Novel Biomedical Sensors for Flow Injection Potentiometric Determination of Creatinine in Human Serum

Abstract

Coated-wire (CW) and tubular (Tu) type membrane sensors for creatinine are developed. These consist of creatinine tungstophosphate(CTP), creatinine molybdophosphate (CMP) and creatinine picrolonate (CPC) ion-pair complexes as electroactive materials dispersed in plasticized poly(vinyl chloride) matrix membranes. Electrochemical evaluation of these sensors under static (batch) mode of operation reveals near-Nernstian response with slopes of 62.9, 58.1, and 55.2 mV decade À1 over the concentration range 1 Â 10 À2 -5.0 Â 10 À6, 1 Â 10 À2 -7.5 Â 10 À5, and 1 Â 10. The lower detection limits are 0.39, 3.49, and 2.20 mg mL À1 creatinine with CTP, CMP and CPC membrane based sensors plasticized with o-NPOE, respectively. Tubular and coated wire CTP membrane sensors are incorporated in flow-through cells and used as detectors for flow injection analysis (FIA) of creatinine. The intrinsic characteristics of the detectors under hydrodynamic mode of operation in a low dispersion manifold are determined and compared with data obtained under static mode of operation. With 10 À2 mol L À1 phosphate buffer of pH 4.5 as a carrier solution, the tubular and coated wire CTP detectors exhibit rapid response of 58.9 and 50.7 mV decade À1 over the concentration range 1 Â 10 À2 -1 Â 10 À5 mol L À1 and detection limits of 0.39 mg mL À1 and 0.85 mg mL À1, respectively. Validation of the assay methods with the proposed sensors by measuring the lower detection limit, range, accuracy, precision, repeatability and between-day-variability reveals good performance characteristics confirming applicability for continuous determination of creatinine. The sensors are used for determining creatinine in human blood serum at an input rate of 40 samples per hour. No interferences are caused by creatine, most common anions, cations and organic species normally present in biological fluids. The results favorably compare with data obtained using the standard spectrophotometric method.

Metalloporphyrin-based acetate-selective electrodes as detectors for enzymatic acetylcholine determination in flow-injection analysis system

“…The ionophores dichloro(5,10,15,20-tetraphenylporphyrinato) zirconium(IV) (Zr(IV)[TPP]Cl 2 ) and dichloro [5,10,15,20-tetra(tertbutylphenyl)porphyrinato]zirconium(IV) (Zr(IV)[tTPP]Cl 2 ) were synthesized via a metallation of the corresponding free porphyrin (Porphyrin Products, Logan, UT) using ZrCl 4 (THF) complex (Fluka, Ronkonkoma, NY) [23]. Structures of these ionophores are shown in Fig.…”

“…Most popular potentiometric detectors in FIA systems are electrodes selective towards ammonium ions (based on nonactin as an ionophore), used for determination of clinically important analytes, such as urea or creatinine [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. However, electrodes selective towards other ions can also be employed as detectors in enzymatic analytical systems.…”

All-Solid-State Calcium Sensors Modified with Polypyrrol (PPY) and Graphene Oxide (GO) as Solid-Contact Ion-to-Electron Transducers

“…Of all the electrochemical techniques, potentiometry is probably the most preferred technique that fulfills all of these advantages. Potentiometric sensors "ion-selective electrodes" (ISEs), in a short time frame, can provide sensitive and reliable measurements for clinically critical analyses of small sample sizes [8][9][10]. In addition, the measuring devices for potentiometric sensors have the advantages of small size, simplicity of use, and provide fast and reliable responses.…”

Solid-State Membrane Sensors Based on Man-Tailored Biomimetic Receptors for Selective Recognition of Isoproturon and Diuron Herbicides

“…Among all electrochemical techniques, potential-based transduction “potentiometry” is potentially the most preferred technique. It presents good advantages such as quick and analysis, high sensitivity, cost-effectiveness, simplicity in use, and response reliability [ 19 , 20 , 21 ].…”