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Toxic industrial chemicals (TICs) or materials (TIMs) are substances that exhibit harmful effects on humans but are commonly used at industrial sites, in manufacturing facilities and pharmaceutical chemical plants.

With its GC-IMS device G.A.S. developed a highly selective and sensitive measuring system for rapid monitoring of dimethyl sulfate (DMSO4), toluene diisocyanate (TDI) and trans-4-methyl cyclohexyl isocyanate (4-MCI) in industrial areas. The instrument continuously samples the ambient air, which is monitored. The run time could be decreased to a value of 2 min including a GC separation to avoid matrix effects and also including a cleaning step of the instrument’s gas touching parts by passing clean gas through in order to avoid carry-over. The measurement devices were calibrated for monitoring of DMSO4 and isocyanate species down to the low ppbv range depending on customers needs.

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Dimethyl Sulfate

Dimethyl sulfate (DMSO4) is commonly used as a reagent for the methylation of phenoles, amines, and thiols. In industry DMSO4 is preferred, compared to other methylating agents, because of its low cost and high reactivity. It is known that DMSO4 is carcinogenic, mutagenic, highly poisonous, corrosive, environmentally hazardous and volatile. The substance can be absorbed through skin, mucous membranes, and gastrointestinal tract.


Due to their electrophilic properties, isocyanates are reactive towards many nucleophilic substances like alcohols, amines or even water. Several isocyanates are extremely poisoning and exposure can result in lung edema, emphysema, hemorrhages, bronchial pneumonia and death.

Other Compounds

G.A.S. develops monitoring devices for a variety of toxic, harmful or dangerous substances, such as benzene, toluene, xylene isomers, acrolein or acetaldehyde, just to name a few. For further information and requests, please contact us at

Monitoring of Odorants in Natural Gas

The gas odour level of natural gas needs to be monitored at regular intervals to secure the required level of the organosulphur compounds tetra-hydro-thiophene (THT) and tert-butyl-mercaptane (TBM) or the sulfur-free (Gasodor®-S-Free®) markers which are used worldwide to odorize natural gas. The safety concern is to assure a minimum concentration of the alarming smell while not overdosing the high-priced odour markers.

Odorant natural gasWith experience of more than 10 years in the natural gas application G.A.S. in 2015 launched a new customized instrument generation. Compared to former products the GC-IMS-ODOR is based on gas chromatography which enables an excellent separation of any natural gas matrix and to measure any odorant with an accuracy of better than +/- 1 mg/m3. Moreover the configuration, workflow and particularly its user-interface are optimized to correspond to the daily routines and operations of utility personnel in the field.

The GC-IMS-ODOR is versatile as its 19" housing allows a portable on-site use with an automatic pressure independent flow adjustment, one-klick operation and a measurement time of 4 minutes. Results are stored on the compact flash card, can be linked to locations and later being downloaded using a USB stick to be printed as report or converted to Excell tables.

The GC-IMS-ODOR can alternatively be operated as on-line monitoring device where it samples and fully automatic re-calibrates itself at user defined intervals. Data can be transfered via Ethernet or 4-20mA output to a control room. Using this operation mode and positioning the instrument at critical 'end-points' of its grid the utility assures a 24/7 control of its odour concentration and can react immediately in case of a problem at the point of odorization, the grid or an empty odorant container.

Therefore the GC-IMS-ODOR represents a rugged, value for money high-end equipment that can still be operated by the technical personnel of natural gas utility.