Comparison of the sensitivity of mass spectrometry atmospheric pressure ionization techniques in the analysis of porphyrinoids

Abstract

The porphyrinoids chemistry is greatly dependent on the data obtained in mass spectrometry. For this reason, it is essential to determine the range of applicability of mass spectrometry ionization methods. In this study, the sensitivity of three different atmospheric pressure ionization techniques, electrospray ionization, atmospheric pressure chemical ionization and atmospheric pressure photoionization, was tested for several porphyrinods and their metallocomplexes. Electrospray ionization method was shown to be the best ionization technique because of its high sensitivity for derivatives of cyanocobalamin, free-base corroles and porphyrins. In the case of metallocorroles and metalloporphyrins, atmospheric pressure photoionization with dopant proved to be the most sensitive ionization method. It was also shown that for relatively acidic compounds, particularly for corroles, the negative ion mode provides better sensitivity than the positive ion mode. The results supply a lot of relevant information on the methodology of porphyrinoids analysis carried out by mass spectrometry. The information can be useful in designing future MS or liquid chromatography-MS experiments.

A rapid method to assess a broad inventory of organic species in marine sediments using ultra‐high resolution mass spectrometry

“…Thus, comparisons and discussions are all made on a relative monoisotopic intensity basis, although the linearity of APPI‐P ionization for some of the species reported herein, e.g. porphyrins, has been already reported . Although unambiguous molecular formula assignments are shown, the exact structural identity of the peaks cannot be confirmed without further experiments, such as tandem mass spectrometry (MS/MS).…”

“…porphyrins, has been already reported. [28] Although unambiguous molecular formula assignments are shown, the exact structural identity of the peaks cannot be confirmed without further experiments, such as tandem mass spectrometry (MS/MS). However, characteristic carbon number and DBE distributions can be used as a strong indication of the inferred molecular structures, particularly for the known and well-studied classes of biomarker species.…”

Recent developments in atmospheric pressure photoionization‐mass spectrometry

“…Negative‐ion APPI has been used for the LC‐MS analysis of phytoestrogenic isoflavones and lignans, which are secondary plant metabolites commonly encountered in the diet, from urine (Parker, Rybak, & Pfeiffer, ). In a comparison of ESI, APCI, and APPI in the analysis of porphyrinoids and their metal complexes, ESI was the most‐sensitive technique for free‐base porphyrins and corroles, and APPI for metalloporphyrins and copper complexes (Świder et al, ). For silver and chromium complexes APCI and ESI, respectively, were the best.…”

Adventures in corrole features by electrospray ionization mass spectrometry studies

“…[100][101][102] Besides ESI, other less common atmospheric pressure ionization techniques, such as atmospheric pressure photoionization (APPI) and atmospheric pressure chemical ionization (APCI), have been used, namely for metallochlorins, 88 metalloporphyrins 103 and corrole derivatives. 80,104 Notwithstanding its advantages and in contrast to the extensive use of MS techniques in porphyrin chemistry, the role of MS in corrole characterization is still very limited. Most of the reported papers on this topic describe the use of ESI-MS in the characterization of corroles, especially via accurate mass measurements, 58,89,[105][106][107][108][109][110][111][112][113][114][115] although a few studies of their gasphase chemistry, using this technique, have been published.…”