only because of its specificity and sensitivity in chemical analysis but also because it can be used as a tool for studying chemical reactions. One of the focuses of analytical mass spectrometry is molecular structural characterization. Traditionally, this has been achieved in three steps: (1) ion generation, (2) precursor ion selection, and (3) fragmentation or reaction of mass-selected precursor ions with specific neutral reagents under the high vacuum environment. A more recent set of MS techniques have been developed in which ion generation and reaction occur simultaneously in a single stage MS experiment. These techniques (e.g., reactive desorption electrospray ionization) have typically been used to enhance the detection (and sometimes imaging) of analytes with low proton affinities, and for the studies of reaction intermediates.

#More recently still, has been the use of MS as a tool for studying chemical changes is the ability to generate intact molecular ions, focus and use them as ordinary reagents for organic reactions at ambient surface, outside the mass spectrometer.

#Apparatuses