Apparatus and method for processing mass spectrum

A mass spectrum processing method comprising the steps of:

• computing a first degree of similarity between a first representative value array that represents a target mass spectrum obtained by mass spectrometry of a sample and a first corresponding value array that is selected from a standard mass spectrum in a library according to a corresponding relationship with the first representative value array;
• computing a second degree of similarity between a second representative value array that represents the standard mass spectrum and a second corresponding value array that is selected from the target mass spectrum according to a corresponding relationship with the second representative value array;
• judging that the target mass spectrum is a composite mass spectrum derived from a plurality of compounds, or providing information indicating the possibility that the target mass spectrum is the composite mass spectrum, based on the first degree of similarity and the second degree of similarity, wherein the first degree of similarity is a degree of forward similarity that has a characteristic of being lower as a likelihood that the target mass spectrum is a composite mass spectrum derived from a plurality of compounds is higher, and wherein the second degree of similarity is a degree of reverse similarity that has a characteristic of being higher as a likelihood that the target mass spectrum includes the standard mass spectrum is higher;
• performing a library search based on the target mass spectrum and generate a list of candidate compounds;
• identifying a group of candidate compounds from the list of candidate compounds by narrowing the list of candidate compounds based only on a plurality of second degrees of similarity corresponding to a plurality of candidate compounds constituting the list of candidate compounds,
• calculating, for each candidate compound in the group of candidate compounds, a difference between the first degree of similarity and the second degree of similarity as a difference between the degrees of similarity, and
• judging that the target mass spectrum is in the composite state based on a plurality of differences between the degrees of similarity corresponding to a plurality of candidate compounds constituting the group of candidate compounds.

A non-transitory storage medium storing a program to be executed in an information processing device, the program comprising:

• a function of computing a first degree of similarity between a first representative value array that represents a target mass spectrum obtained by mass spectrometry of a sample and a first corresponding value array that is selected from a standard mass spectrum in a library according to a corresponding relationship with the first representative value array;
• a function of computing a second degree of similarity between a second representative value array that represents the standard mass spectrum and a second corresponding value array that is selected from the target mass spectrum according to a corresponding relationship with the second representative value array;
• and
• a function of judging that the target mass spectrum is a composite mass spectrum derived from a plurality of compounds, or providing information indicating the possibility that the target mass spectrum is the composite mass spectrum, based on the first degree of similarity and the second degree of similarity, wherein the first degree of similarity is a degree of forward similarity that has a characteristic of being lower as a likelihood that the target mass spectrum is a composite mass spectrum derived from a plurality of compounds is higher, and wherein the second degree of similarity is a degree of reverse similarity that has a characteristic of being higher as a likelihood that the target mass spectrum includes the standard mass spectrum is higher;
• a function of performing a library search based on the target mass spectrum and generate a list of candidate compounds;
• a function of identifying a group of candidate compounds from the list of candidate compounds by narrowing the list of candidate compounds based only on a plurality of second degrees of similarity corresponding to a plurality of candidate compounds constituting the list of candidate compounds,
• a function of calculating, for each candidate compound in the group of candidate compounds, a difference between the first degree of similarity and the second degree of similarity as a difference between the degrees of similarity, and
• a function of judging that the target mass spectrum is in the composite state based on a plurality of differences between the degrees of similarity corresponding to a plurality of candidate compounds constituting the group of candidate compounds.