Optimization of Extraction Parameters of Reverse Iontophoretic Determination of Blood Glucose in an Artificial Skin Model

Background: Reverse İontophoresis (RI) is one of the promising non-invasive technologies. It relies on the transition of low magnitude current through the skin and thus glucose measurement becomes possible as it is extracted from the surface during this porter current flow. Objective: This paper deals with the development and optimization of an RI determination method for glucose. CE dialysis membrane based artificial skin model was developed and the dependence of RI extraction on various experimental parameters was investigated. Method: Dependence of RI extraction performance on noble electrodes (platinum, silver, palladium, ruthenium, rhodium) was checked with CA, CV and DPV, in a wide pH and ionic strength range. Optimizations on inter-electrode distance, potential type and magnitude, extraction time, gel type, membrane MWCO, usage frequency, pretreatment, artificial body fluids were performed. Results: According to the optimized results, the inter-electrode distance was 7.0 mm and silver was the optimum noble metal. Optimum pH and ionic strength were achieved with 0.05M PBS at pH 7.4. Higher glucose yields were obtained with DPV, while CA and CV achieved almost the same levels. During CA, +0.5V achieved the highest glucose yield and higher potential even caused a decrease. Glucose levels could be monitored for 24 hours. CMC gel was the optimum collection media. Pretreated CE membrane with 12kD MWCO was the artificial skin model. Pretreatment affected the yields while its condition caused no significant difference. Except PBS solution (simulated as artificial plasma), among the various artificial simulated body fluids, intestinal juice formulation (AI) and urine formulation U2 were the optimum extraction media, respectively. Conclusion: In this study, various experimental parameters (pretereatment procedure, type and MWCO values of membranes, inter-electrode distance, electrode material, extraction medium solvents, ionic strength and pH, collection medium gel type, extraction potential type and magnitude, extraction time and etc) were optimized for the non-invasive RI determination of glucose in a CE dialysis membrane-based artificial skin model and various simulated artificial body fluids.

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The interaction of morin and morin-5’-sulfonic acid with lead(II): Study of the 1:1 complex formation process in aqueous solution

Main Group Metal Chemistry ◽

10.1515/mgmc-2019-0007 ◽

2019 ◽

Vol 42 (1) ◽

pp. 67-72

Author(s):

Maxim A. Lutoshkin ◽

Boris N. Kuznetsov ◽

Vladimir A. Levdanskiy

Keyword(s):

Aqueous Solution ◽

Ionic Strength ◽

Sulfonic Acid ◽

Computational Models ◽

Experimental Parameters ◽

Wide Ph Range ◽

Ph Range ◽

Aqueous Complexation ◽

Complex Formation Process

Abstract This article focuses on the aqueous complexation between two flavonoids (morin and morinsulfonate) and Pb2+ at constant ionic strength I=0.5 M (NaClO4). The determination of stability constants of ML complexes were performed at wide pH range. Two obtained constants are 14.8 ± 0.1 and 15.2 ± 0.1 logarithmic units for morin and morin-5’-sulfonic acid, respectively. For estimating the thermodynamic stability of the complexes studied, the Def2-SV(P)/DFT/PBE0/SMD method has been used. Different computational models were tested to describe the data obtained. The theoretical values of logK reproduce the experimental parameters within reasonable errors.

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Determination of four trace preservatives in street food by ionic liquid-based dispersive liquid-liquid micro-extraction

Chemical Papers ◽

10.2478/s11696-011-0071-9 ◽

2011 ◽

Vol 65 (6) ◽

Cited By ~ 10

Author(s):

Peng Yang ◽

Haixia Ren ◽

Hongdeng Qiu ◽

Xia Liu ◽

Shengxiang Jiang

Keyword(s):

Ionic Liquid ◽

Sodium Chloride ◽

Ionic Strength ◽

Extraction Process ◽

Influential Factors ◽

Extraction Time ◽

Experimental Conditions ◽

Street Food ◽

Extraction Solvent

AbstractA rapid and simple ionic liquid-based dispersive liquid-liquid micro-extraction (DLLME) method has been developed to pre-concentrate four paraben preservatives (methylparaben, ethylparaben, propylparaben, and butylparaben) from street food (pancakes). Several potentially influential factors such as the type of ionic liquid and disperser solvent, extraction time, sample pH, ionic strength, and the volume of the ionic liquid and disperser solvent were investigated. The optimum experimental conditions for the proposed micro-extraction process were: 0.1 mL of 1-octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) as an extraction solvent, 0.1 mL of acetonitrile as a disperser solvent, 5 min extraction time, and sample ionic strength of 30 % sodium chloride in water sample at pH 6.0. The LODs and LOQs were in the range of 1.0–1.5 ng g−1 and 3.5–4.5 ng g−1, respectively. Spiking recoveries were in the range of 60.1–79.5 % and the associated RSDs were all in the range of 1.8–7.0 %. The results show that DLLME is a suitable method for the determination of parabens in pancake samples and ionic liquid is a good extractant in this process.

