On February 27, 2015, Stoll, Dwight R.; O’Neill, Kelly; Harmes, David C. published an article.Application of 99-60-5 The title of the article was Effects of pH mismatch between the two dimensions of reversed-phase × reversed-phase two-dimensional separations on second dimension separation quality for ionogenic compounds-I. Carboxylic acids. And the article contained the following:
Two persistent impediments to wider adoption of two-dimensional liquid chromatog. (2-dimensional-LC) are the perceptions that 2-dimensional methods are generally less sensitive than 1-dimensional ones, and that coupling of certain separation modes in a 2-dimensional system is difficult because of the neg. impact of the effluent of the 1st separation on the 2nd separation The authors address these problems in the specific case where reversed-phase separations were used in both dimensions of a 2-dimensional-LC system, but the pH is varied such that the ionization state of carboxylic acid analytes is different (i.e., neutral or neg. charged, in eluents buffered at pH 2 or 7) in the two columns. The authors 1st demonstrate that the effect of 1st dimension (1D) effluent on the performance of 2nd dimension (2D) separation of ionogenic solutes is much more serious than it is for neutral compounds where the pH of the eluent does not play a role in retention. The authors have systematically varied the properties of the sample solution injected into the 2D column (i.e., the 1D effluent), as well as the 2D eluent, with the goal of establishing guidelines for conditions that yield acceptable 2D performance. The organic solvent content of the 1D effluent and 2D eluent is not as important as the buffer concentrations in these two solutions, and the greater the ratio of buffer concentration in the 1D effluent relative to the 2D eluent, the smaller the volume one can inject into the 2D column before dramatic peak splitting occurs. The authors have then used the information from these simple experiments to guide both 1-dimensional experiments that mimic the 2D separation, and actual 2-dimensional separations, to demonstrate that online adjustment of the properties of the 1D effluent by dilution with a buffered solvent prior to injection into the 2D column is a very effective solution to the pH mismatch problem. When the buffer capacity of the diluent is high enough to effectively titrate the 1D effluent such that its pH approaches that of the 2D eluent, excellent 2D peak shape was obtained for the carboxylic acid analytes, even when the volume of injected sample solution exceeds the 2D column volume The experimental process involved the reaction of 2-Chloro-4-nitrobenzoic acid(cas: 99-60-5).Application of 99-60-5
The Article related to ph mismatch 2d reversed phase liquid chromatog, carboxylic acid second dimension separation 2d lc, carboxylic acids, detection sensitivity, solvent mismatch, two-dimensional, volume overload, ph effects and other aspects.Application of 99-60-5
Referemce:
Chloride – Wikipedia,
Chlorides – an overview | ScienceDirect Topics