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 shall be 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 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.
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, e.g.
Gas Chromatograph - Ion Mobility Spectrometer (GC-IMS) of G.A.S. combines the
high selectivity of a Gas Chromatograph with the extraordinary sensitivity of
an IMS (typically low ppbv range)
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