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A new method for non-invasive, manoeuvre-free determination of “static” pressure–volume curves during dynamic/therapeutic mechanical ventilation

Acta Anaesthesiologica Scandinavica ◽

10.1034/j.1399-6576.2000.00516.x ◽

2000 ◽

Vol 44 (5) ◽

pp. 578 ◽

Cited By ~ 4

Author(s):

S. Kárason

Keyword(s):

Mechanical Ventilation ◽

Static Pressure ◽

New Method ◽

Non Invasive

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SERUM TRIIODOTHYRONINE DETERMINATION BY SATURATION ANALYSIS

Acta Endocrinologica ◽

10.1530/acta.0.0720714 ◽

1973 ◽

Vol 72 (4) ◽

pp. 714-726 ◽

Cited By ~ 3

Author(s):

A. Burger ◽

B. Miller ◽

C. Sakoloff ◽

M. B. Vallotton

Keyword(s):

Ionic Strength ◽

Limit Of Detection ◽

Improved Method ◽

Accuracy Of Measurement ◽

Tracer Amount ◽

The Mean ◽

Physiological Values ◽

Hyperthyroid Patients ◽

Solvent Blank

ABSTRACT An improved method for the determination of serum triiodothyronine (T3) has been developed. After addition of a tracer amount of the hormone, T3 was extracted from 1 ml serum under conditions of pH and ionic strength which favoured T3 extraction (89%) over thyroxine (T4) extraction (58%). Chromatography of the extracted material on Sephadex LH-20 separated T3 completely from residual T4. The T3 eluate was dried, then re-dissolved in 0.5 ml NaOH 0.04 n. To 0.2 ml duplicate aliquots, a standard amount of TBG was added for the competitive protein analysis. After one hour incubation at 4°C, separation of bound from free T3 was achieved on small Sephadex G-25 columns. Overall recovery was 67 ± 10.8% and correction for the loss was made. The solvent blank was 37 ± 27 (sd) ng/100 ml. Accuracy of measurement of known quantities of T3 added to serum was 98.4%. The coefficient of variation within the assay was 6.2% and between the assays it was 11.4%. The limit of detection (0.1 ng) corresponded to a concentration of 25 ng/100 ml. T4 added to serum did not interfere with T3 determination until high non-physiological values were reached. The mean ± sd serum T3 in 54 euthyroid subjects was 153 ± 58 ng/100 ml and in 24 hyperthyroid patients it was 428 ±186 ng/100 ml; 4 out of the 24 hyperthyroid values were within 2 sd of the mean euthyroid group. All the values found in the euthyroid group were well above the limit of detection of the method.

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Bioimpedance Spectroscopy as a Non-invasive Method of Determination of the Hydration Status in Hemodialysis Patients

Acta Mechanica Slovaca ◽

10.2478/v10147-011-0023-y ◽

2010 ◽

Vol 14 (2) ◽

pp. 72-77

Author(s):

J. Rosina ◽

Jana Vranova ◽

Ondrej Remes ◽

Katarina Nehezova ◽

I. Rychlik

Keyword(s):

Hemodialysis Patients ◽

Hydration Status ◽

Bioimpedance Spectroscopy ◽

Non Invasive ◽

Method Of Determination ◽

Invasive Method

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INFLUENCE OF OFFICE BLEACHING SYSTEMS ON THE RESISTANCE OF HARD TOOTH TISSUES

"Medical & pharmaceutical journal "Pulse" ◽

10.26787/nydha-2686-6838-2020-22-12-119-125 ◽

2020 ◽

pp. 119-125

Author(s):

Magsumova O.A. ◽

Postnikov M.A. ◽

Ryskina E.A. ◽

Tkach T.M. ◽

Polkanova V.A.

