Method for determining stable hydrogen isotope ratio of pure acetic acid methyl site

[0025] Example 1:

[0026] a) Take 2 commercially available glacial acetic acid as the research object, each measure 1mL, add 1g calcium carbonate and vortex for 2h;

[0027] b) Dry each supernatant in an oven, and take the powder for later use;

[0028] c) Convert the solid powder into hydrogen in the high-temperature cracking device, and set the temperature of the high-temperature cracking module to a constant temperature of 1420°C;

[0029] Confirm that the working environment, air tightness, and vacuum of the ion chamber of the stable isotope ratio mass spectrometer meet the requirements, and then inspect the instrument to determine H 2 In the precision and stability of δD, adjust the ion source parameter value if necessary;

[0030] The 0.1~0.3mg sample is introduced into the high-temperature cracking device and converted into hydrogen (H 2 ) And then determine the hydrogen isotope ratio (D / H, denoted as δD Measurement ), the results are shown in Table 1;

[0031] d) Select acetic a

[0039] Example 2:

[0040] The accuracy of the method is verified by the form of "adding standard recovery": the glacial acetic acid 2# sample of Example 1 was added to the acetic acid working standard WSD at the proportions of 80%, 60%, 40% and 20%. Since the acetic acid working standard WSD is known, and the acetic acid δD of glacial acetic acid 2# sample has been measured in Example 1. CH3 (‰) value, so the acetic acid δD of the simulated sample can be calculated CH3 The results are shown in Table 4; the simulated samples were measured according to the method in Example 1, and the results are shown in Table 4.

[0041] Table 4 Acetic acid δD in simulated samples CH3 value(‰)

[0042] Acetic acid working standard WSD addition ratio (%) 100806040200 Glacial acetic acid sample δD CH3 (‰)Predictive value

[0043] Comparing the two sets of data in Table 4, the t-test shows that there is no significant difference between the predicted value and the measured value of each sample, an