Derivative matrix-isopotential synchronous spectrofluorimetry: a solution for the direct determination of urinary δ-aminolevulinic acid

The excitation and emission spectra formulated 3D contours, from which isopotential trajectory was selected for the direct detection of urinary δ-aminolevulinic acid, using derivative matrix isopotential synchronous fluorescence spectrometry.

Determination of trace fluoroquinolones in water solutions and in medicinal preparations by conventional and synchronous fluorescence spectrometry

Simple, rapid and sensitive and synchronous fluorescence spectrometry (SFS) were developed for determination the fluoroquinolones of ciprofloxacin (CIP), norfloxacin (NOR) and enrofloxacin (ENR) separately in water solutions and in medicinal preparations. The optimized wavelength intervals between the emission and excitation wavelengths were 170 nm, 160 nm and 170 nm for CIP, NOR and ENR, respectively. The different experimental parameters affecting the synchronous fluorescence intensities of the three fluoroquinolones were carefully studied. Under the optimal conditions, good linearity was obtained over the range of 0.01 to 1.20 mg/L, 0.005 to 0.45 mg/L and 0.005 to 0.60 mg/L for the CIP, NOR and ENR, and with good relative standard deviations below 1.9% (n=9). In addition, the detection limits for CIP, NOR and ENR were 0.17 μg/L, 0.013 μg/L and 0.055 μg/L, respectively. What is more, compared with the conventional fluorescence spectrometry, the SFS could detect lower concentrations of each fluoroquinolone. Moreover, the proposed SFS were validated and successfully applied for the quantitative assay of each fluoroquinolone in medicinal preparations.

Determination of enantiomeric composition of fluoxetine by synchronous fluorescence spectrometry coupled with multivariate calibration in biological samples

This paper presents rapid and low cost analytical method for the determination of the fluoxetine enantiomeric composition in biological samples (urine). The combination of synchronous fluorescence spectrometry and inverse multivariate calibration methods was used. The chiral recognition of the fluoxetine was based on the creating of the diastereomeric complexes with β-cyclodextrin. A net analytical signal of diastereomeric complexes was obtained by the addition of aliquot part of urine into calibration and validation sets. This step ensures the elimination of the urine matrix effect. The synchronous fluorescence spectra at the constant wavelength differences (Δλ) of 30 and 50 nm, based on RMS %RE values, were chosen for chemometric analysis. Principal component regression (PCR) and partial least square method (PLS) were compared to determine the enantiomeric composition. The most suitable results were provided by the PLS model constructed from the synchronous data at Δλ = 50 nm. The calculated figure of merit was used for validation of proposed method.