Fitting to the temperatures, let’s have a look at the separation of “heat stable salts”. This term originates from acid gas removal processes used in the petrochemical industry in which amines remove acidic gases like H2S and CO2. Anionic contaminations present in the petrochemical product, however, can also form salts, which cannot be regenerated by the addition of heat, hence the “heat stable salts”. Due to the problems, they could cause in the process (corrosion, unscheduled outages), they need to be determined, and IC is the method of choice. AN 72622 details the RFIC approach Manali and Jeff used. Very interesting: The use of the Thermo Scientific Dionex AS25A! It is a unique variant of the Dionex IonPac AS25, with optimized selectivity towards bromide and nitrate while maintaining its capability to separate anionic sulfur species in complex matrices. Please find its part number in this application note.
High temperature is also prerequisite for the determination of total fluorine, chlorine, and sulfur in aromatic hydrocarbons, like gasoline. For this application, the combination of a combustion unit and an IC instrument proves helpful – aka Combustion IC (CIC). The organic matrix is oxidized to CO2 and water, with the acidic combustion products (HF, HCl, H2SO4) being absorbed in an aqueous solution. This solution is then automatically injected onto an anion exchange column, where the analytes are separated using RFIC conditions on a Dionex IonPac AS18.
The CIC method described in AN 72693 is based on ASTM Method D7359-14a, and shows good linearity and precision and accurately quantifies amounts of anions present in the sample.
While you and I are familiar with IC, from time to time, I’d like to have some additional background information on MS. And that is the reason, why I would like to share a White Paper published by our colleague Debadeep Bhattacharyya talking about triple-quadrupole MS and Orbitrap-HRAMS, their similarities, differences, and capabilities. I truly enjoyed reading, and hope you will find it as nicely written, and informative as I did.
Dr. Detlef Jensen
EU Sales Support Expert for
Ion Chromatography and Environmental Market