Chlorophyll aのMALDI 質量分析におけるマトリックスの影響
Matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) has been applied to the analysis of Chlorophyll a commercially available and separated with thin-layer chromatography from a maple leaf. The MALDI analysis of Chlorophyll a gave the intense peaks corresponding to molecular ion M+. and protonated analyte [M+H]+ when 5-amino-1-naphthol (5,1-ANL) was used as a matrix, while the use of carboxyl group containing matrices such as 2,5-dihydroxybenzoin acid (DHB), sinapinic acid (SA) and a-cyano-4-hydroxycinnamic acid (CHCA) gave the ion peaks of degraded products Pheophytin a (Mg taken off from Chlorophyll a) and Pheophorbide a (phytolchain taken off from Pheophytin a). The degradation of Chlorophyll a may occur by the presence of acidic functional groups in the matrix materials and solvents used. The mechanisms of the acid-induced degradation and photochemically-induced reduction of Chlorophyll a will be discussed on the basis of MALDI mass spectra obtained with several matrix and solvent conditions.