Quantitative determination of saccharide surfactants in protein samples by liquid chromatography coupled to electrospray ionization mass spectrometry.
A direct and highly selective method, combining liquid chromatography (LC) with electrospray ionization mass spectrometry (ESI-MS), has been developed for quantifying saccharide surfactants. Saccharide surfactants, such as n-octyl-beta-d-glucopyranoside (NOG), are widely used to solubilize or refold membrane-bound or lipophilic proteins. In the present study, we have developed an LC-MS method to quantify NOG in protein samples. Protein-bound NOG was completely dissociated from proteins by reversed-phase LC, allowing the total amount of saccharide surfactant in protein samples to be quantified by MS. A chemical analog of NOG was used as an internal standard for improving the reproducibility of the method. Linearity was found in the range of 10 microg/mL-1.0 mg/mL NOG concentrations. Seven major surfactant oligomeric ions were detected under the ionization conditions applied and their relative abundance was essentially unchanged over the range of 0.05-1.0 mg/mL NOG concentrations. Consequently, ions with characteristic mass-to-charge ratios could be used for quantification of NOG. Analytical accuracy of the method was examined by determining the amounts of NOG recovered from apolipoprotein A-I and myoglobin samples spiked with NOG.
Deng
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G
AstraZeneca Research & Development Boston, 35 Gatehouse Drive, Waltham, MA 02451, USA.
Chow
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Sanyal
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D000818:Animals; D016632:Apolipoprotein A-I / Q000378:metabolism; D002241:Carbohydrates / Q000737:chemistry*; D002417:Cattle; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D002853:Chromatography, Liquid; D004305:Dose-Response Relationship, Drug; D005960:Glucosides / Q000032:analysis; D006736:Horses; D007477:Ions; D013058:Mass Spectrometry; D008956:Models, Chemical; D009211:Myoglobin / Q000737:chemistry; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D013501:Surface-Active Agents / Q000737:chemistry*; D013997:Time Factors
D016632:Apolipoprotein A-I; D002241:Carbohydrates; D005960:Glucosides; D007477:Ions; D009211:Myoglobin; D013501:Surface-Active Agents; C018619:octyl-beta-D-glucoside