FENTIN COMPOUNDS JMPR 1972
Fentin compounds were considered at the Joint Meetings in 1965 and
1970. In the 1970 evaluation (FAO/WHO, 1971), further information was
required (1) on analytical methods capable of distinguishing between
fentin compounds and tricyclohexyltin hydroxide, and (2) on occurrence
of monophenyltin and diphenyltin compounds in the residues in celery.
FATE OF RESIDUES
A study (Freitag, 1972) on the terminal residues of 113Sn-labelled
fentin chloride in sugar beet leaves shows that triphenyltin is
converted via diphenyltin and monophenyltin to inorganic tin and that
the terminal residues consist mainly of triphenyltin and inorganic
tin. The proportion of diphenyltin and monophenyltin can be considered
insignificant in the terminal residues.
METHODS OF RESIDUE ANALYSIS
A colorimetric method (Bürger, 1961) is available which allows the
determination of triphenyltin in the presence of trihexyltin in the
It has been demonstrated that triphenyltin in sugar beet leaves is
degraded via diphenyltin and monophenyltin to inorganic tin, and the
amounts of diphenyltin and monophenyltin are insignificant in the
terminal residues. The Joint Meeting considered that this information
applies also to the residues of fentin compounds in celery.
A colorimetric method is available which is suitable for determination
of triphenyltin in the presence of trihexyltin in the residues.
The further information required by the 1970 meeting and made
available to the 1972 Meeting is considered satisfactory.
In addition to the recommendations for tolerances made by the 1970
Meeting, the following recommendations are made for those crops on
which fentin compounds are used and where residues have been found to
be below the limit of determination by the analytical methods.
Pecans (shelled) 0.05*
Rice (in husk), cocoa beans,
coffee (raw beans) 0.1*
* at or about the limit of determination
FURTHER WORK OR INFORMATION
Bürger, K. (1961) Zur Analytik von Organozinnverbindungen, Z.
Lebensmittel-Unters.u.-Forschung, 114: 1-10.
FAO/WHO (1971) 1970 evaluations of some pesticide residues in food
FAO/AGP/1970/M/12/1; WHO/Food Add./71.42.
Freitag, K.-D. (1972) Metabolismus und Rückstandsanalytik des
Triphenylzinnchlorides. Dissertation. Naturwissenschaftliche Fakultät
der Johannes-Gutenberg - Universität in Mainz.
1970 evaluations of some pesticide residues in food. Fentin Compounds.
p.350, line 15, for Hoechst 1967 read Hoechst 1968r. p.360,
after Hoechst 1968g entry add Hoechst Report 43IIIA-45IIIA-46IIA-
51IIA, dated 5-9-1968. (unpublished)