Nuri Yildirim

A new approach to separation and pre-concentration of some trace metals with co-precipitation method using a triazole

A new co-precipitation method was developed to separate and pre-concentrate Fe(3+), Cu(2+), Cr(3+), Zn(2+), and Pb(2+) ions using an organic co-precipitant, 3-benzyl-4-p-nitrobenzylidenamino-4,5-dihydro-1,2,4-triazole-5-on (BPNBAT) without adding any carrier element, following flame atomic absorption spectrometric (FAAS) determinations. Effect of some analytical conditions, such as pH of the solution, quantity of the co-precipitant, standing time, centrifugation rate and time, sample volume, and interference of concomitant ions were investigated over the recovery yields of the metal ions. The recoveries of the analyte ions were in the range of 95-102%. The detection limits, corresponding to three times the standard deviation of the blank, were found to be in the range of 0.3-2.0 microg L(-1). The precision of the method, evaluated as the relative standard deviation (R.S.D.) obtained after analyzing a series of 10 replicates, was between 1.6% and 6.0% for the trace metal ions. The method was validated by analyzing two certified reference materials and spiked addition. The proposed procedure was applied for the trace metal ions in some environmental samples.

Carrier element-free coprecipitation with 3-phenly-4-o-hydroxybenzylidenamino-4,5-dihydro-1,2,4-triazole-5-one for separation/preconcentration of Cr(III), Fe(III), Pb(II) and Zn(II) from aqueous solutions.

A separation/preconcentration procedure, based on the coprecipitation of Cr(3+), Fe(3+), Pb(2+) and Zn(2+) ions using a new organic coprecipitant, 3-phenly-4-o-hydroxybenzylidenamino-4,5-dihydro-1,2,4-triazole-5-one (POHBAT) without adding any carrier element has been developed. The method, thus, has been called carrier element-free coprecipitation (CEFC). The resultant concentrated elements were determined by flame atomic absorption spectrometric determinations. The influences of some analytical parameters including pH of the solution, amount of the coprecipitant, standing time, centrifugation rate and time, sample volume and diverse ions were investigated on the quantitative recoveries of analyte ions. The validation of the present preconcentration procedure was performed by the analysis of two certified reference materials. The recoveries of understudy analytes were found in the range of 93-98%, while the detection limits were calculated in the range of 0.3-2.0 microg L(-1). The precision of the method evaluated as relative standard deviation (R.S.D.), was in the range of 3-7% depend on the analytes. The proposed method was successfully applied to environmental samples for the determination of the analytes.

SYNTHESIS OF SOME BENZYLIDENAMINO COMPOUNDS

SummaryReactions of 3-substituted-4-amino-4,5-dihydro-1,2,4-triazol-5-ones with salicylaldehyde,o-chlorobenzaldehyde andp-tolualdehyde were studied, and 14 new benzylidenamino compounds were obtained.ZusammenfassungDie Reaktionen von 3-substituierten 4-Amino-4,5-dihydro-1,2,4-triazol-5-onen mit Salicylaldehyd,o-Chlorobenzaldehyd undp-Tolualdehyd wurden untersucht und 14 Benzylidenaminoverbindungen dargestellt.

Triterpenes from Campanula lactiflora

One new triterpene compound, 3β-acetoxylup-20(30)-en-29-al (1) and two known 3-acetylptiloepoxide (2) and 3β-acetoxylup-20(29)-ene (3) were isolated for the first time from the leaves of Campanula lactiflora and their structures were deduced by high field 1D and 2D 400 MHz NMR, EI-MS and (+) LC-MS/MS spectra.

Use of ester formylhydrazones for the synthesis of 1,2,4-triazole and 1,3,4-oxadiazole derivatives

A series of ester formylhydrazones were synthesised by the reaction of alkyl imidate hydrochlorides with formyl-hydrazine. Treatment of the ester formylhydrazones with acetic acid hydrazide, isonicotinic acid hydrazide, nicotinic acid hydrazide, and 4-hydroxybenzhydrazide resulted in the formation of either 4-acylamino-4H-1,2,4-triazoles or 2,5-disubstituted 1,3,4-oxadiazoles. 3-Alkyl-4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones were synthesised by the reaction of the ester formylhydrazones with carbohydrazide. Some arylidenamino compounds were synthesised by the reaction of 4-amino-4,5-dihydro-1H-1,2,4-triazol-5-ones with several aldehydes. These compounds were characterised by elemental analyses, IR, 1H NMR, and UV spectral techniques.