Separation and fragmentation study of isocoproporphyrin derivatives by UHPLC-ESI-exact mass MS/MS and identification of a new isocoproporphyrin sulfonic acid metabolite.

Abstract

Isocoproporphyrin and its derivatives are commonly used as biomarkers of porphyria cutanea tarda, heavy metal toxicity and hexachlorobenzene (HCB) intoxication in humans and animals. However, most are isobaric with other porphyrins and reference materials are unavailable commercially. The structural characterisation of these porphyrins is important but very little data is available. We report here the separation and characterisation of isocoproporphyrin, deethylisocoproporphyrin, hydroxyisocoproporphyrin and ketoisocoproporphyrin, isolated in the faeces of rats fed with a diet containing HCB, by ultra high performance liquid chromatography-exact mass tandem mass spectrometry (UHPLC-MS/MS). Furthermore, we report the identification and characterisation of a previously unreported porphyrin metabolite, isocoproporphyrin sulfonic acid isolated in the rat faeces. The measured mass-to-charge ratio (m/z) of the precursor ion was m/z 735.2338, corresponding to a molecular formula of C36H39N4O11S with an error of 0.3 ppm from the calculated m/z 735.2336. The MS/MS data was consistent with an isocoproporphyrin sulfonic acid structure, derived from dehydroisocoproporphyrinogen by sulfonation of the vinyl group. The metabolite was present in a greater abundance than other isocoproporphyrin derivatives and may be a more useful biomarker for HCB intoxication.

• Authors: Christopher M Benton, Chang Kee Lim, Caje Moniz, Sinéad L Baxter, Donald J L Jones
• Journal: Journal of mass spectrometry : JMS (J Mass Spectrom) Vol. 49 Issue 1 Pg. 80-5 (Jan 2014) ISSN: 1096-9888 [Electronic] England
• PMID: 24446266 (Publication Type: Journal Article)
• Copyright: Copyright © 2014 John Wiley & Sons, Ltd.

Chemical References

• Coproporphyrins
• Sulfonic Acids
• isocoproporphyrin
• Hexachlorobenzene

Topics

• Animals
• Chromatography, High Pressure Liquid (methods)
• Coproporphyrins (analysis, chemistry, metabolism)
• Feces (chemistry)
• Female
• Hexachlorobenzene
• Rats
• Rats, Sprague-Dawley
• Spectrometry, Mass, Electrospray Ionization (methods)
• Sulfonic Acids (analysis, chemistry, metabolism)
• Tandem Mass Spectrometry (methods)