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Capillary zone electrophoresis (CZE) was coupled to mass spectrometry (MS) via a nanoelectrospray interface (nESI), using conductively coated tips (8 mm orifice) butted to the end of a fused-silica capillary. The CZE/nESI-MS system was carefully optimised to achieve a stable operation of the arrangement in order to run also MS/MS experiments. Mixtures of b-agonists were successfully separated using 5 mmol/L ammonium acetate in 80% MeOH as a buffer. The limit of detection was 500 attomole of a substance injected. The system was also investigated from the point of view of quantification of the substances. Careful measures were taken to avoid any systematic errors (evaporative loss during the electrokinetic injection and reduction of migration times due to the electrospray pull during the CE run). The data show that the response of a mass spectrometric detector in the low-femtomole range not only depends on the concentration of the analyte but also on the properties of the nanoelectrospray process itself, that is why the linearity of the response can be compromised.

Purpose Cholangiocarcinoma (CCA) is a malignancy arising from the bile duct epithelium and has a poor outcome. Sulfatides are lipid components of lipid rafts, and are implicated in several cancer types. In the liver, sulfatides are specifically present in the bile ducts. Here, sulfatide abundance and composition were analyzed using mass spectrometry imaging in intrahepatic CCA (iCCA) tumor tissue, and correlated with tumor biology and clinical outcomes. Methods Sulfatides were analyzed in iCCA (n = 17), hepatocellular carcinoma (HCC, n = 10) and colorectal liver metastasis (CRLM, n = 10) tumor samples, as well as tumor-distal samples (control, n = 16) using mass spectrometry imaging. Levels of sulfatides as well as the relative amount in structural classes were compared between groups, and were correlated with clinical outcomes for iCCA patients. Results Sulfatide localization was limited to the respective tumor areas and the bile ducts. Sulfatide abundance was similar in iCCA and control tissue, while intensities were notably higher in CRLM in comparison with control (18-fold, P < 0.05) and HCC tissue (47-fold, P < 0.001). Considerable variation in sulfatide abundance was observed in iCCA tumors. A high ratio of unsaturated to saturated sulfatides was associated with reduced disease-free survival (10 vs. 20 months) in iCCA. The sulfatide pattern in HCC deviated from the other groups, with a higher relative abundance of odd- versus even-chain sulfatides. Conclusion Sulfatides were found in tumor tissue of patients with iCCA, with sulfatide abundance per pixel being similar to bile ducts. In this explorative study, sulfatide abundance was not related to overall survival of iCCA patients. A high ratio of unsaturated to saturated sulfatides was associated with earlier tumor recurrence in patients with iCCA.

A straightforward and reliable method was developed for the determination of chlormequat in pears by liquid chromatography/mass spectrometry (LC/MS). Water and methanol were compared as extraction solvents. Because no significant differences in extraction efficiency or repeatability were found, water was chosen as the extraction solvent. The extracts were analyzed without cleanup by either an ion-trap liquid chromatograph/mass spectrometer in the single MS mode or a triple-quadrupole instrument in the MS/MS mode, using electrospray ionization. Both instruments were equally suitable for quantitation and confirmation of identity. Recoveries were 76–103%, and reproducibility was ≤12%. The lowest detection limit (0.007 mg/kg) was obtained with the triple-quadrupole instrument in the MS/MS mode.