Keyword(s):

Informed Consent ◽

Oral Fluid ◽

Personal Data ◽

Acid Resistance ◽

Non Invasive ◽

Hard Tissues ◽

Voluntary Informed Consent

One of the non-invasive methods for treating discoloration of hard tooth tissues is teeth whitening. The aim of this work is to assess the dynamics of changes in the acid resistance of enamel and hard tissues of teeth and the rate of its remineralization after the procedure of office teeth whitening. The study involved 123 patients aged 18 to 35 years with discoloration of various origins, with the color of hard tooth tissues on the Vita Classic A2 scale and darker. Before performing the office, teeth whitening procedure, all patients gave their written voluntary informed consent to participate in this study, as well as consent to the processing of personal data. Depending on the chosen method of office teeth whitening, patients were divided into 3 groups. The resistance of hard tooth tissues was judged based on the determination of TOER and CASRE tests. These indicators were determined at various times (5 days before the office teeth whitening procedure, 5 days after it, after 14, 30 days and 6 months). Regardless of the chosen whitening system, the office teeth whitening procedure is accompanied by a decrease in the enamel's resistance to acids and a decrease in the rate of its remineralization. The remineralizing function of oral fluid promotes the positive dynamics of the studied parameters after 14 days and after 30 days values increased due to the appointment of remineralizing therapy to all patients in 2 weeks after the teeth whitening procedure. After 6 months, all patients had high enamel resistance and the rate of its remineralization.

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Clothing for protection against contact with blood and body fluids. Determination of the resistance of protective clothing materials to penetration by blood and body fluids. Test method using synthetic blood

10.3403/03107767 ◽

2004 ◽

Keyword(s):

Protective Clothing ◽

Body Fluids ◽

Test Method

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Biomarkers of Alcohol Consumption in Body Fluids - Possibilities and Limitations of Application in Toxicological Analysis

Current Medicinal Chemistry ◽

10.2174/0929867324666171005111911 ◽

2019 ◽

Vol 26 (1) ◽

pp. 177-196 ◽

Cited By ~ 5

Author(s):

Mateusz Kacper Woźniak ◽

Marek Wiergowski ◽

Jacek Namieśnik ◽

Marek Biziuk

Keyword(s):

Alcohol Consumption ◽

Forensic Toxicology ◽

Body Fluids ◽

Ethyl Esters ◽

Ethyl Glucuronide ◽

Human Organism ◽

Analytical Toxicology ◽

Preparation Methods ◽

Toxicological Analysis

Background:Ethyl alcohol is the most popular legal drug, but its excessive consumption causes social problems. Despite many public campaigns against alcohol use, car accidents, instances of aggressive behaviour, sexual assaults and deterioration in labor productivity caused by inebriated people is still commonplace. Fast and easy diagnosis of alcohol consumption is required in order to introduce proper and effective therapy, and is crucial in forensic toxicology analysis. The easiest method to prove alcohol intake is determination of ethanol in body fluids or in breath. However, since ethanol is rapidly metabolized in the human organism, only recent consumption can be detected using this method. Because of that, the determination of alcohol biomarkers was introduced for monitoring alcohol consumption over a wider range of time.Objective:The objective of this study was to review published studies focusing on the sample preparation methods and chromatographic or biochemical techniques for the determination of alcohol biomarkers in whole blood, plasma, serum and urine.Methods:An electronic literature search was performed to discuss possibilities and limitations of application of alcohol biomarkers in toxicological analysis.Results:Authors described the markers of alcohol consumption such as: ethanol, its nonoxidative metabolites (ethyl glucuronide, ethyl sulfate, phosphatidylethanol, ethyl phosphate, fatty acid ethyl esters) and oxidative metabolites (acetaldehyde and acetaldehyde adducts). We also discussed issues concerning the detection window of these biomarkers, and possibilities and limitations of their use in routine analytical toxicology for monitoring alcohol consumption or sobriety during alcohol therapy.

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Titration of sulphates and lead using lead ion selective electrode

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19810368 ◽

1981 ◽

Vol 46 (2) ◽

pp. 368-376 ◽

Cited By ~ 4

Author(s):

Josef Veselý

Keyword(s):

Ionic Strength ◽

Electrode Surface ◽

Salt Content ◽

Ion Selective Electrode ◽

Lead Ion ◽

Selective Electrode ◽

Limit Of Determination ◽

Total Salt Content ◽

Automatic Titration

Titration of sulphates with lead perchlorate employing lead ion selective electrode indication was studied using additions of various organic solvents at different pH' and ionic strength values. As the optimum emerged systems with 60-70% 1,4-dioxane, pH' 5.3-5.6. After dehydration with sodium hydroxide, dioxane must be freed from the electrode surface-oxidizing impurities by their reduction with sodium metal and subsequent distillation. The method was applied to determination of sulphates in mountain spring waters. Units of ppm can be determined; the limit of determination, however, depends considerably on the content of dioxane, total salt content in the sample, and speed of the semi-automatic titration. Lead can be determined with EDTA in concentrations down to c(Pb2+) = 5 . 10-6 mol l-1.

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