Spectrophotometric study of uranyl - orciprenaline complex and its application for orciprenaline determination in pharmaceutical preparations

ABSTRACT The composition and stability constant of UO2(II)-orciprenaline complex were determined using spectrophotometric methods and pH measurements. It was found that uranyl ion and orciprenaline form a 1:1 complex in the pH region 2.50 - 5.00, with apsorption maximum at 360.4 nm. The thermodynamic stabilityconstant at room temperature of the UO2(II)-orciprenaline complex is logβ01 = 7.52 and ∆G01= -42.9 kJ mol-1. A simple, accurate, sensitive and validated method was developed for the spectrophotometric determination of orciprenaline. A linear dependence at 360.4 nm of the absorbance on the concentration of orciprenaline was obtained in the range from 0.0020 mol L-1 to 0.0245 mol L-1 using a solution of 0.025 mol dm-3 UO2(NO3)2 at pH 3.90. The LOD was 0.00052 mol L-1 and LOQ was 0.00174 mol L-1. Recovery was 99.30% while the measurement error was 2.02 %

Spektrofotometrijsko ispitivanje kompleksa titanil oksalat-morin u 50% v/v etanolu

The composition of the titanyl oksalat-morin complex was determined by spectrophotometric method of variations of equimolar solutions and by the mole ratios method. The investigation of the composition and the concentration stability constant of the complex were carried out in a 50% V/V ethanol. It was found that titanyl oxalate ion and morin form 1:2 complex. The concentration stability constant of the complex, logβ2 was calculated for the pH=6,0 (5.83), pH=7,0 (6.40) andpH=8,0 (7.35).Sastav titanil oksalat-morin kompleksa određenje spektrofotometrijskom metodom varijacija ekvimolarnih rastvora i metodom molarnih odnosa. Ispitivanje sastava i određivanje koncentracionih konstanti stabilnosti ovog kompleksa vršeni su u 50% V/V etanolu. Nađeno je da se formira kompleks TiO(C2O4)22-: morin = 1:2. Određene su koncentracione konstante stabilnosti kompleksa: log β2 = 5,83 (pH = 6,0), log β2 =6,40 (pH = 7,0) i log β2 = 7,35 (pH =8,0)

Termodinamičke konstante stabilnosti kompleksa Fe(III)-jona sa orciprenalinom i fenilefrinom

The concentration stability constants of Fe(III)-orciprenaline complex and Fe(III)-phenylephrine complex were calculated for three different ionic strengths, by modificated Bjerrum's method. The values of thermodynamic stability constants are determined from curve log β = f (I1/2), as interception at ordinate. From the determined thermodynamic stability constants logβ10 =8,28 and logβ02 = 16,24 of the complexes investigated, the values of the ∆G10= - 46,87 kJ/mol and, AG° = -92,76 kJ/mol were calculated for Fe(III)-orciprenaline and Fe(III)- phenylephrine complexes respectively.Za komplekse Fe(III)-fenilefrin i Fe(III)-orciprenalin određene su vrednosti koncentracionih konstanti stabilnosti na tri jonske jačine (0,024; 0,050 0,075 mol/dm3). Na osnovu ovih vrednosti izračunate su termodinamičke konstante stabilnosti ovih kompleksa ekstrapolacijom dijagrama logβn=f(I) na vrednost I=0. Dobijena vrednost za kompleks Fe(III)-fenilefrin je logβ0 2 = 16,24, a za kompleks Fe(III)-orciprenalin ona iznosi logβ10= 8,28. Izračunate su promene standardne Gibbsove energije za reakciju stvaranja kompleksa: ∆G1°= -46,87 kJ/mol za Fe(III)- orciprenalin i ∆G°2 = -92,76 kJ/mol za Fe(III)-fenilefrin

Spektrofotometrijsko ispitivanje kompleksa između titanil oksalata i 3-hidroksiflavona u vodeno-etanolnoj smeši

