ANALYSIS OF XANTHATE DERIVATIVES BY VACUUM-ULTRAVIOLET LASER TIME-OF-FLIGHT MASS-SPECTROMETRY

A series of liquid O,S-dialkyl dithiocarbonates (xanthate esters) have been synthesized, and time-of-flight (TOF) mass spectra were recorded for their vapors using both ultraviolet (UV) and vacuum ultraviolet ( VUV) laser excitation. These compounds are chemical derivatives of low vapor pressure xanthate salts which have found important commercial a pplication as collectors in mineral sulfide notation circuits. Our exp eriments demonstrate that esters ionized by short-wavelength VUV light can be detected by parent mass with high efficiency and minimal fragm entation. In contrast, the mass spectra of the same compounds obtained by UV light excitation exhibit a large number of low molecular mass p eaks. A preliminary quantitative analysis of the composition of a gas- phase mixture of xanthate esters has also been achieved, which indicat es possible subfemtomole detection limits.