A Review of Combined Liquid Chromatography and Mass Spectrometry

Mass Spectrometric Identification of BSA Covalently Captured onto a Chip for Atomic Force Microscopy

Mass spectrometry (MS) is one of the main techniques for protein identification. Herein, MS has been employed for the identification of bovine serum albumin (BSA), which was covalently immobilized on the surface of a mica chip intended for investigation by atomic force microscopy (AFM). For the immobilization, two different types of crosslinkers have been used: 4-benzoylbenzoic acid N-succinimidyl ester (SuccBB) and dithiobis(succinimidyl propionate) (DSP). According to the data obtained by using an AFM-based molecular detector, the SuccBB crosslinker was more efficient in BSA immobilization than the DSP. The type of crosslinker used for protein capturing has been found to affect the results of MS identification. The results obtained herein can be applied in the development of novel systems intended for the highly sensitive analysis of proteins with molecular detectors.

Application of FRIT fast atom bombardment liquid chromatography/mass spectrometry for the determination of acetylcholine levels in rat brain regions

This report describes the use of FRIT fast atom bombardment (FAB) liquid chromatography/mass spectrometry for the analysis of acetylcholine in rat brain regions. Direct assessment of acetylcholine levels is possible without the need for either derivatization or extensive sample preparation. Quantification is accomplished by monitoring intact molecular cations of acetylcholine and a deuterated internal standard. The results are compared with those obtained by conventional pyrolysis gas chromatography/mass spectrometry and by liquid chromatography with electrochemical detection.

The enkephalin response in human tooth pulp to orthodontic force

Public perception is that dentistry and pain go hand in hand; thus, pain and pain control are important considerations to the profession. Recent studies have attempted to discover the precise metabolic events involved in neural transmission of nociceptive information. One focus has been the study of peptidergic pathways, which purportedly inhibit the firing of pain-conducting fibers. The research described in this article defined the existence of one enkephalin, methionine enkephalin (ME), in an extract of human tooth pulp tissue and the effect of orthodontic force on that ME concentration. One set of patients who had premolars extracted for orthodontic purposes served as controls. Another set, also diagnosed for premolar extractions, had a coil spring attached between the left and right maxillary premolars to supply an orthodontic force for a period of time prior to extraction. High-performance liquid chromatography, radioimmunoassay, radioreceptor assay, and mass spectrometry were used in a series of experiments to isolate, identify, and quantify ME in the pulp tissues. Principal results were as follows: for the first time ME was detected in human tooth pulp, orthodontic force caused a significant decrease in ME concentrations in the group of experimental teeth compared with controls, and ME levels of the first spring-attached tooth that was removed from each patient had a statistically significant inverse log-linear relationship to the amount of applied force. These data indicate that orthodontic force mobilizes at least one neuropeptidergic pathway in the human tooth pulp.

The identification of serum tuftsin by reverse-phase high-performance liquid chromatography and mass spectrometry

We describe for the first time a method for unambiguously identifying the phagocytic stimulating tetrapeptide tuftsin from trypsinized human serum. The method consists of separating serum tuftsin by reverse-phase (RP)-HPLC, collecting HPLC fractions corresponding to the synthetic tuftsin retention time, and then subjecting those fractions to mass spectrometry/mass spectrometry (MS/MS) analysis, which provides optimal molecular specificity to the measurement. Although quantification was not the goal, it was estimated that the amount of tuftsin found by RP-HPLC and MS/MS was in the hundreds of nanograms per milliliter.

Appraisal of narrow-bore (1 mm I.D.) high-performance liquid chromatography columns with view to the requirements of routine drug analysis

The potential advantages of using 1-mm bore high-performance liquid chromatography columns to replace conventional 4-5-mm bore columns for routine drug analysis have been considered in the light of various claims and counter-claims in the scientific literature. Experimental work has been conducted to measure the changes in mass sensitivity when using both UV and electrochemical detection. Further work has investigated the coupling of these narrow-bore columns in order to achieve high plate counts with particular reference to the influence of peak asymmetry. Finally the linking of the narrow-bore columns to a mass spectrometer with a moving-belt interface has been examined. All results are discussed with reference to the needs of the routine analyst.