[Simultaneous determination of 27 solvent residuals in ultraviolet curable offset inks by headspace gas...

A headspace gas chromatography-mass spectrometry (HS-GC-MS) method was developed for the determination of 27 solvent residuals (volatile organic compounds, VOCs) in ultraviolet (UV) curable offset inks. Ink samples of a given area and thickness were prepared using an ink-scraping instrument and baked under a UV lamp for 1 min. The experimental conditions such as headspace temperature and time, and the GC-MS analytical conditions, were optimized. The ink samples were treated at 80℃ for 45 min, and the evolved products were separated on a special VOC column, identified by MS, and quantified by an external-standard method. The calibration curves for all 27 VOCs showed good linearity with correlation coefficients (R²) no lower than 0.9950. The limits of detection (S/N=3) were in the range of 0.001-0.310 mg/m² and the limits of quantification (S/N=10) were in the range of 0.003-0.920 mg/m². The average recoveries of the 27 VOCs ranged from 80% to 108% at various spiked levels, with relative standard deviations less than 6% (n=6). Thus, this method has a high sensitivity and good precision and accuracy, and it is suitable for the determination of 27 solvent residuals in various UV offset inks.