Determination of chloride complex of Au(III) by capillary zone electrophoresis with direct UV detection

B.Baraj, A.Sastre, A.Merkoçi, M.Martinez. Journal of Chromatography A, 718, p. 227 (1995)

On the interference of Fe(III) in the spectrophotometric determination of Mn as MnO4

B.Baraj, Arben Merkoçi, F.Livardjani, A. Jaeger, M.J.F Leroy. Analysis, 22, p. 408 (1994)
Mn(II) was quantitatively preoxidized to  and then spectrophotometrically determined at 527 nm. The interference of Fe(III) was studied during this determination. The analysis of variance was used to test the significance of Fe(III) and H3PO4. The problem of the interference of Fe(III) in two materials, steel and ferrite (Fe, Mn,Zn)...

Potentiometric characterization of weak acids by multiple sample additions. I. Linear equations and intrinsic performance of the method

C.Maccà, Arben Merkoçi. Talanta, 41, p. 2033 (1994)
The suitability of linearized multiple sample-addition for the potenciometric characterization of monoprotic weak acids is examined. Linear equations for the separate or simultaneous determination of the aciduty constant of the sample concentration by treatment of experimental data are introduced. The intrinsic performance of the...

Determination of Ammonium ion in urine using an ammonium ion-selective electrode

Arben Merkoçi, V.Çoçoli, B.Baraj, S.Buzo. Acta Chimica Hungarica-Models in Chemistry, 130, p. 19 (1993)
The factorial design is used to study interferences of [K+] and pH during ammonium determi nation by NH4-ISE. It is concluded that as result of a negative pH-[K+] interactive interference the positive interference of [K+] may be diminished. The optimal pH for NH4+ determination is 7.4. A complete procedure is presented to diminish...

Determination of total and free calcium in serum by a macro measurement ion-selective electrode and a micro reference electrode

A.Merkoçi, B.Baraj, S.Buzo. Japanese Journal of Clinical Laboratory Automation, 17, p. 92 (1992)
A comparative study of various technics of calcium determination by ion selective electrode was carried out. Potentiometric titration of calcium ion with EDTA gives results for total calcium concentration ion serum. Directo method and multiple standard addition procedure can be used with the same accuracy for determination of free...