Abstract
Liquid ionization mass spectrometry was applied to distinguish between several types of fruits wines, such as grape wines (made from grapes), other fruits wines (made from fruits other than grapes) and grape wines with flavors. A microsyringe with a sharpened needle was used as a sample holder (Fig. 1), instead of a simple needle used previously.
Three μl of a sample wine is sucked into the microsyringe and then the syringe is installed in the ion source. One μl of the sample is pushed out to form a droplet on the needle tip and is ionized by metastable argon atoms at atmospheric pressure. When the needle is heated at a heater current of 0.5 A (ca. 40°C), the minor components of wines are observed most abundantly. A mass spectrum between m/z 10 and 400 is scanned in 3 seconds and 30 mass spectra are recorded for 5 minutes. An averaged mass spectrum of 30 scans and a subtracted mass spectrum are printed out by a microcomputor system. Seven characteristic Peaks (G) at m/z 88, 105, 133, 134, 168, 178, 179 to be indicative of grape wines, 6 characteristic peaks (F) at m/z 108, 113, 118, 149, 155, 159 to be indicative of fruit wines, and 5 specific peaks (U) at m/z 214, 228, 238, 246, 253 to be indicative of non-grape property were selected from mass spectra of about 30 bottles of wines. The number of the characteristic (G and F) and specific (U) peaks were counted for each wine and summarized as three dimentional graphic representation (Fig. 6). Results indicate that the method is useful for differentiating these types of wines. The method provides more informations and is simpler and quicker than other analytical methods.
