Integrated gold-disk microelectrode modified with iron(II)-phthalocyanine for nitric oxide detection in macrophages

An integrated gold-disk microelectrode (IGME) was fabricated and modified with Fe(II)-phthalocyanine (Fe(II)-PC) for NO detection in biological media. Microanalysis of NO using square wave anodic stripping voltammetry (SWASV) in 0.01 M HClO₄ was optimal at the initial potential of 0.1 V, frequency of 100 Hz, pulse amplitude of 25 mV, and a scan rate of 200 mV/s. When the electrode was modified with Fe(II)-phthalocyanines, the anodic peak current and sensitivity of NO were remarkably increased due to the catalytic oxidation of NO. The calibration curve had good linearity in the range from 3.6×10⁻⁵ to 7.2×10⁻⁷ M, and the detection limit was (5.7±1.2)×10⁻⁷ M. Fe(II)-phthalocyanine modified gold-disk microelectrode coated with Nafion was applied to determination of NO released from macrophage cell.     

Oxidative degradation of non-ionic surfactant (TritonX-100) by chromium(VI)

Degradation of polyoxyethylene chain of non-ionic surfactant (TritonX-100) by chromium(VI) has been studied spectrophotometrically under different experimental conditions. The reaction rate bears a first-order dependence on the [Cr(VI)] under pseudo-first-order conditions, [TritonX-100]  [Cr(VI)] in presence of 1.16 mol dm⁻³ perchloric acid. The observed rate constant (k_obs) was 3.3 × 10⁻⁴ to 3.5 × 10⁻⁴ s⁻¹ and the half-life (t_1/2) was 33–35 min for chromium(VI). The effects of total [TritonX-100] and [H⁺] on the reaction rate were determined. Reducing nature of non-ionic TritonX-100 surfactant is found to be due to the presence of –OH group in the polyoxyethylene chain. It was observed that monomeric and non-ionic micelles of TritonX-100 were oxidized by chromium(VI). When [TritonX-100] was less than its critical micelle concentration (cmc) the k_obs values increased from 0.76 × 10⁻⁴ to 1.5 × 10⁻⁴ s⁻¹. As the [TritonX-100] was greater than the cmc, the k_obs values increases from 2.1 × 10⁻⁴ to 8.2 × 10⁻⁴ s⁻¹ in presence of constant [HClO₄] (1.16 mol dm⁻³) at 40 °C. A comparison was made of the oxidative degradation rates of TritonX-100 with different metal ion oxidants. The order of the effectiveness of different oxidants was as follows: permanganate > diperiodatoargentate(III) > chromium(VI) > cerium(IV).     

Enhanced sensitivity for Cu(II) by a salicylidine-functionalized polysiloxane carbon paste electrode

A new approach for decreasing the detection limit for a copper(II) ion-selective electrode (ISE) is presented. The ISE is designed using salicylidine-functionalized polysiloxane in carbon paste. This work describes the attempts to develop the electrode and measurements of its characteristics. The new type of renewable three-dimensional chemically modified electrode could be used in a pH range of 2.3–5.4, and its detection limit is 2.7 × 10⁻⁸ mol L⁻¹ (1.2 μg L⁻¹). This sensor exhibits a good Nernstian slope of 29.4 ± 0.5 mV/decade in a wide linear concentration range of 2.3 × 10⁻⁷ to 1.0 × 10⁻³ mol L⁻¹ of Cu(II). It has a short response time (8 s) and noticeably high selectivity over other Cu(II) selective electrodes. Finally, it was satisfactorily used as an indicator electrode in complexometric titration with EDTA and determination of copper(II) in miscellaneous samples such as urine and various water samples.     

Voltammetric determination of N-acetylcysteine using a carbon paste electrode modified with copper(II) hexacyanoferrate(III)

The preparation and electrochemical characterization of a carbon paste electrode modified with copper(II) hexacyanoferrate(III) (CuHCF) as well as its behavior as electrocatalyst toward the oxidation of N-acetylcysteine were investigated. The electrochemical behavior of the modified electrode and the electrooxidation of N-acetylcysteine were explored using sweep linear voltammetry. The best voltammetric response was observed for a paste composition of 20% (w/w) copper(II) hexacyanoferrate(III) complex, acetate buffer solution at pH of 6.0 as the electrolyte and scan rate of 10 mV s^− 1. A linear voltammetric response for N-acetylcysteine was obtained in the concentration range from 1.2 × 10^− 4 to 8.3 × 10^− 4 mol L^− 1, with a detection limit of 6.3 × 10^− 5 mol L^− 1. The proposed electrode is useful for the quality control and routine analysis of N-acetylcysteine in pharmaceutical formulations.     