It has been established, by the application of suitable spectrophotometric methods and pH-metric measurements, that titanyl oxalate anion and 3-hydroxyflavone (3HF) form a [TiO(C2O4)2(C15H9O3)2]4- complex. The investigation of the composition and the concentration stability constant of the complex were carried out in a 50 % aqueous ethanol solution at room temperature (20 °C), in the pH range from 1.9 to 9.0. The concentration stability constant of the complex, log β2, ranged from 16.65 at pH 5.0 to 13.96 at pH 7.0. The conditions for the spectrophotometric determination of 3HF by means of the complex formation were investigated in the concentration range from 2.5 x 10-5 to 3.0 x 10-4 mol dm-3 3HF.Korišćenjem pogodnih spektrofotometrijskih i pH-metrijskih metoda utvrđeno je da titanil oksalat i 3-hidroksiflavon (3HF) grade [TiO(C2O4)2(C15H9O3)2]4- kompleks. Ispitivanje sastava i određivanje koncentracionih konstanti stabilnosti ovog kompleksa vršeno je u 50 % etanolnom rastvoru, na sobnoj temperaturi (20 °C), u oblasti pH od 1,9 do 9,0. Izračunate vrednosti koncentracione konstante stabilnosti kompleksa, log β2, su u intervalu od 16,65 pri pH 5,0 do 13,96 na pH 7,0. Određeni su i uslovi za spektrofotometrijsko određivanje 3HF korišćenjem nagrađenog kompleksa u koncentracionom intervalu od 2,5 x 10-5 do 3,0 x 10-4 mol dm-3

Spectrofluorimetric and HPLC Determination of Morin in Human Serum

Morin is a flavonol antioxidant. In ethanol-water mixtures (70 wt% of ethanol) it reacts with Al(3+) to give Al(Morin)(2) in the pH range 3-6. The conditional stability constant of this complex at 298 K was found to be log beta(2) = 16.96 +/- 0.02 at pH 4.40. The complex shows strong fluorescence emission at 500 nm upon excitation at 410 nm. The fluorescence intensity is pH dependent with maximum emission at pH 4.40. Since the complexation reaction enhances the fluorescence of morin, this property was used for the determination of morin in human serum. A linear dependence of the intensity of fluorescence of the complex on the concentration of morin was obtained in morin concentration range from 1.5-30.5 ng mL(-1), relative standard error of measurements was 1.4%. The LOD was 0.02 ng mL(-1) while LOQ was 1.0 ng mL(-1). Serum concentration of morin was also determined using HPLC as a reference method. A C-18 Hypersil Gold AQ column was used with acetonitrile-0.1% v/v phosphoric acid (30:70% v/v) as the mobile phase at 1.0 mL min(-1) flow rate and UV detection at 250 nm. Acceptable relative standard errors (less than 5%) between determinations obtained by the two methods indicate that the fluorescence method is reliable

Fluorometrijsko određivanje hesperidina u sokovima od pomorandže prisutnim na tržištu Srbije

The spectrofluorometric method based on fluorescence ability of aluminium - hesperidin complex for the determination of hesperidin in orange juice is proposed. The linearity range of hesperidin in methanolicaqueous solution was 0.08 - 18.0 μg/mL with LOD and LOQ values as 0.023 μg/mL and 0.070 μg/mL, respectively, and recovery values in the range 97.8 - 99.7 %. Method was simplified by omitting any of surphactant agents usually applied in similar procedures, and successfully applied for the determination of hesperidin in orange juices commercially available on the Serbian market.U radu je predložena spektrofluorimetrijska metoda za određivanje sadržaja hesperidina u sokovima od pomorandže zasnovana na sposobnosti fluorescencije kompleksa aluminijum - hesperidin. Utvrđena je oblast linearnosti za određivanje hesperidina u metanolno-vodenim rastvora od 0.08 do 18.0 μg/mL, pri čemu je LOD= 0.023 μg/mL i LOQ= 0.070 μg/mL, a recovery vrednost 97.8 - 99.7 %. Metoda je pojednostavljena izostavljanjem često korišćenih površinski aktivnih materija koje se koriste u sličnim procedurama i uspešno je primenjena za određivanje sadržaja hesperidina u sokovima od pomorandže prisutnim na tržištu Srbije

Spectrophotometric investigation of the complexing reaction between rutin and titanyloxalate anion in 50% ethanol

In the present work, rutin (3,3',4',5,7-pentahydrohyflavone-3-rhamnoglucoside) was determinated via a complexing reaction with a titanyloxalate anion. K-2[TiO(C2O4)(2)] and rutin react in 50% ethanol forming a 1:2 complex in a pH range from 4.00 to 11.50, in which the TiO(C2O4)(2)(2-) ion is linked to rutin through the 4-carbonyl and 5-hydroxyl group. The thermodynamic stability constant log beta(2)(0) of the complex is determined to 10.80 at pH = 6.50. The change of the standard Gibbs free energy Delta G(0) amounts to -61 kJ . mol(-1), indicating that the process of complex formation is spontaneous. The optimal conditions for the spectrophotometric determination of microconcentrations of rutin are at pH = 6.40 and lambda = 430 nm, where the complex shows an absorption maximum with a molar absorption coefficient a(430) = (60+/-2) . 10(3) dm(3) . mol(-1) . cm(-1). The method is applied rutin determination from tablets