Renault SA: equity research

UNL - NSB

Renault SA: a shifting industry

UNL - NSB

Active modulation in neat carbon dioxide packed column comprehensive two-dimensional supercritical fluid chromatography

After demonstrating in a first paper the feasibility of SFCxSFC without decompression of the mobile phase, a modified interface has been developed in order to perform active modulation between the two SFC dimensions. In this paper, it is shown that the new interface enabled independent control of modulation parameters in SFCxSFC and performed a band compression effect of solutes between the two SFC dimensions. The effectiveness of this new modulation process was studied using a Design of Experiments. The SFCxSFC prototype was applied to the analysis of a real oil sample to demonstrate the benefits of the active modulator; in comparison to our previous results obtained without active modulation, better separation was obtained with the new interface owing to the peak compression occurring in the modulator

Construction of a new interface for comprehensive supercritical fluid chromatography x reversed phase liquid chromatography (SFC x RPLC)

The design of a new interface to hyphen high efficiency supercritical fluid chromatography (SFC) and fast RPLC in a comprehensive configuration is described. SFC x RPLC is a viable alternative to normal phase (NP) LC x RPLC and is characterized by high orthogonality. Compared to NPLC x RPLC an additional advantage is the expansion of supercritical carbon dioxide (CO2) when exposed to atmospheric pressure leading to fractions consisting of solvents that are miscible with the second dimension RPLC mobile phase. The interface consists of a two-position/ten-port switching valve equipped with two packed octadecyl silica (C-18) loops for effective trapping and focusing of the analytes after elution from the SFC dimension. The addition of a water make-up flow to the SFC effluent prior to entering the loops is of fundamental importance to efficiently focus the solutes on the C-18 material and to reduce interferences of expanded CO2 gas on the second dimension separation. The features of the system are illustrated with the analysis of a lemon oil sample