Clarissa Frizzo

By Clarissa P. Frizzo, Aniele Z. Tier, Caroline R. Bender, Izabelle M. Gindri, Marcos A. Villetti, Nilo Zanatta, Helio G. Bonacorso and Marcos A.P. Martins

Part of the book: Ionic Liquids

By Clarissa Piccinin Frizzo, Bruno Luís Hennemann, Bruna Luisa Kuhn, Keli Maiara Wust, Alisson Vasques Paz, Marcos Antonio Pinto Martins, Nilo Zanatta and Hélio Gauze Bonacorso

In this chapter, we present a review on pyrazole fragmentation by gas chromatography coupled with mass spectrometry, in order to evaluate the substituent effect on pyrazole fragmentation. Our objective was to present a comprehensive study on the fragmentation pattern of substituted pyrazoles, contribute to the systematization of knowledge, and offer support to researchers in the characterization of pyrazoles via a comprehensive and versatile technique such as gas chromatography coupled with mass spectrometry. The pyrazole fragmentation showed two important processes: (i) expulsion of HCN from [M]+• and [M–H]+ and (ii) the loss of N2 from [M–H]+. Substituents such as D, Me, Br, Cl, and Ph did not influence these two processes; however, the presence of nitro, acetyl, oxime, diphenyl, or methyl and nitro in the ortho-position transforms the two processes into secondary fragmentation or results in their absence in the fragmentation of the said pyrazoles.

Part of the book: Gas Chromatography