. "Caffeine; Coffee; Direct analysis in real time; Ambient mass spectrometry"@en . "7"^^ . "RIV/60461373:22330/12:43894787" . "7"^^ . "I, Z(MSM6046137305)" . . . . . . "22330" . "000305519400012" . "10" . "The development and use of a fast method employing a direct analysis in real time (DART) ion source coupled to high-resolution time-of-flight mass spektrometry (TOFMS) for the quantitative analysis of caffeine in various coffee samples has been demonstrated in this study. A simple sample extraction procedure employing hot water was followed by direct, high-throughput ({1 min per run) examination of the extracts spread on a glass rod under optimized conditions of ambient mass spectrometry, without any prior chromatographic separation. For quantification of caffeine using DART-TOFMS, an external calibration was used. Isotopically labeled caffeine was used to compensate for the variations of the ion intensities of caffeine signal. Recoveries of the DART-TOFMS method were 97% for instant coffee at the spiking levels of 20 and 60 mg/g, respectively, while for roasted ground coffee, the obtained values were 106% and 107% at the spiking levels of 10 and 30 mg/g, respectively. The repeatability of the whole analytical procedure (expressed as relative standard deviation, RSD, %) was {5% for all tested spiking levels and matrices. Since the linearity range of the method was relativem narrow (two orders of magnitude), an optimization of sample dilution prior the DART-TOFMS measurement to avoid saturation of the detector was needed."@en . . . "RIV/60461373:22330/12:43894787!RIV13-MSM-22330___" . "10.1007/s00216-012-5820-2" . "DE - Spolkov\u00E1 republika N\u011Bmecko" . "V\u00E1clav\u00EDk, Luk\u00E1\u0161" . . . "1618-2642" . "Rapid analysis of caffeine in various coffee samples employing direct analysis in real-time ionization-high-resolution mass spectrometry" . . . "Rapid analysis of caffeine in various coffee samples employing direct analysis in real-time ionization-high-resolution mass spectrometry" . . "Da\u0148helov\u00E1, Hana" . "164085" . . . "P\u0159inosilov\u00E1, \u0160\u00E1rka" . "The development and use of a fast method employing a direct analysis in real time (DART) ion source coupled to high-resolution time-of-flight mass spektrometry (TOFMS) for the quantitative analysis of caffeine in various coffee samples has been demonstrated in this study. A simple sample extraction procedure employing hot water was followed by direct, high-throughput ({1 min per run) examination of the extracts spread on a glass rod under optimized conditions of ambient mass spectrometry, without any prior chromatographic separation. For quantification of caffeine using DART-TOFMS, an external calibration was used. Isotopically labeled caffeine was used to compensate for the variations of the ion intensities of caffeine signal. Recoveries of the DART-TOFMS method were 97% for instant coffee at the spiking levels of 20 and 60 mg/g, respectively, while for roasted ground coffee, the obtained values were 106% and 107% at the spiking levels of 10 and 30 mg/g, respectively. The repeatability of the whole analytical procedure (expressed as relative standard deviation, RSD, %) was {5% for all tested spiking levels and matrices. Since the linearity range of the method was relativem narrow (two orders of magnitude), an optimization of sample dilution prior the DART-TOFMS measurement to avoid saturation of the detector was needed." . . "Rapid analysis of caffeine in various coffee samples employing direct analysis in real-time ionization-high-resolution mass spectrometry"@en . "Hradeck\u00FD, Jarom\u00EDr" . "Analytical and Bioanalytical Chemistry" . "[2A2F556CB26A]" . . . . "\u010Cajka, Tom\u00E1\u0161" . . . "403" . . . "Haj\u0161lov\u00E1, Jana" . . "Rapid analysis of caffeine in various coffee samples employing direct analysis in real-time ionization-high-resolution mass spectrometry"@en . "Riddellov\u00E1, Kate\u0159ina" . "7"^^ .