Betacyanins from vine cactus Hylocereus polyrhizus.

The presence of betacyanin pigments and their isoforms has been detected in the fruit of Hylocereus polyrhizus, a vine cactus native to South America. Along with the known betanin and phyllocactin (6'-O-malonylbetanin), a new betacyanin was structurally elucidated as betanidin 5-O-[6'-O-(3"-hydroxy-3"-methyl-glutaryl)-beta-D-glucopyranoside] (proposed trivial name hylocerenin) by means of electrospray MS/MS, HPLC, and NMR techniques.

Modified sampling and analysis method for large volatility range airborne polycyclic aromatic hydrocarbons (PAH) using gas chromatography-mass spectrometry.

A sampling method has been developed for the measurement for polycyclic aromatic hydrocarbons in ambient air by gas chromatography isotope dilution mass spectrometry. The method has been designed to measure the largest possible volatility range of PAHs including the abundant naphthalenes. Sample volumes were approx. 500 m(3) in size at a sampling rate of approx. 18 m(3)/h. The sampler contained three sorption stages for the simultaneous capturing of particle bound and low and high volatile gaseous PAH, respectivley. Recoveries of sampling spikes were on average 90%. The detection limit was approx. 5 pg/m(3) for the high boiling range PAH. Results obtained showed a quite steady profile for most PAH in background air in The Netherlands. Comparison of abundance ratios with literature data indicate that traffic exhausts are the major source for the PAH in the area.