Chowdhury S K, Katta V, Chait B T
Rockefeller University, New York 10021.
Rapid Commun Mass Spectrom. 1990 Mar;4(3):81-7. doi: 10.1002/rcm.1290040305.
The construction and performance of an electrospray-ionization mass spectrometer with new features are described. The mass spectrometer consists of a newly designed electrospray ion-source that is plugged directly into a modified commercial quadrupole mass spectrometer with the ions entering the mass analyzer through a long metal capillary tube and three stages of differential pumping. The present ion source differs from previous designs in the combination of techniques employed in the transportation and desolvation of solvated biomolecule ions, prior to mass analysis. Transport of ionized entities between atmospheric pressure and vacuum is carried out through a 203 mm long stainless steel capillary tube with a 0.5 mm bore. Desolvation is effected by the use of controlled heat transfer through the long capillary tube and collisional activation in a region of reduced pressure between the capillary tube exit and the skimmer. Desolvation with this system is convenient and effective and does not involve the strong countercurrent flows of gases that have been used by all previous workers. The effects on the spectra of peptides of capillary tube temperature and desolvation collision energy are investigated. Electrospray-ionization mass spectrometric results are described for thirteen proteins with molecular masses ranging from 5000 to 77,000 Da. The performance of the present instrument, with respect to mass accuracy and sensitivity, is comparable with previously reported systems. The effect of protein concentration in solution on the electrospray mass spectrometric response and charge-state distribution is discussed.
本文描述了一种具有新特性的电喷雾电离质谱仪的构造与性能。该质谱仪由一个新设计的电喷雾离子源组成，该离子源直接接入一台经过改装的商用四极质谱仪，离子通过一根长金属毛细管进入质量分析器，并采用三级差动抽气。当前的离子源与先前设计的不同之处在于，在质量分析之前，用于溶剂化生物分子离子的传输和去溶剂化的技术组合有所不同。电离实体在大气压和真空之间的传输是通过一根内径为0.5毫米、长203毫米的不锈钢毛细管进行的。去溶剂化是通过控制热量通过长毛细管传递以及在毛细管出口和撇油器之间的减压区域进行碰撞活化来实现的。使用该系统进行去溶剂化既方便又有效，并且不涉及所有先前研究者所使用的强烈气体逆流。研究了毛细管温度和去溶剂化碰撞能量对肽谱的影响。描述了对13种分子量范围从5000到77,000道尔顿的蛋白质进行电喷雾电离质谱分析的结果。就质量精度和灵敏度而言，当前仪器的性能与先前报道的系统相当。讨论了溶液中蛋白质浓度对电喷雾质谱响应和电荷态分布的影响。
