Acetone mass spectral peaks

Isopropyl- 2- H 7 hydrazine was prepared by hydrogenation of N -isopropylidene-tertiary-butylcarbazate with deuterium gas. In addition, this compound was prepared by reductive alkylation of the tertiary-butylcarbazate with sodium cyanoborodeuteride in acetone folj owed by mild acid hydrolysis. Deuteration of the isopropyl- 2- H 7 hydrazine in the above syntheses occurred specifically on the C-2 carbon atom as determined by NMR (lack of C-2 hydrogen septet at 3.25 ppm downfield from TMS) and El mass spectral analyses. The parent ion at m/e 75 indicated greater than 98% deuterium incorporation. The base peak at m/e 60 (M-15) with no contribution at m/e 59 indicated loss of a methyl group with no loss of deuterium. This interpretation of the fragmentation pattern was supported by the presence of a substantial metastable transition at m/e 48. 

Figure 5 Mass spectra can be considered as points or vectors in a multidimensional spectral space. For simplicity only two mass numbers (43, 58) have been selected in this example. A , abundance (peak height in %B) at mass m U, spectrum from unknown R1, reference spectrum of propanal R2, reference spectrum of acetone. Measures for spectral similarity are the Euclidean distance (d), the city block distance (A43 + Ajs) or the cosine of angle a (equivalent to S, in Eqn [2]).

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