Siloxanes are silicone-based compounds characterised by a chain of alternating silicon (Si) and Oxygen (O2) atoms. They are used for their softening, smoothing, and moistening action. They make products like deodorants slide on more easily, and leave hair and skin more soft and silky.

Siloxanes are in products that contain silicon such as silicone baking utensils and pans, baby nipples, and pacifiers, medical devices and implants, water-repellent windshield coating, construction lubricants and sealants as well as deodorant creams and moisturizers and shampoos.

sampling siloxanes in a gas stream will usually be done using GC-MS and FT-IR and is usually completed by taking gas bag samples to analysed in the laboratory. The STS siloxane monitor however is an in-field instrument that takes the sample directly from the gas stream and utilises a unique GC-NIR detection system to produce rapid measurements.

In field measurement of siloxanes is possible given the correct instrument and the right sample handling- consideration must be given to the propensity for siloxanes to drop out into condensates and equally to stick to cold surfaces, careful sample handling is therefore essential to obtain an accurate result. On site instruments need also to be robust and able to withstand the contamination in the gas stream presented by numerous other compounds that can influence the true result. STS mitigates this issue by using a bespoke GC column to separate and concentrate the siloxanes prior to measurement in an IR chamber.

L2 is the smallest of the linear siloxane molecules and the hardest to effectively trap and measure. Selection of both the right media in a Gas Chromatography column and the correct detector are essential to effect an accurate result. Careful thermal management and timing of the release from the column must be made to ensure that the molecules are not lost before measurement. The new STS Siloxane Monitor V4.0 enables this capture and measurement outputting the result as a total Siloxane value in mg/m3.