US 8,247,784 B2 · Switched ferroelectric plasma ionizer

Abstract

A novel ion source for ambient mass spectrometry (switched ferroelectric plasma ionizer or “SwiFerr”), which utilizes the ambient pressure plasma resulting from a sample of barium titanate [001] whose polarization is switched by an audio frequency electric field. High yields of both anions and cations are produced by the source and detected using an ion trap mass spectrometer. Protonated amines and deprotonated volatile acid species, respectively, are detected in the observed mass spectra. Aerodynamic sampling is employed to analyze powders of drug tablets of loperamide and ibuprofen. A peak corresponding to the active pharmaceutical ingredient for each drug is observed in the mass spectra. Pyridine is detected at concentrations in the low part-per-million range in air. The low power consumption of the source is consistent with incorporation into field portable instrumentation for detection of hazardous materials and trace substances in a variety of different applications.

Claims23

Dependent claims

A switched ferroelectric plasma ionizer operable at ambient pressure, comprising:

a ferroelectric material having first and second surfaces on opposite sides thereof;
a grid electrode disposed adjacent to said first surface of said ferroelectric material, said grid electrode having a connection terminal configured to be connected to a first terminal of a voltage source;
a second electrode disposed adjacent to said second surface of said ferroelectric material, said second electrode having a connection terminal configured to be connected to a second terminal of a voltage source;
and
a housing disposed about said ferroelectric material, said grid electrode and said second electrode, said housing having an inlet port and an outlet port, said housing configured to contain at ambient pressure a volume of gas adjacent to said first surface of said ferroelectric material.

2 more elements

An ambient pressure gas analysis method, comprising the steps of:

exposing a gaseous sample of interest to a switched ferroelectric plasma ionizer operating at substantially ambient pressure, said switched ferroelectric plasma ionizer having a ferroelectric material having first and second surfaces on opposite sides of said ferroelectric material;
a grid electrode disposed adjacent to said first surface of said ferroelectric material, said grid electrode having a connection terminal configured to be connected to a first terminal of a voltage source;
a second electrode disposed adjacent to said second surface of said ferroelectric material, said second electrode having a connection terminal configured to be connected to a second terminal of a voltage source;
and a housing disposed about said ferroelectric material, said grid electrode and said second electrode, said housing having an inlet port and an outlet port, said housing configured to contain at substantially ambient pressure said gaseous sample of interest adjacent to said first surface of said ferroelectric material;
applying a ground potential to said grid electrode;
applying an alternating voltage of sufficient magnitude to satisfy the relationship |V/d|>Ec to said second electrode, where V is an amplitude of said applied alternating voltage relative to ground, d is a thickness of said ferroelectric material between said grid electrode and said second electrode, and Ec is a coercive field of said ferroelectric material;
analyzing an ionic species generated from said gaseous sample of interest to obtain a result;
and
performing at least one of recording said result, transmitting said result to a data handling system, or to displaying said result to a user.

6 more elements

Dependencies are inferred from the claim text.

Switched ferroelectric plasma ionizer

Life of this patent

Switched ferroelectric plasma ionizer

Life of this patent

Abstract

Claims23