Novel heteroligand complexes of Co(II), Cu(II), Ni(II) and Mn(II) formed by 2,2′-dipyridyl or 1,10-phenanthroline and phosphortriamide ligands: Synthesis and structure

This paper presents examples of mixed-ligand Co(II), Cu(II), Ni(II) and Mn(II) complexes, with a distorted octahedral coordination geometry, with 2,2′-dipyridyl or 1,10-phenanthroline and phosphortriamide ligands. The complexes of the general type ML₂·Lig (where M = Co(II), Cu(II), Ni(II), Mn(II); L⁻ = {Cl₃C(O)NP(O)R₂}⁻ (R = NHBz, NHCH₂CHCH₂, NEt₂); Lig = 2,2′-dipyridyl or 1,10-phenanthroline) were synthesised and characterised by means of X-ray diffraction, IR and UV–Vis spectroscopy. The phosphortriamide ligands are coordinated via oxygen atoms of phosphoryl and carbonyl groups involved in six-membered metal cycles. The additional ligands 2,2′-dipyridyl or 1,10-phenanthroline are coordinated to the central atom, forming five-membered cycles.     

Voltammetric study of the interaction of lomefloxacin (LMF)–Mg(II) complex with DNA and its analytical application

The voltammetric behavior of the LMF-Mg(II) complex with DNA at a mercury electrode is reported for the first time. In NH₃–NH₄Cl buffer (pH=9.10), the adsorption phenomena of the LMF–Mg(II) complex were observed by linear sweep voltammetry. The mechanism of the electrode reaction was found to be a reduction of LMF in the complex, and the composition of the LMF–Mg(II) complex is 2:1. In the presence of calf thymus DNA (ctDNA), the peak current of LMF–Mg(II) complex decreased considerably, and a new well-defined adsorptive reduction peak appeared at −1.63 V (vs. SCE). The electrochemical kinetic parameters and the binding number of LMF–Mg(II) with ctDNA were also obtained. Moreover, the new peak currents of LMF–Mg(II)–DNA system increased linearly correlated to the concentration of DNA in the 4.00×10⁻⁷–2.60×10⁻⁶ g ml⁻¹ range when the concentrations of LMF–Mg(II) complex was fixed at 5.00×10⁻⁶ mol l⁻¹, with the detection limits of 2.33×10⁻⁷ g ml⁻¹. An electrostatic interaction was suggested by electrochemical method.     

Synthesis of new Cu(II), Ni(II) and Co(II) complexes with a bis-amide ligand functionalized with pyridine moieties: Spectral, magnetic and electrochemical studies

Three new copper(II), nickel(II) and cobalt (II) dinuclear complexes with a bis-amide ligand derived from tartaric acid have been prepared and characterized. For this purpose, the ligand (R,R)-(+)-di-N,N′-methylpyridino-tartramide (dmpt) was synthesized via the classical aminolysis of (R,R)-(+)-dimethyltartrate with pyridylmethylamine. The molecular structures of the complexes Na[Cu₂(dmptH₋₃)(CO₃)] · 8H₂O (1) and [Ni₂(dmptH₋₂)₂] · 9.75H₂O (2) were elucidated by X-ray diffraction, and the complex [Co₂(dmptH₋₃)(μ-OH)] · NaClO₄ · 5H₂O (3) by XAS. The crystal structure of (1) shows that the two metallic centres are in a square planar environment. Each copper(II) is bound to pyridyl and deprotonated amidic nitrogen atoms and to the oxygen atoms of hydroxyl and carbonato groups. In complex (2), both nickel atoms are in a distorted octahedral environment with an identical set of donors atoms, N₄O₂, coming from four nitrogen atoms of two pyridylmethylamido moieties and two oxygen donor atoms of alcohol groups. XAS analysis of complex (3) allows us to propose a CoN₂O₄ chromophore, with two nitrogen atoms coming from pyridyl and amidic groups and two bridged oxygen atoms from a deprotonated alcohol group and an hydroxyl group; the hexacoordination is achieved by two water molecules. The spectroscopic, electrochemical and magnetic properties of these complexes were investigated.     

