Mass spectra ethanol

Stephadiamine (16) was isolated as a minor component from the ethanolic extract of the whole plant of Stephania japonica collected in Taiwan (6). The IR spectrum of stephadiamine (16) exhibited bands at 3375 (NH2) and 1720 cm 1 (5-lactone), and the H-NMR spectrum (Table II) showed the presence of one JV-methyl and two methoxyl groups. Its mass spectrum revealed a base ion peak at m/z 243 of stephamiersine-type cleavage (Table V) (6). 

The antidepressant protriptyline (116) causes skin photosensitization in man. Jones and Sharpies irradiated an aqueous solution of the hydrochloride with a medium-pressure mercury lamp for 16 h and separated the products by preparative TLC. First formed was the epoxide (117) which photohydrated to the diol (118). Also isolated was the enol (119) [84], Earlier, Gasparro and Kochevar had shown that only the hydrochloride was photodegraded under nitrogen in water or ethanol. Three products were isolated and all lysed erythrocytes, but the structure of only one was suggested. This was a cyclobutyl dimer as shown by its mass spectrum and its photolysis back to protriptyline by light of 254 nm. Presumably, a [2 + 2] cycloaddition of the olefine bonds had occurred [85]. 

The mass spectrum shown is that for ethanol (CHjCHjOH). The 100-peak with the highest m/z ratio provides the gram formula mass of the organic compound. In the example, this appears at m/z = 46 and confirms the gram formula mass of ethanol as 46 g. 

Hi) Loss of the largest possible radical is most favoured. In the case of ethanol, loss of CH3- gives rise to the base peak in the mass spectrum at m/z 31. 

The addition of H2O2 to the mixtures containing 2-AF and peroxidase at pH 6.5 resulted in the rapid formation of a blue colour with an absorption maxima at 385 and 615 nm which reached a maximum in about 30 sec. The intensity of this colour was directly proportional to the enzyme and aminofluorene concentrations. One equivalent of H2O2 with respect to aminofluorene was required. The blue colour faded after this and became light brown after 5 mins. The blue colour disappeared upon extraction with ethyl acetate. The yellow extract was concentrated and applied to a TLC plate. The Rf of the various products is shown in Table III. Azofluorene was readily identified by its absorption spectra and mass spectrometry. The UV-visible absorption spectra had maxima in ethanol at 278 and 380 nm with shoulders at 362 and 396 nm. The mass spectrum showed a molecular ion at m/e 358.1463... 

If the abundances of the entire ethanol contracted spectrum are lowered — keeping their relative heights the same as in the reference spectrum — a point is reached where none of the unknown ions is of lower abundance than the corresponding ethanol peaks. In the example shown in Figure 7, this occurs when the mass 46 ions become the same height. If a measurement reproducibility of 20% is assumed, two other ions (m/e 43 and 45) are found to agree with the abundances required by the ethanol reference spectrum because they fall within the prescribed tolerance window. In this example, the mixture was about 50% ethanol the excess intensities at m/e 31 and 32 were due to methanol and the excess intensity at m/e 44 was due to the additional presence of CO2. 

Finally, the combined voltammetric and on-line differential electrochemical mass spectrometry measnrements allow a quantitative approach of the ethanol oxidation reaction, giving the partial current efficiency for each product, the total number of exchanged electrons and the global product yields of the reaction. But, it is first necessary to elucidate the reaction mechanism in order to propose a coherent analysis of the DBMS results. In the example exposed previously, it is necessary to state on the reaction products in order to evaluate the data relative to acetic acid production which cannot be directly detected by DBMS measurements. However, experiments carried out at high ethanol concentration (0.5 mol L" ) confirmed the presence of the ethyl acetate ester characterized by the presence of fragments at m/z = 61, 73 and 88 at ratios typical of the ethyl acetate mass spectrum. " This ethyl acetate ester is formed by the following chemical reaction between the electrochemically formed acetic acid and ethanol (Bq. 29) and confirms the formation of acetic acid. 

Figure 2. Electrospray ionization mass spectrum of octylphenoxy-poly(ethoxy) ethanol. Inset is the total ion chromatogram. Conditions are given in Experimental Details.

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