Fluorescent kinetics combined with fourth-order calibration for the determination of diclofenac sodium in environmental water.

A method that combines five-way fluorescence kinetics with fourth-order calibration for interference-free quantification of diclofenac sodium in river water was proposed and tested. Traditional fluorescence methods may not be suitable for such measurements since the fluorescence properties of the analyte are highly dependent on both pH and irradiation time in situ. In the method considered here, a five-way emission-excitation-time-pH data array was obtained from the samples by introducing the pH level and irradiation time as two extra modes. Then the data array was resolved by three fourth-order calibration algorithms: alternating fitting weighted residue quinquelinear decomposition (AFWRQQLD), five-way parallel factor analysis (five-PARAFAC), and alternating quinquelinear decomposition (AQQLD). The average recoveries and detection limits calculated for diclofenac sodium in a set of analyte-spiked river water samples using AFWRQQLD, five-PARAFAC, and AQQLD were 97.2 ± 3.2% and 1.9 ng mL-1, 96.8 ± 3.0% and 4.0 ng mL-1, and 92.6 ± 2.7% and 2.5 ng mL-1, respectively. A study of other figures of merit, statistical analysis, an elliptical joint confidence region test, and a t-test were additionally carried out to validate the analytical performance of the proposed method in detail. The results demonstrated that this new method required only two steps (fluorescence measurement and algorithm analysis) to determine the analyte concentration. It could therefore provide the basis for developing novel reliable and sensitive approaches for the accurate detection of pharmaceutical pollutants with unstable fluorescence properties in real complex matrices such as environmental water samples. Graphical Abstract ᅟ.

[Variation of sperm DNA fragmentation index in male partners from infertile couples].

OBJECTIVE: To investigate variation of sperm DNA fragmentation index (DFI) in male partners of infertile couples. METHODS: A total of 539 males between April 2009 and April 2012 were analyzed. At least one repeated routine semen analysis and sperm DNA fragmentation test were performed for each sample by sperm chromatin dispersion (SCD) analysis following World Health Organization guidelines. Coefficient of variation (CV) for DFI was calculated. RESULTS: Respectively, 1, 2, 3 and 4 repeated SCD analyses were carried out on 473, 59, 6 and 1 semen samples. The median interval between the first and repeated SCD measurements was 3.0 (1.0-11.0) months. For the first tested samples, the between-sample coefficient of variation (CVB) for DFI was 71.2%. A significant difference has been found between DFI of the first measurement and DFI of repeated measurement in 0.5 to 3 months, 3 to 12 months and 12 to 34 months (P< 0.01). Compared with the first test, 26.3% of males were on both sides of the cut-off point of 18%. The median within-subject coefficient of variation (CVw) for DFI of 539 men was 26.0% (12.6%-42.8%). And the median CVw DFI was significantly lower compared with CVw of sperm count, concentration, progressive motility and normal morphology (P< 0.01). Significant correlations were found between the CVw DFI and sperm count, concentration and interval among the samples (P< 0.05). CONCLUSION: DFI of male partners for infertile couples is a parameter with substantial variation, repeated SCD measurements are therefore recommended.