Capillary electrophoretic separation of biologically active amines and acids using nanoparticle‐coated capillaries

Abstract

This manuscript describes dynamic coating of capillaries with poly(L-lysine) (PLL) and silica nanoparticles (SiO 2 NPs) and use of the as-prepared capillaries for the separation of biogenic amines and acids by CE in conjunction with LIF detection. The directions of EOF are controlled by varying the outmost layer of the capillaries with PLL and SiO 2 NPs, respectively. Over the pH range 3.0-5.0, the (PLL-SiO 2 NP) n -PLL capillaries have an EOF toward the anodic end and are more suitable for the separation of acids with respect to speed, while the (PLL-SiO 2 NP) n capillaries have an EOF toward the cathodic end and are more suitable for the separation of biogenic amines regarding speed and sensitivity. The separations of standard solutions containing five amines and two acids by CE with LIF detection using (PLL-SiO 2 NP) 2 -PLL and (PLL-SiO 2 NP) 3 capillaries were accomplished within 10 and 7 min, providing plate numbers of 3.8 and 5.0610 4 plates/m for 5-hydroxytryptamine (5-HT), respectively. The LODs for 5-HT and 5-hydroxyindole-3-acetic acid (5-HIAA) are 32 and 2 nM and 0.2 and 1.5 nM when using the (PLL-SiO 2 NP) 2 -PLL and (PLL-SiO 2 NP) 3 capillaries, respectively. Identification and quantification of 5-HIAA, homovanillic acid, and DL-vanillomandelic acid in urine samples from a male before and after drinking green tea were tested to validate practicality of the present approach. The results show that the (PLLSiO 2 NP) 2 -PLL capillary provides greater resolving power, while the (PLL-SiO 2 NP) 3 capillary provides better sensitivity, higher efficiency, and longer durability for the separation of the amines and acids.

Multi‐walled carbon nanotube composites with polyacrylate prepared for open‐tubular capillary electrochromatography

“…Some Jian-Lian Chen Te-Ling Lu Yi-Chen Lin nanomaterials, including latex [11], lipoprotein [12,13], silica [14,15], titanium oxide [16,17], gold [18][19][20], and carbon nanotubes (CNT) [21][22][23][24][25], have been used in OT-CEC. However, only a few examples involved in chemical bonding of these materials onto OT capillaries exist.…”

Sensitive profiling of biogenic amines in human urine by capillary electrophoresis with field amplified sample injection

“…With a proper selection of the running buffer and operating procedures, FASI proved to be powerful for sample enrichment, resulting in remarkable improvement in LODs compared with conventional CE pressure injection mode. The achieved LODs (at S/N = 3) were the same order of magnitude as those of an expensive LIF detection (Huang et al ., ). Concerning the enrichment factors, FASI pre‐concentration had a sensitivity ca 600‐fold higher compared with normal CE.…”

Sensitive profiling of biogenic amines in urine using CE with transient isotachophoretic preconcentration

“…The achieved LODs (at S/N 5 3) were in the range approaching the sensitivity ability of LIF detection for given analytes. For instance, the LOD value reported for 5-HT is 0.03 mM [7]. Of alternative inline preconcentration techniques, merely SPE provides a competitive sensitivity: 0.020 mM for DA [26]; however, only standard solutions were considered in that study.…”

“…Most part of the current research is aimed to address the concentration sensitivity issue by adopting high-sensitive detectors, developing inline preconcentration techniques, or combining these approaches. With respect to the detection strategies for urinary biogenic amines, LIF appears to be one of the few options advanced to real-sample analysis [6][7][8]. However, only aromatic amines, having native fluorescence, can be determined using LIF-CE.…”