18-FDG-PET and the prognosis in patients with pancreatic carcinoma

A new method was developed for separation and quantification of nitrosamines by micellar electrokinetic capillary chromatography (MEKC). The effects of composition of the buffer, concentration of sodium dodecyl sulfate (SDS), γ-cyclodextrin (CD) and pH on the separation and migration times of the nitrosamines were investigated. The different instrumental variables affecting sensitivity and resolution, such as power supply, injection mode and wavelength for measurement, were carefully optimized. The direct application of this method to aqueous synthetic samples allowed the separation and determination of nitrosamine mixtures at the mg L−1 level. The calibration curves revealed a linear range between 0.25 and 10 mg L−1, with detection limit (DL) varying from 0.16 to 0.27 mg L−1, quantification limit (QL) varying from 0.52 to 0.90 mg L−1, and RSD relative standard deviation (RSD) from 4.5% to 8.5%. The proposed method was successfully applied to the determination of dimethylnitrosamine (DMN), diethylnitrosamine (DEN), N-nitrosopyrrolidine (NPYR), N-nitrosomorpholine (NMOR) and N-nitrosopiperidine (NPIP).