Kertesz Vilmos, Van Berkel Gary J
Organic and Biological Mass Spectrometry Group, Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831-6131, USA.
Rapid Commun Mass Spectrom. 2008 Dec;22(23):3846-50. doi: 10.1002/rcm.3812.
The position of the surface to be analyzed relative to the sampling orifice or capillary into the mass spectrometer has been known to dramatically affect the observed signal levels in desorption electrospray ionization mass spectrometry (DESI-MS). In analyses of sample spots on planar surfaces, DESI-MS signal intensities as much as five times greater were routinely observed when the bottom of the sampling capillary was appropriately positioned beneath the surface plane ('edge sampling') compared with when the capillary just touched the surface. To take advantage of the optimum 'edge sampling' geometry and to maximize the number of samples that could be analyzed in this configuration, a rotational sample stage was integrated into a typical DESI-MS setup. The rapid quantitative determination of caffeine in two diet sport drinks spiked with an isotopically labeled internal standard demonstrated the utility of this approach.
在解吸电喷雾电离质谱法（DESI-MS）中，待分析表面相对于质谱仪采样孔或毛细管的位置会显著影响观察到的信号水平，这是已知的。在分析平面表面上的样品点时，与毛细管仅接触表面相比，当采样毛细管底部适当地位于表面平面下方（“边缘采样”）时，通常观察到的DESI-MS信号强度要高出多达五倍。为了利用最佳的“边缘采样”几何结构并最大化在此配置下可分析的样品数量，将旋转样品台集成到典型的DESI-MS装置中。对添加了同位素标记内标的两种运动饮料中的咖啡因进行快速定量测定，证明了该方法的实用性。
