scholarly journals Highly Stable Potentiometric (Bio)Sensor for Urea and Urease Activity Determination

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 898
Author(s):  
Marcin Urbanowicz ◽  
Kamila Sadowska ◽  
Agnieszka Paziewska-Nowak ◽  
Anna Sołdatowska ◽  
Dorota G. Pijanowska
Keyword(s):  
Urease Activity ◽  
Enzymatic Reaction ◽  
Human Saliva ◽  
Ammonium Ion ◽  
Good Time ◽  
Activity Determination ◽  
Spectrophotometric Methods ◽  
Selective Membrane ◽  
Good Potential

There is growing interest for bioanalytical tools that might be designed for a specific user, primarily for research purposes. In this perspective, a new, highly stable potentiometric sensor based on glassy carbon/polyazulene/NH4+-selective membrane was developed and utilized for urease activity determination. Urease–urea interaction studies were carried out and the Michaelis–Menten constant was established for this enzymatic reaction. Biofunctionalization of the ammonium ion-selective sensor with urease lead to urea biosensor with remarkably good potential stability (drift coefficient ~0.9 mV/h) and short response time (t95% = 36 s). The prepared biosensor showed the Nernstian response (S = 52.4 ± 0.7 mV/dec) in the urea concentration range from 0.01 to 20 mM, stable for the experimental time of 60 days. In addition, some insights into electrical properties of the ion-to-electron transducing layer resulting from impedance spectroscopy measurements are presented. Based on the RCQ equivalent circuits comparison, it can be drawn that the polyazulene (PAz) layer shows the least capacitive behavior, which might result in good time stability of the sensor in respect to response as well as potential E0. Both the polyazulene-based solid-contact ion selective electrodes and urea biosensors were successfully used in trial studies for determination of ammonium ion and urea in human saliva samples. The accuracy of ammonium ion and urea levels determination by potentiometric method was confirmed by two reference spectrophotometric methods.

scholarly journals Determination of lysosomal exoglycosidases in human saliva.

2014 ◽  
Vol 61 (1) ◽  
Author(s):  
Sylwia Chojnowska ◽  
Anna Zalewska ◽  
Małgorzata Knaś ◽  
Napoleon Waszkiewicz ◽  
Danuta Waszkiel ◽  
...  
Keyword(s):  
Synovial Fluid ◽  
Clinical Diagnosis ◽  
Human Saliva ◽  
Variation Coefficient ◽  
Optimal Conditions ◽  
Oral Diseases ◽  
Activity Determination ◽  
Non Invasive

Currently we observe a growing interest in human saliva as a non-invasive material for diagnosis and monitoring of general and oral diseases. The aim of our study was adaptation of the Marciniak et al. (Marciniak J, Zalewska A, Popko J, Zwierz K, 2006, Clin Chem Lab Med 44: 933-937) method for determination of HEX and GLU activity in synovial fluid, and for determination of: HEX and GLU, as well as MAN, GAL, and FUC activity in human saliva. Under optimal conditions, 10 μl of saliva for HEX, and 30 μl for GLU, MAN, GAL and FUC, were sufficient for determination of human salivary exoglycosidases activity with variation coefficient ranging from 0.89 for GLU to 0.99 for GAL. The adapted method for exoglycosidases activity determination in human saliva is sufficiently sensitive and precise to use in clinical diagnosis.

scholarly journals A miniaturized solid-contact potentiometric multisensor platform for determination of ionic profiles in human saliva

2019 ◽  
Vol 23 (12) ◽  
pp. 3299-3308 ◽  
Author(s):  
Marcin Urbanowicz ◽  
Dorota G. Pijanowska ◽  
Artur Jasiński ◽  
Marcin Ekman ◽  
Maria K. Bocheńska
Keyword(s):  
Biomedical Research ◽  
Electrode Surface ◽  
Intermediate Layer ◽  
Gold Electrode ◽  
Human Saliva ◽  
Ion Selective Electrodes ◽  
Solid Contact ◽  
Selective Membrane ◽  
Metrological Parameters

Abstract This paper describes a miniaturized multisensor platform (MP-ISES) consisting of electrodes: a reference one (RE) and ion-selective electrodes (ISEs) for monitoring Na+, K+, Ca2+, Mg2+, Cl−, and SCN− ions and pH in human saliva. Gold electrode surface was modified by deposition of two layers: electrosynthesized PEDOT:PSS forming an intermediate layer, and ion-selective membrane. The developed ISEs were characterized by a wide linear range and sensitivity consistent with the Nernst model. The entire MP-ISEs are characterized by satisfactory metrological parameters demonstrating their applicability in biomedical research, in particular in measurements concerning determination of ionic profiles of saliva. Saliva samples of 18 volunteers aged from 20 to 26 participating in a month experiment had been daily collected and investigated using the MP-ISEs assigned individually to each person. Personalized profiles of ions (ionograms) in saliva, such as Na+, K+, Ca2+, Mg2+, Cl−, SCN−, and H+, were obtained.

