Selected ion flow tube mass spectrometry (SIFT-MS) is a form of direct mass spectrometry that analyses volatile organic compounds (VOCs) in air with typical detection limits at parts-per-trillion level (by volume: pptv). Real-time, quantitative analysis is achieved by applying precisely controlled soft chemical ionization and eliminating sample preparation, pre-concentration and chromatography.
SIFT-MS uses ultra-soft, precisely controlled chemical ionization (CI) coupled with mass spectrometric detection to rapidly quantify VOCs and permanent gases to low part-per-trillion concentrations by volume (pptv).
Eight chemical ionization agents (reagent ions) are applied in Syft instruments: H3O+, NO+, O2+, O–, O2–, OH–, NO2–, and NO3–. These eight reagent ions react with analyte VOCs and inorganic gases in very well controlled ion-molecule reactions, but they do not react with the major components of air (N2, O2, and Ar).
This enables SIFT-MS to analyze air at trace and ultra-trace levels without preconcentration.
Rapid switching of eight reagent ions provides unsurpassed selectivity compared to other direct MS techniques.
Benefits of SIFT-MS:
SIFT-MS is an ideal tool for high- throughput and real-time gas analysis applications. Syft’s SIFT-MS instrumentation is industry proven, providing non-technical operators with laboratory-grade chemical analysis presented in a format that they can understand and act on.
This SIFT-MS Technology Overview Brochure equips technical readers with an understanding of the fundamentals of SIFT-MS and outlines the key benefits of Syft’s solutions.
There are three fundamental components of the SIFT-MS technique:
- Reagent ion generation and selection. The eight SIFT-MS reagent ions are formed by microwave discharge through moist or dry air at low pressure. One reagent ion is selected at any particular time using the first quadrupole mass filter.
- Analyte ionization. The selected reagent ion is injected into the flow tube and excess energy is removed through collisions with the carrier gas. The sample is then introduced at a known flow rate and the reactive compounds it contains are ionized by the reagent ion to form well-characterized product ions.
- Analyte detection and quantitation. Product ions and unreacted reagent ions are sampled into a second quadrupole mass spectrometer. Utilizing Syft’s compound library, the software instantaneously calculates each analyte’s absolute concentration.
SIFT-MS is unique: it provides repeatable, real-time quantitative analysis
Soft chemical ionization is applied very precisely in SIFT-MS, allowing it to provide unparalleled selectivity among direct mass spectrometry techniques.
The inherent technical characteristics (including the precise ionization control and elimination of the chromatographic column) has allowed Syft technologies to develop commercial instruments with significant usability and integration advantages compared to other direct mass spectrometry techniques and GC-MS.