The Mass Spectrometry Facility at Boston College Chemistry maintains a wide range of state-of-the-art mass spectrometers and chromatographic systems, providing the full suite of ionization and separation options that are capable of dealing with all sample types and a wide array of client demands. Ionization methods available include ESI, APCI, APPI, DART, and AP-MALDI, all of which are capable of operating in both the positive and negative ion modes.
Samples are generally run by the facility staff, and the results are provided as electronic data files. In special circumstances, an individual researcher who makes frequent use of a particular spectrometer may receive training and become authorized to run samples personally. Such authorized users then often run samples for other members of their own research group to reduce the pressure on the facility staff.
Complete Facility Description
Micromass LCT TOF
JEOL AccuTOF DART
Agilent 6210 Time-of-Flight LC/MS
1. Micromass LCT TOF
The Micromass LCT system comprises a high performance orthogonal acceleration reflecting time-of-flight mass spectrometer, coupled to a Waters 2975 HPLC and a Waters 2996 photodiode array UV-vis detector. The mass spectrometer utilizes a Z–flow atmospheric pressure ionization source; samples can be introduced by electrospray ionization (ESI) or atmospheric pressure chemical ionization (APCI). The Waters Alliance LC is designed specifically for high throughput liquid chromatography-mass spectrometry (LC/MS) and is fully integrated with the mass spectrometer's MassLynx software. The Micromass LCT Mass Spectrometer combines the sensitivity of LC/MS with simple, automated exact mass measurement. The high quality data delivered can provide information on elemental composition, structural characteristics and excellent specificity for identifying compounds in complex matrices or from a database search.
2. JEOL AccuTOF DART
The JEOL AccuTOF, configured with a new Direct Analysis in Real Time (DART) ion source, represents a significant breakthrough in mass spectrometry. It is the first mass spectrometer to allow the analysis of solids, liquids and gaseous samples at atmospheric pressure and ground potential by simply placing the sample between the DART and the mass spectrometer. No solvents or sample preparation are required. The system design results in high throughput with no carry over, even with neat polyethylene glycol (PEG). The DART can even analyze samples directly from a variety of surfaces such as concrete, currency, food, pills, clothing, and TLC plates. The AccuTOF DART combination achieves high specificity through high resolution. Exact mass measurements together with precise isotopic abundances can rapidly identify unknown compounds by their elemental compositions.
The DART ion source is based on the reactions of excited-state species with reagent molecules and polar or non-polar analytes. It is free of the limitations that are common to other atmospheric pressure ion sources, which require direct exposure of gaseous or vaporized liquid samples to elevated temperatures and electrical potentials, ultraviolet irradiation, laser radiation, or a high-velocity gas stream. DART does not alter the sample in any way, nor does it expose the user to a potentially harmful substance or dangerous situation.
3. Agilent 6210 Time-of-Flight LC/MS
The Agilent 6210 TOF LC/MS delivers exceptional analytical performance, including 2-ppm mass accuracy, and is ideal for protein and metabolite profiling. The powerful combination of resolving power and high mass accuracy allows identification of impurities in complex matrices faster and with greater confidence than with other methods. The instrument has a variety of ion source ESI, APCI, APPI and AP-MALDI meeting the widest range of applications.
The atmospheric pressure photoionization (APPI) source is especially useful for analyzing compounds that ionize poorly by ESI and APCI. It uses a krypton lamp that emits photons at energy levels high enough to ionize compounds with a UV chromophore, but low enough to minimize the ionization of air and common HPLC solvents. Relatively low ionization energy means the APPI source causes minimal fragmentation and generates mostly molecular ions and protonated molecules.
The atmospheric pressure matrix assisted laser desorption ionization (AP-MALDI) source provides fast, easy, and ultrasensitive analysis for samples that do not need online separation. It is ideal for protein identification and confirmation using peptide mass fingerprinting (PMF).
Coupled to the mass spectrometer, a 1200 series rapid resolution LC system offers a unique combination of flexibility, resolution and speed. Benefits include the ability to run both rapid resolution and conventional HPLC methods on the same chromatography system, which supports both standard and narrow bore columns. Rapid resolution, in turn, offers up to 60% higher resolution than conventional HPLC, with approximately 20 times faster analysis time, compared to standard HPLC.
