There is a consistent demand for developing highly sensitive, stable, cost-effective, and easy-to-fabricate creatinine sensors as creatinine is a reliable indicator of kidney and muscle-related disorders. Herein, we reported a highly sensitive and selective non-enzymatic electrochemical creatinine sensor via modifying poly(3,4 ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) coated indium tin oxide (ITO) substrate by zeolitic imidazolate framework-8 nanoparticles (ZIF-8 NPs). The topography, crystallinity, and composition of the sensing electrode were characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The peroxidase-like activity of ZIF-8 nanoparticles enabled it to detect creatinine forming a zinc-creatinine composite. The electrochemical behavior and sensing performance were evaluated by amperometric and impedimetric analysis. The sensor obtained a sufficiently low limit of detection (LOD) of 30 µM in a clinically acceptable linear range (0.05 mM–2.5 mM). The interference study demonstrated high selectivity of the sensor for creatinine concerning other similar biomolecules. The sensing performance of the creatinine sensor was verified in the actual human serum, which showed excellent recovery rates. Hence, the magnificent performance of ZIF-8 based non-enzymatic creatinine sensor validated it as a responsible entity for other complicated renal markers detection.

/pdf/zif-8-nanoparticles-based-electrochemical-sensor-for-non-1m84s4l0.pdf

ZIF-8 Nanoparticles Based Electrochemical Sensor for Non-Enzymatic Creatinine Detection

Titration potentiometry and spectrophotometry have both been used to determine stability constants for mixed complexes of Cu(II) with creatinine and EDTA. Stability constants of the ternary system were evaluated by a method suggested by the Irving-Rossotti procedure. Conditional constants were established as a function of pH; the maximum values of the conditional formation constants were found to be in agreement with the mixed-ligand complex formation constants in a given pH region. The mole fractions of mixed complexes were calculated using the formation constants. The stability constants of mixed-ligand complexes at 25°C are: log K| = 5.29, log K2 = 4.97, with ionic strength being kept constant at I = 0.1 with NaC104. Also, Cu(II)-I-glutamic acid-creatinine and Cu(II)-EDTA-creatinine complex formation, as examined by the spectrophotometric method, gave results that were in agreement with those of the Potentiometrie method. K e y w o r d s : creatinine, EDTA, 1-glutamic acid, copper(II) complexes, mixed complex, stability constants.

DETERMINATION OF STABILITY CONSTANTS OF MIXED LIGAND COMPLEXES OF Cu(II) WITH CREATININE AND ETHYLENEDIAMINE TETRAACETIC ACID OR I-GLUTAMIC ACID: POTENTIOMETRIC AND SPECTROPHOTOMETRIC METHODS

In this study, a potentiometric titration technique has been used to determine stability constants for the various complexes of Zn(II), Co(II), Cd(II) and Mn(II) with creatinine and two amino acids. Stability constants of ternary systems have been evaluated by the method suggested by Irving-Rossotti at 25°C and 0.11M ionic strength (kept constant with NaC104) in aqueous solution. In addition, the conditional con­ stants were calculated as a function of pH. The maximum values of the conditional formation constants were found to be in accordance with the mixed-ligand complex formation constants in a given pH region. In addition, the mole fractions of different species from mixed complexes were calculated by means of formation constants. The values of stability constants of mixed-ligand complexes at 25°C were calculated as follows: logK=3.20 for Zn(II)-L-cysteine-creatinine,logK1=4.24 and logK2=3.58 for Co(II)-L-cysteinecreatinine2, logK=3.22 for Cd(II) L-cysteine creatinine, logK=3.65 for Mn(II) L-cysteine creatinine and logK=5.34 for Co(II)-BDHL-cysteine-creatinine, logK=5.30 for Cd(II)-BDHL-cysteine-creatinine, logK,=5.35 and logK =3.93 for Zn(II) BDHL-cysteine creatinine^, logK,=5.40 and logK =3.49 for Mn(II) BDHL-cysteine creatinine,,

