Vol.3, No 2, 2005 pp. 151 - 155
UDC 577.11/543.393
CHARACTERIZATION OF
PESTICIDE-?-CYCLODEXTRIN
INCLUSION COMPLEXES IN AQUEOUS SOLUTION
G. Petrović, B. Stojčeva Radovanović, O. Jovanović
Faculty of Mathematics and Natural Sciences P.O. Box 224, 18001 Niš,
Serbia and Montenegro
Abstract. The solubility of four different pesticides:
"dimethoate",
"simazine", "linuron" and "thiram", very pour soluble or non soluble in
water, were measured in water and in aqueous solution of ?-cyclodextrin
by ultraviolet spectrophotometry. Standard water solutions of
pesticides
were prepared in the range of concentrations up to the maximum
solubility
of each pesticide in water. Concentrations of the pesticides were
determined
as absorbance on the absorption maximum. Obtained results show that the
aqueous solution of ?-cyclodextrin was a powerful solubilizer of
investigated
pesticides due to the formation of inclusion complexes. Effective
solubility
of some of the pesticides in aqueous ?-cyclodextrin solution were up to
three orders of magnitude higher than those in water. Thermodynamic
parameters
and complex stability constant of the obtained inclusion complexes were
determined by the calorimetric measurements.
Key words:
?-cyclodextrin,
complexes, pesticides, solubility.
KARAKTERIZACIJA INKLUZIONIH KOMPLEKSA
PESTICIDA
U VODENOM RASTVORU ?-CIKLODEKSTRINA
Promena rastvorljivosti u vodenom rastvoru ?-ciklodekstrina četiri
različita
pesticida: dimetoata, linurona, simazina i cirama; veoma slabo
rastvornih
ili nerastvornih u vodi, određivana je primenom UV spektrofotometrije.
Standardni rastvori pesticida pripremljeni su u opsegu koncentracija do
maksimalne rastvorljivosti svakog pesticida u vodi. Koncentracija
pesticida
određivana je merenjem apsorbancije na položaju apsorpcionog maksimuma.
Dobijeni rezultati ukazuju da se rastvorljivost ispitivanih pesticida u
vodenom rastvoru ?-ciklodekstrina u mnogome povećava građenjem
inkluzionih
kompleksa. Efektivna rastvorljivost nekih pesticida je porasla za tri
reda
veličine. Termodinamički parametri i konstante stabilnost nastalih
inkluzionih
kompleksa određivani su kalorimetrijskim merenjima.
