New Spectrofluorimetric Method for Determining Serotonin: Application to Human Urine

Abstract

In this present paper, we investigate the development of simple, rapid, accurate, reproducible and sensitive methods for the determination of serotonin (5-HT) in urine. For this purpose stationary fluorescence was used as method. With regard to the analysis of serotonin, the liquid-liquid extraction (LLE) solid phase extraction (SPE) and standard addition procedures were used. Several physicochemical factors affecting the sensitivity of the fluorescence intensity of serotonin were optimized, including the system of solvent (organic, micellar), the pH and the salts. The study of the analytical performances of the method led to very low limits of detection (LOD) varying between 0.1 and 3 ng/mL and to limits of quantification (LOQ) ranging between 0.4 and 10 ng/mL. This confirms the sensitivity of the method. Thus the low values of standard deviations (DRS) (between 0.3 and 6.6%) testify the good reproducibility of the measurements with satisfactory covering rate (89 to 111%). Accordingly, our results show that the spectrofluorimetric method is simple, fast and sensitive and can be applied to the routine analysis and does not require expensive equipment nor tiresome chemical pretreatments.Keywords: serotonin, effects of solvent, method of analysis of fluorescence direct, analysis of urine

New Spectrofluorimetric Method for Determining Cadaverine Following Derivation with Orthophthalaldehyde: Application in Fish Tissue

“…This increase in temperature causes the dissociation of the complex, which causes a reduction of the fluorescence intensity. This observation is in agreement with that reported in the literature (Khonté et al, 2015) . This process is reversible, because by cooling the solution, we observed an increase in fluorescence intensity due to the reconstitution of the complex.…”

“…The relative standard deviation was low (5.19%) attesting to the good precision of our measurements (Table 2). These values were consistent with international standards for the validation of the analytical method (Khonté et al, 2015). Researchers have obtained a recovery percentage of 97% for mackerel (Richard, Pivarnik, Ellis, & Lee, 2011).…”

“…The slopes of the calibration curves and standard addition are very close (Figure 8). This parallelism of the two curves indicated lower sensitivity to interfering substances and negligible matrix effect (Khonté et al, 2015). This was confirmed by the satisfactory percentage recovery between 82.4 and 97.7 (Table 2).…”

“…In buffer solution pH 3.5, the fluorescence signal is highest for the water/MeOH mixture (95:5, v/v), while at neutral pH, methanol progressively inhibits the fluorescence signal. The progressive decrease in the fluorescence intensity with the addition of large amounts of MeOH could be due to the phenomenon of salvation (Khonté et al, 2015) . In addition, the continuous addition of methanol in the reaction medium increases the dissociation of OPA/CD complex where there is a decrease in the observed fluorescence intensity.…”

“…This, regardless of the fat content, the handling conditions and the size of the fish sample (Richard, Pivarnik, Ellis, & Lee, 2011). Furthermore, for a better quantitative analysis of cadaverine in the sample, we prepared an additional curve to evaluate the degree of interference of other substances present in the matrix (Diaw et al, 2014, Khonté et al, 2015,. The slopes of the calibration curves and standard addition are very close (Figure 8).…”