Evaluation of a chloramine-T-selective electrode for catalytic titration of silver and mercury(II) based on iodide-catalyzed chloramine-T reactions

Semiautomatic methods are described for the catalytic titrimetric determination of microamounts of silver and mercury(II) using a chloramine-T-selective electrode as monitor. The methods are based on the inhibitory effect of Ag(I) and Hg(II) on the iodide-catalyzed chloramine-T-arsenite and chloramine-T-H₂O₂ reactions. Microamounts of silver in the range 0.2–200 μg (1 × 10⁻⁷−1 × 10⁻⁴ M) and of mercury(II) in the range 0.1–200 μg (2.5 × 10⁻⁸−5 × 10⁻⁵ M) were determined using the chloramine-T-As(III) indicator reaction. Mercury(II) in the range 4–2000 μg (1 × 10⁻⁶−5 × 10⁻⁴ M) was also determined using the chloramine-T-H₂O₂ indicator reaction. The accuracy and precision were in the range 0.1–1%.     

Investigation of the spectral properties of a squarylium near-infrared dye and its complexation with Fe(III) and Co(II) ions

The spectral features of the squarylium near-infrared (NIR) dye NN525 in different solutions and its complexation with several metal ions were investigated. The absorbance maximum of the dye is λ=663 nm in methanol. This value matches the output of a commercially available laser diode (650 nm), thus making use of such a source practical for excitation. The emission wavelength of the dye in methanol is λ_em=670 nm. The addition of either Fe(III) ion or Co(II) ion resulted in fluorescence quenching of the dye. The Stern–Volmer quenching constant, K_SV, was calculated from the Stern–Volmer plot to be K_SV=2.70×10⁷ M⁻¹ for Co(II) ion. The K_SV value for Fe(III) ion could not be established due to the non-linearity of the Stern–Volmer plot and the modified Stern–Volmer plot for this ion. The detection limit is 6.24×10⁻⁸ M for Fe(III) ion and 1.55×10⁻⁵ M for Co(III) ion. The molar ratio of the metal to the dye was established to be 1:1 for both metal ions. The stability constant, K_S, of the metal–dye complex was calculated to be 3.14×10⁶ M⁻¹ for the Fe–dye complex and 2.64×10⁵ M⁻¹ for the Co–dye complex.     

A new Tb-selective fluorescent sensor based on 2-(5-(dimethylamino)naphthalen-1-ylsulfonyl)-N-henylhydrazinecarbothioamide

A novel fluorescent chemosensor 2-(5-(dimethylamino)naphthalen-1-ylsulfonyl)-N-phenylhydrazinecarbothioamide (L) has been synthesized, which revealed an emission of 530 nm and when excited at 360 nm. The fluorescent probe undergoes a fluorescent emission intensity quenching upon binding to terbium ions in MeCN solution. The fluorescence quenching of L is attributed to the 1:1 complex formation between L and Tb(III) which has been utilized as the basis for the selective detection of Tb(III). The linear response range covers a concentration range of Tb(III) from 4.0 × 10⁻⁷ to 1.0 × 10⁻⁵ M and the detection limit is 1.4 × 10⁻⁷ M. The association constant of the 1:1 complex formation for L–Tb⁺³ was calculated to be 6.01 × 10⁶ M⁻¹, and the fluorescent probe exhibits high selectivity over other common metal ions mono-, di-, and trivalent cations indicate good selectivity for Tb(III) ions over a large number of interfering cations.     

Novel M(II)–Hg(II) coordination polymers generated from metal-containing building blocks M(2-pyrazinecarboxylate)2 · (H2O)2 (M=Cu, Ni, Co) and HgCl2

