scholarly journals Inhibitive Determination of Hg(II) in Aqueous Solution Using Urease Amperometric Biosensor

2019 ◽  
Vol 19 (3) ◽  
pp. 786 ◽  
Author(s):  
Dhony Hermanto ◽  
Bambang Kuswandi ◽  
Dwi Siswanta ◽  
Mudasir Mudasir
Keyword(s):  
Dynamic Range ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Amperometric Biosensor ◽  
Reduction Peak ◽  
Polyelectrolyte Complexes ◽  
Indirect Determination ◽  
Biosensor Response ◽  
Good Agreement

An amperometric biosensor for the indirect determination of Hg(II) has been developed based on inhibition of urease (EC 3.5.1.5) immobilized into alginate–chitosan polyelectrolyte complexes membrane. The biosensor response was monitored by following the reduction peak of hydrolyzed urea at around -0.15 V. The amperometric biosensor has a dynamic range 40–90 ppb Hg(II) with limit of detection of 66.45 ppb toward Hg(II) ions, repeatability (CV) value of 0.86% and only Ag(I) as the main potential interference. The sensor shows a stable and reproducible response for more than 2 weeks when it stored dry at 4 °C. The analytical results of Hg(II)-spiked water sample showed a good agreement with those obtained by atomic absorption spectrometry method, suggesting that the developed method may be applied in the determination of Hg(II) in the water samples.

Indirect Determination of Amikacin by Gold Nanoparticles as Redox Probe

2020 ◽  
Vol 17 ◽  
Author(s):  
Mansureh Alizadeh ◽  
Mandana Amiri ◽  
Abolfazl Bezaatpour
Keyword(s):  
Gold Nanoparticles ◽  
Bacterial Infections ◽  
Limit Of Detection ◽  
Pharmaceutical Preparation ◽  
Cathodic Peak ◽  
Easy Method ◽  
Peak Current ◽  
Indirect Determination ◽  
Tract Infections

: Amikacin is an aminoglycoside antibiotic used for many gram-negative bacterial infections like infections in the urinary tract, infections in brain, lungs and abdomen. Electrochemical determination of amikacin is a challenge in electroanalysis because it shows no voltammetric peak at the surface of bare electrodes. In this approach, a very simple and easy method for indirect voltammetric determination of amikacin presented in real samples. Gold nanoparticles were electrodeposited at the surface of glassy carbon electrode in constant potential. The effect of several parameters such as time and potential of deposition, pH and scan rates on signal were studied. The cathodic peak current of Au3+ decreased with increasing amikacin concentration. Quantitative analysis of amikacin was performed using differential pulse voltammetry by following cathodic peak current of gold ions. Two dynamic linear ranges of 1.0 × 10−8–1.0 × 10-7 M and 5.0 × 10−7–1.0 × 10-3 M were obtained and limit of detection was estimated 3.0× 10−9 M. The method was successfully determined amikacin in pharmaceutical preparation and human serum. The effect of several interference in determination of amikacin was also studied.

Determination of Some Nitrophenols by Atomic Absorption Spectrometry (AAS) After Extraction of Ionic Associates Involving the Bipyridylocopper(II) or Phenanthrolinocopper(II) Complex

1994 ◽  
Vol 59 (10) ◽  
pp. 2227-2234 ◽  
Author(s):  
Václav Stužka ◽  
Jaromír Souček
Keyword(s):  
Molecular Weight ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Methyl Isobutyl Ketone ◽  
Absorption Spectrometry ◽  
Methyl Isobutyl ◽  
Isobutyl Ketone ◽  
Indirect Determination ◽  
Ionic Associates

A new method has been developed for the indirect determination of nitroso- and nitrophenols by atomic absorption spectrometry (AAS) after extraction of ionic associates involving bipyridylocopper(II) (CuDP) or phenanthrolinocopper(II) (CuPH) complexes. Nitrobenzene and methyl isobutyl ketone appeared to be suitable for the extraction. It was possible to determine several tenths to hundredths of a milligram of nitrophenol in a litre. Extractable associates with CuDP and CuPH are formed by phenols possessing two substituents or by higher molecular weight phenols such as naphthol or hydroxyquinoline. Monosubstituted phenols fail to form associates of this kind.