scholarly journals Potentiometric Solid-Contact Ion-Selective Electrode for Determination of Thiocyanate in Human Saliva

Sensors ◽  
2020 ◽  
Vol 20 (10) ◽  
pp. 2817
Author(s):  
Marcin Urbanowicz ◽  
Kamila Sadowska ◽  
Dorota G. Pijanowska ◽  
Radosław Pomećko ◽  
Maria Bocheńska
Keyword(s):  
Daily Basis ◽  
Human Saliva ◽  
Ion Selective Electrode ◽  
Potentiometric Sensors ◽  
Membrane Composition ◽  
Solid Contact ◽  
Selective Electrode ◽  
Selective Membrane ◽  
Selection Of

A new solid-contact potentiometric ion-selective electrode for the determination of SCN− (SCN-ISE) has been described. Synthesized phosphonium derivative of calix[4]arene was used as a charged ionophore. The research included selection of the ion-selective membrane composition, determination of the ISEs metrological parameters and SCN-ISE application for thiocyanate determination in human saliva. Preparation of the ISEs included selection of a plasticizer for the ion-selective membrane composition and type of the electrode material. The study was carried out using ISE with liquid internal electrolyte (LE-ISE) and solid-contact electrodes made of glassy carbon (GC-ISE) and gold rods (Au-ISE). The best parameters were found for GC sensors for which the ion-selective membrane contained chloroparaffin as a plasticizer (S = 59.9 mV/dec, LOD = 1.6 × 10−6 M). The study of potentiometric selectivity coefficients has shown that the thiocyanate-selective sensor could be applied in biomedical research for determination of SCN− concentration in human saliva. The accuracy of the SCN− determination was verified by testing 59 samples of volunteers’ saliva by potentiometric sensors and UV-Vis spectrophotometry as a reference technique. Moreover, SCN− concentrations in the smokers’ and non-smokers’ saliva were compared. In order to investigate the influence of various factors (sex, health status, taken medications) on the thiocyanate level in the saliva, more extensive studies on a group of 100 volunteers were carried out. Additionally, for a group of 18 volunteers, individual profiles of SCN− concentration in saliva measured on a daily basis for over a month were collected.

ISOLATION AND ACTIVITY DETERMINATION OF ENZYMES SECRETED BY ASPERGILLUS NIGER

2019 ◽  
Vol 2 (1) ◽  
pp. 67-74
Author(s):  
Oleen Machona ◽  
Ronald Mlambo ◽  
Tafadzwa Zharare ◽  
Rumbidzai Mangoyi
Keyword(s):  
Aspergillus Niger ◽  
Activity Determination

Colorimetric Determination of Amoxicillin in Pure and some Pharmaceutical Formulations Via Reaction with Potassium Permanganate as Oxidant Reagent

2019 ◽  
Vol 10 (02) ◽  
Author(s):  
Abbas Shebeeb Al-kadumi ◽  
Sahar Rihan Fadhel ◽  
Mohammed Abdullah Ahmed ◽  
Luma Amer Musa
Keyword(s):  
Potassium Permanganate ◽  
Pharmaceutical Preparations ◽  
Pharmaceutical Formulations ◽  
Atomic Emission ◽  
Basic Medium ◽  
Photometric Method ◽  
Colorimetric Determination ◽  
Spectrophotometric Methods ◽  
Label Claim

We proposed two simple, rapid, and convenient spectrophotometric methods are described for the determination of Amoxicillin in bulk and its pharmaceutical preparations. They are based on the measurement of the flame atomic emission of potassium ion (in first method) and colorimetric determination of the green colored solution for manganite ion at 610 nm formed after reaction of Amoxicillin with potassium permanganate as oxidant agent (in the second method) in basic medium. The working conditions of the methods were investigated and optimized. Beer's law plot showed a good correlation in the concentration range of 5-45 μg/ml. The detection limits and relative standared deviations were (2.573, 2.814 μg/ml) (2.137, 2.498) for the flame emission photometric method and (1.844, 2.016 μg/ml) (1.645,1.932) for colorimetric methods for capsules and suspensions respectively. The methods were successfully applied to the determination of Amoxicillin in capsules and suspensions, and the obtained results were in good agreement with the label claim. No interference was observed from the commonly encountered additives and expectancies.