A new class of M(II)–Hg(II) (M=Cu(II), Co(II), Ni(II)) mixed-metal coordination polymers, Cu(2-pyrazinecarboxylate)₂HgCl₂ (4), [Co(2-pyrazinecarboxylate)₂(HgCl₂)₂] · 0.61H₂O (5) and [Ni(2-pyrazinecarboxylate)₂(HgCl₂)₂] · 0.77H₂O (6), have been prepared by self assembly of metal-containing building blocks, M(2-pyrazinecarboxylate)₂ · (H₂O)₂(M=Cu(II), Co(II), Ni(II)), with HgCl₂. Compounds 4–6 were characterized fully by IR, elemental analysis and single crystal X-ray diffraction. Compound 4 crystallized in the monoclinic space group C2/c, with a=17.916(5) Å, b=7.223(2) Å, c=13.335(4) Å, β=128.726(3)°, V=1346.2(6) ų, Z=4. It contains alternating Hg(II) and Cu(II) metal centers that are cross-linked by 2-pyrazinecarboxylate spacers and chlorine co-ligands to generate a unique three-dimensional Hg(II)–Cu(II) mixed metal framework. Compound 5 crystallized in the triclinic space group P , with a=6.3879(7) Å, b=6.6626(8) Å, c=13.2286(15) Å, α=96.339(2)°, β=91.590(2)°, γ=113.462(2)°, V=511.71(10) ų, Z=1. Compound 6 also crystallized in the triclinic space group P , with a=6.3543(8) Å, b=6.6194(8) Å, c=13.2801(16) Å, α=96.449(2)°, β=92.263(2)°, γ=113.541(2)°, V=506.67(11) ų, Z=1. Compounds 5 and 6 are isostructural and in the solid state the Hg(II)M(II)Hg(II) units are connected by Hg₂Cl₂ linkages to produce a novel M(II)–Hg(II) (M=Co(II), Ni(II)) zigzag mixed-metal chain, in which a new type of M–M′–M′–M array was observed. The metal containing building blocks, M(2-pyrazinecarboxylate)₂ · (H₂O)₂ (M=Cu(II), Co(II), Ni(II)), exhibit different connectivities to HgCl₂ depending on the metal cation contained within them.     

A novel fluorescent distinguished probe for Cr (VI) in aqueous solution

Salicylaldehyde rhodamine B hydrazone (SRBH) was developed as a new spectrofluorimetric probe for the selective and sensitive detection of CrO₄²⁻ in acidic conditions. The proposed method was based on the special oxidation reaction between non-fluorescent SRBH by potassium dichromate to produce a highly fluorescent rhodamine B, as a product. Under the optimum conditions described, the fluorescence enhancement at 591 nm was good linearly related to the concentration of CrO₄²⁻ from 1.0 × 10⁻⁸ to 3.0 × 10⁻⁷ M (0.42–12.6 ng mL⁻¹) with a correlation coefficient of R² = 0.9989 (n = 10) and a detection limit of 1.5 × 10⁻⁹ M (0.063 ng mL⁻¹). The relative standard deviation (R.S.D.) was 2.0% (n = 6). The proposed method was also successfully applied to the determination of chromium (VI) in drinking water, river water and synthetic samples.     

EPR and optical absorption studies of Cr ions in d-gluconic acid monohydrate

EPR studies are carried out on Cr³⁺ ions doped in d-gluconic acid monohydrate (C₆H₁₂O₇·H₂O) single crystals at 77 K. From the observed EPR spectra, the spin Hamiltonian parameters g, |D| and |E| are measured to be 1.9919, 349 (×10⁻⁴) cm⁻¹ and 113 (×10⁻⁴) cm⁻¹, respectively. The optical absorption of the crystal is also studied at room temperature. From the observed band positions, the cubic crystal field splitting parameter Dq (2052 cm⁻¹) and the Racah interelectronic repulsion parameter B (653 cm⁻¹) are evaluated. From the correlation of EPR and optical data the nature of bonding of Cr³⁺ ion with its ligands is discussed.     

A study of the spectrophotometric determination of traces of cadmium(II) and copper(II) with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol in the presence of polyglycol octylphenyl ether

A spectrophotometric study of the Cd(II) and Cu(II) complex of a new reagent, 2-(5-bromo-2-pyridylazo)-5-diethylamino phenol (5-Br-PADAP) in the presence of polyglycol octylphenyl ether (OP) is presented. A reddish binary complex is formed at pH 9 and shows maximal absorbance at 560 nm with molar absorptivity of 1.16 × 10⁵ · mol⁻¹ · cm⁻¹ liter (Cd), 1.5 × 10⁵ mol⁻¹ · cm⁻¹ · liter (Cu). Beer's law is followed over the range 0.0 to 20 μg cadmium(II) and 0.0–18 μg copper(II). The continuous variation method and molar ratio method showed that the metal ligand ratio is 1:2; ordinarily, most ions do not interfere with the determination and the method can be applied for direct spectrophotometric determination of cadmium(II) and copper(II) in actual samples and the results obtained are satisfactory.     

