More rapid and sensitive method for simultaneous determination of tryptophan and kynurenic acid by HPLC

Optimization of Zn2+-containing mobile phase for simultaneous determination of kynurenine, kynurenic acid and tryptophan in human plasma by high performance liquid chromatography

“…This was a remarkable improvement for the determination of ultra-trace level of KYNA in biological samples. Though it was reported [29] that LOD of KYNA could reach to 0.05 nmol/L by using mobile phase containing 0.5 mol/L ZnAc 2 , so high concentration of Zn 2+ would cause severe clotting risk [8].…”

“…The E ZnAc 2 were 6.6, 5.0, 4.2, 3.7 and 3.5 corresponding to 1 mmol/L, 2 mmol/L, 3 mmol/L, 4 mmol/L, and 5 mmol/L ZnAc 2 in mobile phase. The method reported by Lan-Gan et al [29] used 500 mmol/L ZnAc 2 , which produced 50-fold increase of the fluorescence intensity. Its E ZnAc 2 was only 0.1, which was much lower than that by using low concentration of ZnAc 2 .…”

“…There were no statistically significant differences for all analytes (Table 4). [29] a Signal/noise ratio = 3.…”

“…Some authors [14,17,23,24] delivered Zn 2+ through post-column. Others [5,9,10,[25][26][27][28][29] simply used a Zn 2+ -containing mobile phase by addition of 0.1-0.5 mol/L ZnAc 2 with or without pH adjustment. So high concentration of ZnAc 2 would cause technical solubility problem and clotting risk which could hamper HPLC procedures and results [8,25].…”

Quantification of tryptophan in plasma by high performance liquid chromatography

“…1,4,8,11,14,17 However, the chromatographic techniques are well-known for their use (sometimes in large quantities) of environmentally hazardous organic solvents and can affect human health. 18 Current recommendations encouraged the use of smaller amounts of these solvents (or none), aiming to achieve safer methods of analysis, without compromising their performance: this can be considered the pillar of the so-called "green chemistry".…”