A multi-analytical approach for the assessment of the provenience of geological amber: the collection of the Earth Sciences Museum of Bari (Italy).

The Earth Sciences Museum of the University of Bari Aldo Moro (Italy) exhibits a wide collection of amber samples. These have been catalogued as Baltic amber (succinite), Sicilian amber (simetite), amber from New Jersey, Apennine amber and New Zealand copaline. However, some samples revealed to be erroneously classified as a consequence of incorrect information on the labels or in the museum catalogue. This may be due to historical forgeries, as is often the case of simetite, or to a possible exchange of samples that probably occurred during the displacement of the museum collection from the Central University Building to the Geo-environmental and Earth Sciences Department. In this study, all amber samples were systematically investigated with long wave UV rays, attenuated total reflectance (ATR), Fourier transform infrared (FTIR) spectroscopy and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) using on-line thermally assisted hydrolysis and methylation. The combined use of the latter two analytical techniques allowed for a complete characterisation of the ambers, whereas UV fluorescence showed to be of little value. The compositional data could be used for a better classification and valorisation of the amber samples of the museum collection. Two of the purported amber samples were shown to be copal, while four others are ambers but had been wrongly classified. Moreover, for some samples, it could be established that they had been subjected to treatment with a drying oil.

Determination of glycoalkaloids and relative aglycones by nonaqueous capillary electrophoresis coupled with electrospray ionization-ion trap mass spectrometry.

Glycoalkaloids are naturally occurring nitrogen-containing compounds present in many species of the family Solanaceae, including cultivated and wild potatoes (Solanum spp.), tomatoes (Lycopersicon spp.), etc. These compounds have pharmacological and toxicological effects on humans due to their significant anticholinesterase activity and disruption of cell membranes. Herein is reported the development of a capillary electrophoresis (CE) method using nonaqueous (NA) separation solutions in combination with ion trap mass spectrometry (MS and MS/MS) detection for the identification and quantification of glycoalkaloids and their relative aglycones. A mixture 90:10 v/v of MeCN-MeOH containing 50 mM ammonium acetate and 1.2 M acetic acid (applied voltage of 25.5 kV) was selected as a good compromise for the separation and detection of these compounds. The electrospray MS measurements were carried out in the positive ionization mode using a coaxial sheath liquid, methanol-water (1:1) with 1% of acetic acid at a flow rate of 2.5 microL/min. Under optimized experimental conditions, the predominant ion was the protonated molecular ion ([M+H](+)) of solanidine (m/z = 398), tomatidine (m/z = 416), chaconine (m/z = 852), solanine (m/z = 868), and tomatine (m/z = 1034). MS/MS experiments were carried out systematically by changing the relative collisional energy and monitoring the intensities of the fragment ions that were not high enough to allow better quantification than with the mother ions. The method was used for analyzing glycoalkaloids in potato extracts.