Trace determination of thiosulphate and thioglycolic acid using novel inhibitory kinetic spectrophotometric method

Sulphur containing compounds such as sodium thiosulphate (STS) and thioglycolic acid (TGA) inhibit the rate of cyanide substitution by nitroso-R-salt (NRS) in hexacyanoruthenate(II) catalysed by Hg(II) ions due to their strong binding tendencies with Hg(II) catalyst. This inhibitory effect of sodium thiosulphate and thioglycolic acid is used as the basis for their determination at micro levels. The reaction was followed spectrophotometrically at 525 nm (λ_max of [Ru(CN)₅NRS]³⁻ complex) under optimised reaction conditions at 8.75 × 10^− 5 M [Ru(CN)₆⁴⁻], 3.50 × 10^− 4 M [NRS], pH 7.00 ± 0.02, ionic strength (µ) 0.1 M (KCl) and temp 45.0 ±0.1 °C. The modified mechanistic scheme is proposed to understand the inhibition caused by sulphur containing compounds (STS and TGA) on Hg(II) catalysed substitution of cyanide by NRS in [Ru(CN)₆]⁴⁻. The range of analytical concentration of inhibitor depends upon two factors; the amount of Hg(II) catalyst present in the indicator reaction and the stability of the Hg(II)-inhibitor complex under consideration. Under optimum conditions STS and TGA have been determined in the range of 0.98-7.0 × 10^− 6 M and 0.30-7.0 × 10^− 6 M. The detection limits for STS and TGA were found to be 3.0 × 10^− 7 M and 1.0 × 10^− 7 M respectively.     

Synthesis, characterization, cytotoxic activity and DNA binding Ni(II) complex with the 6-hydroxy chromone-3-carbaldehyde thiosemicarbazone

A new ligand L, 6-hydroxy chromone-3-carbaldehyde thiosemicarbazone, and its Ni(II) complex have been synthesized and characterized. The crystal structure of Ni(II) complex was determined by single crystal X-ray diffraction. Ni(II) complex and ligand L were subjected to biological tests in vitro using THP-1, Raji and Hela cancer cell lines. Compared with the ligand, Ni(II) complex showed significant cytotoxic activity against these three cancer cell lines. The interactions of Ni(II) complex and ligand L with calf thymus DNA were then investigated by spectrometric titration, ethidium bromide displacement experiments and viscosity measurements methods. The experimental results indicated that Ni(II) complex bound to DNA by intercalative mode via the ligand L. The intrinsic binding constants of Ni(II) complex and ligand L with DNA were (1.10 ± 0.65) × 10⁶ M⁻¹ and (1.48 ± 0.57) × 10⁵ M⁻¹, respectively.     

Copper(II)-cetyltrimethylammonium chloride-chromal blue G ternary complex and its application to the spectrophotometric determination of copper(II)

A sensitive spectrophotometric method for the determination of copper(II) based on a ternary complex with chromal blue G, a triphenylmethane reagent in the presence of cetyltrimethylammonium chloride, is described. The sensitivity of color reaction between copper and chromal blue G has been greatly increased by the sensitizing action of cetyltrimethylammonium chloride, a cationic surfactant. The color development of the ternary complex can be utilized in the highly sensitive spectrophotometric determination of copper. The molar absorptivity of the binary complex between copper and chromal blue G ε_630nm = 9.56 × 10³liters · mol⁻¹ · cm⁻¹ is enchanced on ternary complex formation to ε_{542 nm} = 4.78 × 10⁴liters · mol⁻¹ · cm⁻¹. The ternary complex gave a maximal absorbance at 542 nm in the pH range 9.8–11. Beer's law is obeyed up to at least 1.2 ppm of copper. The maximal absorbance of the ternary complex was found to develop within 5 min and then it remains constant for several hours. The formation constant of the ternary complex is calculated to be 8.6 × 10¹⁰ under these conditions.     

