Simultaneous determination of salicylamide and salsalate in serum and urine by first derivative variable-angle synchronous fluorescence spectrometry

Rapid simultaneous determination of four non-steroidal anti-inflammatory drugs by means of derivative nonlinear variable-angle synchronous fluorescence spectrometry

A rapid, simple, and inexpensive spectrofluorimetric method has been proposed for the simultaneous quantification of diflunisal, salicylic acid, fenoprofen, and 6-methoxy-2-naphthylacetic acid (6MNA). First-derivative nonlinear variable-angle synchronous fluorescence spectrometry has been developed to improve the selectivity of fluorescence measurements without loss of sensitivity. It allows the simultaneous determination of different substances in a mixture from a single spectrum based on a single scan. The analyses were performed in an ethanol-water (70%) medium at a pH of 9.2, adjusted by using ammonium/ammonia (0.5 M) as a buffer solution. The linear concentration ranges are 30.0-100.0, 100.0-600.0, 50.0-150.0, and 30.0-100.0 ng/mL for salicylic acid, fenoprofen, diflunisal, and 6-methoxy-2-naphthylacetic acid, respectively, at lambda(ex)/lambda(em) = 281.1/423.6, 241.2/301.2, 284.1/403.8, and 268.7/339.6 nm, respectively. Analytical parameters of the proposed method were calculated according to the error propagation theory. The sensitivity, repeatability, reproducibility, and limits of detection achieved with the proposed method are adequate for the determination of these anti-inflammatory drugs.

A simple and rapid fluorimetric method for simultaneous determination of protoporphyrin IX and zinc protoporphyrin IX in whole blood

Derivative variable-angle synchronous fluorescence (DVASF) spectrometry improves the spectral resolution and selectivity of the fluorescence method. The feasibility of DVASF spectrometry for the simultaneous determination of protoporphyrin IX (PP) and zinc protoporphyrin IX (ZnPP) was investigated. PP and ZnPP were distinguished from each other simultaneously and rapidly by the DVASF method. The spectra were resolved well, and the two components were determined in a single scan, avoiding the spectral compensation factor for PP and chromatographic separation. The linear range of the calibration curve for PP was from 0.190 to 152 nmol/L and for ZnPP was from 0.383 to 230 nmol/L. The detection limits of PP and ZnPP were 0.098 nmol/L and 0.088 nmol/L, respectively. The within-run imprecision (RSD, n = 5) for PP was 4.1%, and for ZnPP was 4.2%. Mean recoveries (SD) of PP and ZnPP added to a blood sample were 86.4 (7.3)% and 72.9 (6.6)%, respectively. This method should be a potential tool in the rapid routine screening of large quantities of samples.

Rapid screening method for simultaneous determination of four polycyclic aromatic hydrocarbons in water samples by derivative non-linear variable-angle synchronous fluorescence spectrometry

Derivative non-linear variable-angle synchronous fluorescence spectroscopy (D-NLVASFS) has been developed to improve the selectivity of the fluorescence measurement without loss of sensitivity. We report a simple screening approach for the rapid and simultaneous determination of 1,2.5,6-dibenzoanthracene (DBA), 2,3-benzofluorene (BF), pyrene (Pyr) and 3,4-benzopyrene (BaP) in a mixture by using first-derivative NLVASFS. The method is efficient, fast and straightforward, and the measurement was simply based on a single spectrum via a single spectral scanning of a sample. The linear ranges 0.005-0.30, 0.02-0.30, 0.02-0.40 and 0.005-1.0 microg/mL and the detection limits 0.08, 1.14, 1.64 and 0.12 ng/mL are obtained for DBA, BF, Pyr and BaP, respectively. The method was applied to water samples spiked with the four polycyclic aromatic hydrocarbons (PAHs), with mean recoveries of 103.0% (SD 5.9%) for DBA, 96.4% (SD 4.2%) for BF, 96.2% (SD 4.0%) for Pyr and 98.2% (SD 3.0%) for BaP.