Which of the following is a disadvantage of the IMS?

IMS disadvantages are false positives that delay transportation, compromise patient’s health and other negative issues when IMS is used for detection.

What is the advantage of an ion mobility separation step?

Mass separation The TOF-MS has many advantages including the high speed of data acquisition and good sensitivity. Since mass spectrum data is acquired on a microsecond time scale, multiple mass spectra are collected for each IMS spectrum (acquired on millisecond timescale).

What does ion mobility depend on?

The mobility depends not only upon the nature of the ion and gas but also upon the density of the gas, for the latter controls the mean free path of the ion. In atmospheric electricity, the mobilities of small and large ions weight their relative importance in atmospheric conduction.

What are the disadvantages of ion mobility spectrometry?

IMS is widely used in field portable chemical detectors due to its small size, portability, low power requirement, sensitivity, and quick analysis time (less than a few seconds in most cases). Disadvantages of IMS include relatively high cost, high false positive rate (i.e., low target specificity), and limited number of target chemicals.

Is there software for ion mobility mass spectrometry?

Ion mobility mass spectrometry is a rather recently popularized gas phase ion analysis technique. As such there is not a large software offering to display and analyze ion mobility mass spectrometric data, apart from the software packages that are shipped along with the instruments.

When was the ion mobility spectrometer first used?

IMS was introduced as an analytical tool by Cohen & Karasek (1970). In an ion mobility spectrometer, organic molecules are ionized and driven by an electric field against a counterflow of neutral drift gas. In their way to the detector, the ions collide multiple times with the drift gas, which reduce their speed.

How does gating work in ion mobility spectrometry?

In specified intervals, a sample of the ions is let into the drift chamber; the gating mechanism is based on a charged electrode working in a similar way as the control grid in triodes works for electrons.