DOAS (Differential Optical Absorption Spectroscopy) is a well-established technique for gas concentration measurements using the principle of ultraviolet (UV) absorption.  It is an optical system (non-contact measurement).  DOAS uses the unique ultraviolet (UV) absorption spectrum of Hydrogen Sulfide (H₂S) to make accurate quantitative analysis and calculate its concentration value.

Other gas detection modules using TDLAS (Tunable Diode Laser Absorption Spectrometry systems include:

• Handheld Methane (CH₄) Detector C10X
• Natural Gas (Methane & Ethane) Detector
• Mini Gas Flashlight Methane (CH₄) Detector L10M

These and other highly reliable and accurate Gas Detection Modules are available from Electro Optical Components (EOC).