Three versus five micrometer chlorinated polysaccharide‐based packings in chiral capillary electrochromatography: performance evaluation

Abstract

In this study, a test set of 44 nonacidic compounds was analyzed on four 3 µm chlorinated polysaccharide-based chiral stationary phases with cellulose tris (3-chloro-4-methylphenylcarbamate) (Lux Cellulose-2®; LC2), amylose tris (5-chloro-2-methylphenylcarbamate) (Lux Amylose-2®, LA2), cellulose tris (4-chloro-3-methylphenylcarbamate) (Lux Cellulose-4®; LC4) and cellulose tris (3,5-dichlorophenylcarbamate) (Sepapak-5®, Sp5) as selectors. The analysis times, retention factors, efficiencies and enantioselectivities were compared with the results obtained on their 5 µm analogs. All 3 µm packings, except for LA2, individually separated more compounds than their 5 µm analogs. When the cumulative success rates on the 3 and 5 µm packings were considered, it was observed that they were similar for both particle sizes; the combination of three or four 5 µm columns separated one compound more from the considered test set than that of the same number of 3 µm columns. Furthermore, it was observed that the 3 and 5 µm packings showed some complementarity. Only four compounds were not separated on any of the columns, while the use of only either the 3 or 5 µm columns resulted in 10 and nine not-separated compounds, respectively. The analyses on 5 µm LC2 and Sp5 were faster than on their 3 µm analogs. For LC4 the 3 µm packing showed the shortest analysis times and diverse analysis times for both particle sizes were obtained on LA2. Furthermore, three out of four 3 µm packings, that is, LC2, LC4, and Sp5, were found to be more efficient than their 5 µm analogs.

Enantiomers separation by capillary electrochromatography using polysaccharide‐based stationary phases

“…Even though a loss in the efficiency was observed when the particle diameter was enlarged in the range of 5–7 μm , only a slight difference was observed when 3 and 5 μm particles were compared, as also reported in the conclusions by Hendrickx et al. . However, as expected, the EOF was strongly diminished when using 12 μm particles.…”

“…Vander Heyden and his research group have developed separation strategies based on the large‐scale screening of racemic mixtures generally in pharmaceutical products using polysaccharide derivatives based CSPs . In this regard, basic, neutral, and bifunctional pharmaceutical compounds were selected and tested in order to verify the enantiorecognition capabilities of chlorinated and nonchlorinated CSPs, being the firsts superior to the seconds.…”

“…In this way, their contribution in the Van Deemter's equation would be reduced resulting in high chromatographic efficiency. However, when these small particles are employed for chiral separation on polysaccharide‐based CSPs, the effect was not so clear .…”

Three versus five micrometer chlorinated polysaccharide‐based packings in chiral capillary electrochromatography: efficiency and precision evaluation

“…In a preceding study, three out of four 3 µm CSPs separated more compounds of the test set than their corresponding 5 µm counterparts (Hendrickx et al ., ). However, when considering the number of baseline separations, 5 µm LC2 and LA2 resolved more compounds than the equivalent 3 µm columns that is, four vs three, and 10 vs five compounds, respectively.…”

“…In earlier research on the performance evaluation, it was studied whether 3 µm particle size packings indeed perform better than their 5 µm counterparts by comparing the obtained retention times ( t R ), retention factors ( k ), efficiencies ( N ), and resolutions ( R s ) (Hendrickx et al ., ). Four chlorinated polysaccharide‐based CSPs, that is, amylose tris (5‐chloro‐2‐methylphenylcarbamate) (Lux Amylose‐2; LA2), cellulose tris (4‐chloro‐3‐methylphenylcarbamate) (Lux Cellulose‐4; LC4), cellulose tris (3‐chloro‐4‐methylphenylcarbamate) (Lux Cellulose‐2; LC2), and cellulose tris (3,5‐dichlorophenylcarbamate) (Sepapak‐5; Sp5), each of 3 and 5 µm particle size, were used to analyze a test set of 44 structurally and chemically diverse nonacidic compounds.…”