The determination of the stability constants of mixed Li- gand comlexes of creatinine-l-cysteine and creatinine-l- cysteine hydrochloride with Co(Ii), Cd(Ii), Zn(Ii), Mn(Ii): Using potentiometric method

Creatinine, being a natural metabolite of creatin, is a very important bioligand. Its importance in clinical chemistry is well recognized; its level in serum and urine is indicative of the renal function / l , 2/. The complexation ability of creatinine, due to the presence of several donor groups in its main tautomeric form, is well recognised and studies on the metal ion interactions with creatinine may be helpful in deciphering creatinine metabolic pathways /3, 4, 5, 6, 7/. The study of binary and ternary complexes of this ligand should be of interest due to the fact that creatinine metabolism might be connected with its complcxation to different metal ions 191. Five co-ordination modes have been established by X-ray crystallography:bidentate bridging through N(l)(r ing) and deprotonated exocyclic NH site 191, bidentate binding via N ( l ) (ring) and the exocyclic 0 ( C = 0 ) (11); monodentate binding through the N ( l ) (ring) site /11/; monodentate binding through the exocyclic 0 ( C = 0 ) /12/; and monodentate fashion through the deprotonated exocyclic NH group /10/.

Mixed-Ligand Complexes of Creatinine and L-Glutamic Acid With Co(II), Cu(II), Mn(II): Potentiometrie Studies

Bu calismada isoniazid ve iki aminoasitin bakir(II) ve cinko(II) metalleri ile olusturdugu karisik kompleks olusum dengeleri Irving Rossotti metodu ile potansiyometrik olarak tayin edildi. Uclu komplekslerin stabilite sabitleri Irving Rossotti yontemi ile 25±0.1 oC de ve iyonik kuvvet (0.11M) NaClO4 ile sabit tutularak sulu cozeltide incelendi. 25 oC de karisik ligand komplekslerin olusum sabitleri; Cu(II)-isoniazid-L-asparajin logK= 7.29; Zn(II)-isoniazid-L-asparajin logK= 4.09; Cu(II)-isoniazid-L-glutamik asit logK= 6.70; Zn(II)-isoniazid-L-glutamik asit logK= 6.30 olarak bulundu. Olusan komplekslerin kosullu olusum sabitleri pH’a bagli olarak hesaplandi ve belirli bir pH bolgesinde kosullu olusum sabitinin maksimum oldugu degerin deneysel olarak bulunan kararlilik sabiti ile uyum icinde oldugu gozlendi. Ayrica karisik kompleksten tureyen turlerin bagil bolluklari olusum sabitlerinden hesaplandi.

/pdf/ternary-complex-formation-of-isoniazid-with-some-transition-1utg5jd9h7.pdf

Ternary complex formation of isoniazid with some transition metals and amino acids

Creatinine is a physiological component of blood, brain and muscles and an important bioligand, which is the last product of the nitrogen metabolism in the vertebrates. In this study , the stability constants of binary complexes formed by creatinine with Zn(II) and Cd(II), and of the mixed-ligand complexes Zn(II)-creatinine1-asparagine and Zn(II) creatinine-l-glutamic acid were determined by the Calvin-Bjerrum and IrvingRossotti methods. The conditional formation constants and the formation pH ranges of complexes were determined. Relative abundance was plotted using conditional formation constants of the complexes and the steps of the complexes are shown in graphs. The composition of metal-creatinine complexes was determined as metal/ligand = 1: 1.

Zinc(II) and Cadmium(II) Binary Complexes with Creatinine and Their Mixed-Ligand Complexes with L-Asparagine or L-Glutamic Acid: Potentiometrie Studies

S. Karaderi

Papers

Zinc(II) and Cadmium(II) Binary Complexes with Creatinine and Their Mixed-Ligand Complexes with L-Asparagine or L-Glutamic Acid: Potentiometrie Studies