Determination of paraquat in raw and formalin-fixed tissues by Electron Spin Resonance (ESR) spectroscopy

Abstract

ESR method was applied to determine paraquat levels in fresh and formalin-fixed tissues. Paraquat was converted to paraquat radical by adding sodium dithionite to tissue homogenates and detected by ESR. Paraquat levels of more than 0.2 micrograms/ml homogenate could be quantified with 0.1 ml of the homogenate. The use of manganese ions for standardization of paraquat signal enabled much more accurate ESR measurements because this ion was quite stable and its signal did not overlap that of paraquat. Even with tissues fixed in formalin, tissues paraquat levels were measureable after removing formalin from the tissue extract. This fact was verified by studying two cases; the tissues were kept in formalin for 1.5 years in case 1 and for 6.5 years in case 2. In both cases, the paraquat contents in tissues were 0.02-0.08 micrograms/g. In this way ESR is one of the most suitable methods in determining low levels of paraquat in tissues even after they were preserved in formalin for a long time.

Levels of paraquat in fatal intoxications

“…Therefore, fatal levels of paraquat are suspected to be higher than those of previous reports [1,[3][4][5][6][7][8].…”

“…It has high toxicity since an oral dose of only 1~2 g is fatal to most adults [1,2] and there have been many reports about accidental and suicidal ingestion [1,[3][4][5][6][7][8][9]]. An assessment of the severity of paraquat poisoning using a toxicological index of paraquat to separate the survival and fatal cases has also been reported [10].…”

Glycyrrhizin and glycyrrhetinic acid determination from formalin-fixed tissue

“…These recovery rates are lower than those from fresh organs. Many investigators have also report-s. Tomono et al : GLY and GA detection from formalin-fixed tissue ed that lower concentrations of drugs and poisons were determined in formalin-fixed tissue or in formalin solution than in fresh organs (Kuo and Kuo 1988;Minakata et al 1989;Tomono et al 1989;Tsoukali-Papadopoulou 1987;Winek et al 1990). This could be due to residual formalin in the homogenate resulting in decreased GLY and GA concentrations in the formalin-fixed liver.…”

“…Several investigators have reported that they could detect poisons (Curry 1988, Kuo and Kuo 1988, Minakata et al 1989, Tomono et al 1989) in such tissue but there have been no reports concerning the detection of GLY and G A in formalin-fixed tissue.…”

Ανάλυση Ψυχοτρόπων Ουσιών Και Φαρμάκων Σε Μη Συμβατικά Βιολογικά Υλικά Και Μελέτη Της Σταθερότητας Αυτών Σε Μονιμοποιημένους Ιστούς

“…Ορισμένες μελέτες ασχολούνται με τον προσδιορισμό των ναρκωτικών και των φυτοφαρμάκων σε ταριχευμένα [86][87][88] ή μονιμοποιημένα σε φορμόλη όργανα και σε διαλύματα φορμόλης [89][90][91], ενώ άλλες μελέτες ασχολούνται με τη σταθερότητα των οπιούχων [92][93][94], της κοκαΐνης [95][96][97], των διεγερτικών αναλόγων της αμφεταμίνης [98][99][100][101], των βαρβιτουρικών [102][103][104], των βενζοδιαζεπινών [102,[105][106][107], των αντικαταθλιπτικών-αντισπασμωδικώναντιψυχωσικών [102,106,[108][109][110][111][112][113], λοιπών φαρμάκων [114][115][116], παρασιτοκτόνων [117][118][119], πτητικών ουσιών [102,120], βαρέων μετάλλων και ιχνοστοιχείων [121] σε περιβάλλον φορμόλης.…”