scholarly journals An Improved Methodology for Determination of Fluorine in Biological Samples Using High-Resolution Molecular Absorption Spectrometry via Gallium Fluorine Formation in a Graphite Furnace

2021 ◽  
Vol 11 (12) ◽  
pp. 5493
Author(s):  
Andrzej Gawor ◽  
Andrii Tupys ◽  
Anna Ruszczyńska ◽  
Ewa Bulska
Keyword(s):  
High Resolution ◽  
Limit Of Detection ◽  
Graphite Furnace ◽  
Absorption Spectrometry ◽  
Biological Tissues ◽  
Biologically Active ◽  
Molecular Absorption ◽  
Biological Origin ◽  
Molecular Absorption Spectrometry

Nowadays growing attention is paid to the control of fluorine content in samples of biological origin as it is present in the form of various biologically active organic compounds. Due to the chemically-rich matrix of biological tissues, the determination of fluorine becomes a very difficult task. Furthermore, a required complex sample preparation procedure makes the determination of the low contents of F by ion chromatography UV-Vis or ion-selective electrodes not possible. High-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS GF MAS) seems to be the best option for this purpose due to its high robustness to matrix interferences, especially in the presence of carefully selected modifiers. In this work the possibility of quantitative F determination in water and animal tissues was examined by measuring the molecular absorption of gallium monofluoride (GaF) at 211.248 nm with the use of a commercially available HR-CS GF MAS system. Experimental conditions for the sensitive and precise determination of fluorine were optimized, including the time/temperature program as well as addition of gallium and modifier mixture in combined mode. Under these conditions the fluoride present in the sample was stabilized up to 600 °C, and the optimum vaporization temperature for GaF was 1540 °C. Palladium and zirconium deposited onto the graphite surface served as solid modifiers; sodium acetate and ruthenium modifiers were added directly to the sample. The limit of detection and the characteristic mass of the method were 0.43 μg/L and 8.7 pg, respectively. The proposed procedure was validated by the use of certified reference materials (CRMs) of lake water and animal tissue; the acceptable recovery was obtained, proving that it can be applied for samples with a similar matrix.

scholarly journals Determination of cobalt in water samples by atomic absorption spectrometry after pre-concentration with a simple ionic liquid-based dispersive liquid-liquid micro-extraction methodology

2010 ◽  
Vol 8 (3) ◽  
pp. 617-625 ◽  
Author(s):  
Hossein Abdolmohammad-Zadeh ◽  
Elnaz Ebrahimzadeh
Keyword(s):  
Ionic Liquid ◽  
Atomic Absorption Spectrometry ◽  
Atomic Absorption ◽  
Water Samples ◽  
Limit Of Detection ◽  
Absorption Spectrometry ◽  
Experimental Conditions ◽  
Flame Atomic Absorption ◽  
Relative Standard

AbstractA rapid dispersive liquid-liquid micro-extraction (DLLME) methodology based on the application of 1-hexylpyridinium hexafluorophosphate [C6py][PF6] ionic liquid (IL) as an extractant solvent was applied for the pre-concentration of trace levels of cobalt prior to determination by flame atomic absorption spectrometry (FAAS). 1-Phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) was employed as a chelator forming a Co-PMBP complex to extract cobalt ions from aqueous solution into the fine droplets of [C6py][PF6]. Some effective factors that influence the micro-extraction efficiency include the pH, the PMBP concentration, the amount of ionic liquid, the ionic strength, the temperature and the centrifugation time which were investigated and optimized. In the optimum experimental conditions, the limit of detection (3s) and the enrichment factor were 0.70 µg L−1 and 60, respectively. The relative standard deviation (RSD) for six replicate determinations of 50 µg L−1 Co was 2.36%. The calibration graph using the pre-concentration system was linear at levels 2–166 µg L−1 with a correlation coefficient of 0.9982. The applicability of the proposed method was evaluated by the determination of trace amounts of cobalt in several water samples.