Solid substrate-room temperature phosphorimetry for the determination of trace protein using ion association complex [Cu(BPY)2]·[(Fin)2] as a phosphorescent probe

Fluorescein (HFin) emitted strong and stable room temperature phosphorescence (RTP) on filter paper after set at 50 °C for 10 min using Li⁺ as the ion perturber. HFin existed as Fin⁻ when the pH value was in the range of 5.45–7.36. Fin⁻ could react with [Cu(BPY)₂]²⁺ (BPY: α,α-bipyridyl) to produce ion association complex [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻, which could enhance the RTP signal of Hfin. In the presence of bovine serum albumin (BSA), the –COOH group of Fin⁻ in the [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻ could react with the –NH₂ group of BSA to form the ion association complex [Cu(BPY)₂]²⁺·[(Fin-BSA)₂]²⁻, which contained –CO–NH– bond. This complex could sharply enhance the RTP signal of Hfin and the ΔI_p was directly proportional to the content of BSA. According to the facts above, a new solid substrate-room temperature phosphorimetry (SS-RTP) for the determination of trace protein had been established using the ion association complex [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻as a phosphorescent probe. This method had wide linear range (0.40 × 10⁻⁹–280 × 10⁻⁹ mg l⁻¹), high sensitivity (the detection limit (LD) was 1.4 × 10⁻¹⁰ mg l⁻¹), good precision (RSD: 3.4–4.9%) and high selectivity (the allowed concentration of coexistent ions or coexistent materials was high). It had been applied to the determination of the content of protein in 10 kinds of real samples, and the result agreed well with pyrocatechol violet-Mo (VI) method (P.V.M.M.), which indicated it had high accuracy. Meanwhile, reaction mechanism for the determination of trace protein with [Cu(BPY)₂]²⁺·[(Fin)₂]²⁻ phosphorescent probe was also discussed. The academic thought of this research could not only be used to develop many kinds of ion association complex phosphorescent probes, but also provided a new way to promote the sensitivity of SS-RTP.     

Comparative studies on hydrolysis of bis(p-nitrophenyl) phosphate catalyzed by short- and long-alkyl-multiamine metallomicelles

Four short- and long-alkyl-multiamine ligands L¹–L⁴ have been synthesized and characterized. The catalytic efficiency of complex CuL¹ and functional metallomicelles CuL²–CuL⁴ were comparatively investigated for the hydrolysis of bis(p-nitrophenyl) phosphate (BNPP) in buffered solution at 30 °C. The ternary kinetic model for metallomicellar catalysis was suggested to analyze the experimental data. The kinetic and thermodynamic parameters k^′_N, K_T and pK_a were obtained. The results indicated that the complexes with 1:1 ratio of ligands L²–L⁴ to copper(II) ion were the kinetic active catalysts, and the deprotonized Cu(II) complex formed by activated water molecule was the real active species for BNPP catalytic hydrolysis. The real rate constant of the reaction catalyzed by CuL¹–CuL⁴ was 4.00 × 10⁻⁶, 7.44 × 10⁻⁵, 1.42 × 10⁻⁴ and 4.10 × 10⁻⁴ s⁻¹, respectively. The effects of ligand and microenvironment on the hydrolytic reaction of BNPP have been discussed in detail.     

Binding of 6-propyl-2-thiouracil to human serum albumin destabilized by chemical denaturants

We compared the binding affinity of 6-propyl-2-thiouracil (PTU) with native and destabilized human serum albumin (HSA) as a model to assess the binding ability of albumin in patients suffering from chronic liver or renal diseases. Urea (U) and guanidine hydrochloride (Gu·HCl) at a concentration of 3.0 M were used as denaturation agents.Increasing the concentration of PTU from 0.8 × 10⁻⁵ to 1.20 × 10⁻⁴ M in the systems with HSA causes a decrease in fluorescence intensity of the protein excited with both 280 and 295 nm wavelengths. The results indicate that urea and Gu·HCl bind to the carbonyl group and then to the NH-group. To determine binding constants we used the Scatchard plots. The presence of two classes of HSA–PTU binding sites was observed. The binding constants (K_b) are equal to 1.99 × 10⁴ M⁻¹ and 1.50 × 10⁴ M⁻¹ at λ_ex = 280 nm, 5.20 × 10⁴ M⁻¹ and 1.65 × 10⁴ M⁻¹ at λ_ex = 295 nm. At λ_ex = 280 nm the number of drug molecules per protein molecule is a_I = 1.45 and a_II = 1.32 for I and II binding sites, respectively. At λ_ex = 295 nm they are a_I = 0.63 and a_II = 1.54 for the I and II binding sites.The estimation of the binding ability of changed albumin in the uremic and diabetic patients suffering from chronic liver or renal diseases is very important for safety and effective therapy.