Mariela Stefanova Kamburova

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The extraction of chromium (VI) with iodnitrotetrazolium chloride (INT) was studied spectrophotometrically. The basic spectrophotometric characteristics of the ion associated formed were determined. Using different methods it was found that the ratio between chromium and INT was 1:1. The molar absorptivity of the associate is (250) = (3.70 +/- 0.08) x 10(4)(More)
* corresponding author. e-mail: The interaction of Mo(VI) and tetrazolium violet (TV) has been examined. The ion-associate formed is extracted into 1,2-dichloroethane. The tetrazolium violet : molybdenum(VI) : 3,4,5-trihydroxybenzoic acid ratio (R) is 2 : 1 : 2. The optimum conditions have been established. Beer’s law is obeyed in(More)
The interaction of Cr(VI) and the thiazine dye Methylene Blue has been examined. The ion-associate formed is extractable into 1,2-dichlorethane. The optimum conditions have been established, and values obtained for the conditional extraction constant K'(ex), distribution constant K'(D) and association constant beta'. A sensitive and selective method for(More)
Level of prematurity is an objective criterion for determining the health welfare of the population. Several family background factors of the mother increases the risk of preterm birth child - family status, unwanted pregnancy, etc. Pregnancy among unmarried women and unwanted pregnancy are associated with a higher risk of giving premature baby. Aim of this(More)
INTRODUCTION Many studies confirmed the lower risk of prematurity among working women and established a link between heavy physical work and the prematurity. The aim of the study is to establish the association between unemployment and the heavy physical work of the mother during pregnancy and the birth of a premature baby. MATERIAL AND METHODS In 2011(More)
Optimum conditions for complexation in the systems triphenyl-tetrazolium chloride-iodate-iodide-dichlorethane and triphenyltetrazolium chloride-periodate-iodide-dichlorethane were found. The molar absorptivity of the complex was 7.48 x 10(4) 1. mole(-1). cm(-1) for the iodate, and 9.09 x 10(4)1. mole(-1) cm(-1) for the periodate. Beer's law is adhered to in(More)
The formation of the acidocomplex of mercury(II) with triphenyl-tetrazolium chloride is studied spectrophotometrically in water-organic media. The composition of the complex is established as TTC:Hg:I = 1:1:1. The molar absorptivity (255) = (6.45 +/- 0.12) x 10(4) 1 mole(-1). cm(-1) is determined. The selectivity of the reaction is studied and the method(More)
The interaction of Mn(VII) and the Neotetrazolium chloride has been examined. The ion-associate formed is extracted into 1,2di-chloroethane. The optimum conditions have been established. The molar absorptivity of the complex is (9.1+/-0.08)x10(5) l mol(-1) cm(-1). The sensitivity of the method is 6.04x1010(-5) mug cm(-2). It is possible to extract and(More)