Determination of the prevalence of helicobacter pylori oral infection in smoking patients with chronic generalized periodontitis on the background of chronic hyperacidal gastritis during treatment

2020 ◽  
Vol 40 (4) ◽  
pp. 50-54
Author(s):  
O. L. Zolotukhina ◽  
◽  
Ju. G. Romanova ◽  
O. V. Maslov ◽  
◽  
...  
Keyword(s):  
Risk Factors ◽  
Helicobacter Pylori ◽  
Oral Cavity ◽  
Urease Activity ◽  
Rapid Test ◽  
Oral Infection ◽  
Helicobacter Pylori Infection ◽  
Natural Origin ◽  
Periodontal Tissues

Diseases of periodontal tissues occupy one of the leading positions among modern dental problems, namely the multifactorial nature of these diseases. In modern dental science, the issue of the development of periodontal pathology against the background of somatic pathology and risk factors remains relevant. Pathology of periodontal tissues in 68–90 % of cases is accompanied by chronic diseases of the gastrointestinal tract. Today, there is no doubt that Helicobacter pylori infection can be present in the biotopes of the oral cavity and can affect the course of periodontal pathology. As you know, smoking is one of the important risk factors for the development of inflammatory-dystrophic diseases of periodontal tissues, which can aggravate the course of the latter. The purpose of the work is to determine the prevalence of oral Helicobacter pylori infection in tobacco-dependent patients with chronic generalized periodontitis on the background of chronic hyperacid gastritis during treatment. Patients who received the proposed therapeutic and prophylactic complex (ultraphonophoresis procedures with the created gel «Apisan», and probiotic drug BioGaia ProDentis and angioprotective drug of natural origin — Detralex) showed a gradual decrease in the level of total urease activity and, as a consequence, a decrease the prevalence of Helicobacter pylori infection in the oral cavity according to the results of a urease rapid test with material from the oral cavity, both in the presence of a risk factor — smoking, and in its absence. The use of the proposed therapeutic and prophylactic complex proved to be effective in reducing the prevalence of oral Helicobacter pylori infection in smoking patients and patients who do not smoke, with chronic generalized periodontitis against the background of chronic hyperacidal gastritis associated with Helicobacter pylori.

Eco-friendly spectrophotometric methods for assessment of alfuzosin and solifenacin in their new pharmaceutical formulation; Green profile evaluation via eco-scale and GAPI tools

2020 ◽  
Vol 16 ◽  
Author(s):  
Mamdouh R. Rezk ◽  
Mina Wadie ◽  
Soheir A. Weshahy ◽  
Mahmoud A. Tantawy
Keyword(s):  
Minor Component ◽  
Time Saving ◽  
Prostate Hyperplasia ◽  
Spectrophotometric Methods ◽  
Ratio Difference ◽  
Ich Guidelines ◽  
Mean Centering ◽  
Benign Prostate ◽  
Urological Diseases

Background: Alfuzosin is recently co-formulated with solifenacin for relieving two coincident urological diseases, namely; benign prostate hyperplasia and overactive bladder Objective: Herein, green, simple and rapid spectrophotometric methods were firstly developed for simultaneous determination of the two cited drugs in their co-formulated pharmaceutical capsule Methods: Alfuzosin, which is the major component in the dosage form, was directly assayed at its extended wavelength at 330.0 nm. The challenging spectrum of the minor component, solifenacin, was resolved by five spectrophotometric methods, namely; dual wavelength (DW) at 210.0 & 230.0 nm, first derivative (1D) at 222.0 nm, ratio difference (RD) at 217.0 - 271.0 nm , derivative ratio (1DD) at 223.0 and mean centering of ratio spectra (MC) at 217.0 nm Results: The Proposed methods were successfully validated as per ICH guidelines. Alfuzosin showed linearity over the range of 4.0 - 70.0 μg/mL, while that of solifenacin were 4.0 - 50.0 μg/mL for DW, 2.0 - 70.0 μg/mL for 1D and RD methods, 1.0 - 70.0 μg/mL for 1DD and 4.0 - 70.0 μg/mL for MC method. Statistical comparison with their official ones showed no noticeable differences. The methods showed good applicability for assaying drugs in their newly combination. Besides eco-scale, the greenness profile of the methods was assessed and compared with the reported spectrophotometric one via the newest metric tool; green analytical procedure index (GAPI). Conclusions: The proposed methods are superior in not only being smart, accurate, selective, robust and time-saving, but also in using distilled water as an eco-friendly and cheap solvent

Sign in / Sign up

Export Citation Format

Share Document