Determination of Tin in Canned Fruits and Vegetables by Atomic Absorption Spectrometry and Liquid–Liquid Extraction

1994 ◽  
Vol 77 (6) ◽  
pp. 1627-1630 ◽  
Author(s):  
Ana M Martín ◽  
Mercedes Sánchez ◽  
Pedro Espinosa ◽  
Gracia Bagur
Keyword(s):  
Aqueous Phase ◽  
Fruits And Vegetables ◽  
Methyl Ketone ◽  
Absorption Spectrometry ◽  
Liquid Extraction ◽  
Acid Complex ◽  
Liquid Liquid Extraction ◽  
Relative Standard ◽  
Good Agreement

Abstract A method was developed for the determination of tin based on the extraction of its 5,5-methylenedisalicylohydroxamic acid complex with 1.09M isobutyl methyl ketone in tributyl phosphate. After the samples were treated with nitric and hydrochloric acid, the aqueous phase was made to 0.05M in perchloric acid. When the ratio of aqueous phase to organic phase was 4:1 (v/v), the detection limit and the relative standard deviation (n = 7,50 μg tin) were 0.20 μg/mL and 0.9%, respectively. The proposed method was applied to the analysis of tin in canned fruits and vegetables. The results were in good agreement with those obtained by the phenylfluorone method.

scholarly journals The Ionic Associate of Metamizole as an Electrode-Active Component of a PVC Plasticized Membrane Electrode

Chemosensors ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 17
Author(s):  
Sarizhat D. Tataeva ◽  
Kurban E. Magomedov ◽  
Ruslan Z. Zeynalov ◽  
Naida D. Baygishieva ◽  
Viktorya S. Magomedova ◽  
...  
Keyword(s):  
Active Component ◽  
Limit Of Detection ◽  
Membrane Electrode ◽  
Ionic Associate ◽  
Selective Electrode ◽  
Coefficients Of Variation ◽  
Ion Associate ◽  
Phase Functions ◽  
Good Agreement

The technology for manufacturing a film membrane of the metamizole-selective electrode containing ion associate metamizole-octadecylammonium ODAH+MT− as an electrode active component (EAC) has been proposed. The main potentiometric characteristics of the metamizole-selective electrode have been determined. The expediency of the proposed design of the metamizole selective electrode for the determination of metamizole in dosage forms has been substantiated. The best composition of the membrane (wt.%) of the metamizole-selective electrode has corresponded to: ODAH+MT−—5.3; 2-nitrophenyloctylether—63.1; poly(vinyl chloride)—31.6. Electrode-active component in the membrane phase functions as an ion associate ODAH+MT−. Potentiometric characteristics of metamizole-selective electrode have been determined, which corresponded to: linear range 1 × 10−2–1 × 10−4 with limit of detection 4.58 × 10−5 M, electrode function slope −48.5 mV/dec., working interval pH 4.5–7.3, response time 60 s. The potentiometric coefficients of selectivity of the metamizole-selective electrode with respect to various ions have been determined. The possibility of determining metamizole in a medicinal product has been tested. The results of the analyses show good agreement between the two methods (relative error less than 7.0%) with coefficients of variation less than 5% for MT-SE and iodometric methods.

scholarly journals A novel online coupling of ion selective electrode with the flow injection system for the determination of vitamin B1

2016 ◽  
Vol 13 (2) ◽  
pp. 458-469
Author(s):  
Baghdad Science Journal
Keyword(s):  
Flow Injection ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Vitamin B1 ◽  
Pharmaceutical Formulations ◽  
Ion Selective Electrode ◽  
Injection System ◽  
Selective Electrode ◽  
Flow Injection System

A simple, fast, selective of a new flow injection analysis method coupled with potentiometric detection was used to determine vitamin B1 in pharmaceutical formulations via the prepared new selective membranes. Two electrodes were constructed for the determination of vitamin B1 based on the ion-pair vitamin B1-phosphotungestic acid (B1-PTA) in a poly (vinyl chloride) supported with a plasticized di-butyl phthalate (DBPH) and di-butyl phosphate (DBP). Applications of these ion selective electrodes for the determination of vitamin B1 in the pharmaceutical preparations for batch and flow injection systems were described. The ion selective membrane exhibited a near-Nernstian slope values 56.88 and 58.53 mV / decade, with the linear dynamic range of vitamin B1 was 5 x 10-5- 1 x 10-2 and 1 x 10-4-1 x 10-2 mol.L-1, in batch and FIA, respectively. The limit of detection was 3.5 x 10-5 and 9.5 x 10-5 mol.L-1, with the percentage linearity 98.85 and 95.22 in batch and FIA, respectively. The suggested ion selective electrode has been utilized perfection in the determination of vitamin B1 in pharmaceutical formulations using batch and flow injection system, respectively.

