- Analytical methods
- Gas chromatography
- Liquid chromatography
- Infrared spectroscopy
- Other spectroscopy
- Inductively coupled plasma
- Mass spectrometry
- Nuclear magnetic resonance
- Other methods
- Supercritical fluid
Chemiluminescence, like atomic emission spectroscopy (AES), uses quantitative measurements of the optical emission from excited chemical species to determine analyte concentration. However, unlike AES, chemiluminescence is usually emission from energized molecules instead of simply excited atoms. Taking total sulfur content measurement using chemiluminescence as an example, the instruments use a two stage method where the sample is first pyrolised in a flame of purified, or HiQ Synthetic air 5.0 and HiQ Hydrogen 5.0 under vacuum to generate sulfur monoxide which is then transported by a carrier gas, typically HiQ Argon 5.0 or HiQ Nitrogen 5.0 at a purity of 99.999% to a chamber where it reacts with ozone to generate sulfur dioxide and UV light. The light generated is measured by a photomultiplier tube to measure the total quantity of sulfur in the sample. A quartz furnace, fed with HiQ synthetic air 5.0, or HiQ oxygen 4.8, is an alternative pyrolysis technique suitable for sample preparation in this instrumentation setup. However, unlike AES, chemiluminescence is usually emission from energised molecules instead of simply excited atoms. Chemiluminescence can take place in either the solution or gas phase and is used for quantitative determination of many important inorganic and organic species in trace amounts.
Gas generator recommendation
|≤ 100 ppb||BASELINE C106 series||n/a|
|≤ 100 ppb||HiQ Nitrogen 5.0||BASELINE C106 series||HiQ MISTRAL Nitrogen|
|≤ 100 ppb||HiQ Air 4.0||BASELINE C106 series||HiQ Zero Air|
|≤ 100 ppb||HiQ Nitrogen 4.6||BASELINE C106 series||HiQ MISTRAL Nitrogen|
|≤ 100 ppb||HiQ Argon 4.8||BASELINE C106 series||n/a|
Chemiluminescence is produced when a chemical reaction yields an electronically excited species, which emits light as it returns to its ground state. The excited particle can be the product of a reaction between the analyte and a suitable reagent e.g., ozone or hydrogen peroxide. In other cases the analyte is not directly involved in the chemiluminescence reaction; instead it is the inhibiting effect of the analyte that serves as the analytical parameter.
Chemiluminesence Spectrometry - Instrumentation
The instrumentation for chemiluminescence measurements is simple and can consist of only a suitable reaction vessel and a photomultiplier tube.
Chemiluminesence Spectrometry - Analysis of gases
Atmospheric pollutants such as ozone, oxides of nitrogen and sulphur compounds can be determined with chemiluminescence methods. The most widely used of these methods is for the determination of nitrogen monoxide. Ozone from an electrogenerator and the atmospheric sample are drawn continuously into a reaction vessel and the radiation is then monitored by a photomultiplier tube. The reaction of nitrogen monoxide with ozone has also been applied to the determination of the nitrogen dioxide content of automobile exhaust gas. Other important chemiluminescence methods are used for monitoring atmospheric ozone and determination of sulphur-containing air pollutants such as sulphur dioxide and hydrogen sulphide.