scholarly journals SEQUENTIAL MULTI-ELEMENT DETERMINATION OF TRACE-METALS IN BIODIESEL SAMPLES USING HR-CS FAAS

Química Nova ◽  
2020 ◽  
Author(s):  
Alexandre Jesus ◽  
Ariane Zmozinskia ◽  
Diane Laroque ◽  
Márcia Silva
Keyword(s):  
Absorption Spectrometry ◽  
Element Determination ◽  
Continuum Source ◽  
Flame Atomic Absorption ◽  
Student’S T ◽  
Different Sources ◽  
Certified Values ◽  
Good Agreement ◽  
Student’S T Test

In this work the feasibility of sequential multi-element determination of Zn, Fe, Mg, Cu, Na, K, Cr, Al and Ca in biodiesel samples by high-resolution continuum source flame atomic absorption spectrometry (HR-CS FAAS) was investigated. Biodiesel samples obtained from different sources and different chemical processes were analysed. The samples were diluted with n-propanol and water (1.4 mol L-1 HNO3) to form a microemulsion (ME) before its introduction in the HR-CS FAAS using a flow injection mode. The sample B-01 (obtained from soybean oil) was used for optimisation of the instrumental parameters. The accuracy of the proposed method was checked by analysis of certified reference material (CRM) Conostan BDM2A (for K and Na) and BDM2B (for Ca and Mg) and by comparison with acid digestion and recovery tests (for Zn, Fe, Cu, Cr and Al). The obtained results for CRM analysis showed good agreement with certified values within 95% of confidence (Student’s t-test). Recovery tests values ranged from 87-114%. The method developed for the analysis of biodiesel samples is accurate, simple, fast, and suitable for routine application.

scholarly journals Simultaneous Determination of Trace Mefenamic Acid in Pharmaceutical Samples via Flow Injection Fluorometry

2020 ◽  
Vol 10 (03) ◽  
pp. 395-401
Author(s):  
Mohammad K. Hammood ◽  
Maryam Hamed
Keyword(s):  
Flow Injection ◽  
Mefenamic Acid ◽  
Dynamic Range ◽  
Limit Of Detection ◽  
Basic Medium ◽  
Minimum Concentration ◽  
Pharmaceutical Samples ◽  
Fluorescence Measurements ◽  
532 Nm

Mefenamic acid belongs to non-steroidal anti-inflammatory drugs that are used widely for the treatment of analgesia. Our aim from this study is to establish a new assay for the quantitative determination of mefenamic acid (MFA) in the pharmaceutical sample by two sensitive and rapid flow injection-fluorometric methods. A homemade fluorometer was used in fluorescence measurements, which using solid-state laser diode 405 and 532 nm as a source, combined with a continuous flow injection technique. The first method depends on the effect of MFA on calcein blue (CLB) fluorescence at 405 nm. Another method is a study of rhodamine-6G (Rh-6G) fluorescence after adding MFA, and recording at 532 nm. Optimum parameters as fluorescent dye concentration, basic medium, flow rate, sample volume, purge time, and delay coil have been investigated. The dynamic range of MFA was 0.2 to 2 mmol.L-1; 0.5 to 2.3 mmol.L-1 with linearity percentage (% r2) 98.92 and 99.83%, for Rh-6G and CLB, respectively. Limit of detection at a minimum concentration in calibration curve 189.34 and 199.89 ng/sample, for Rh-6G and CLB, respectively. The comparison of developed methods with the classical method (UV-vis spectrophotometry) was achieved. The proposed methods were successfully applied for the determination of MFA in the pharmaceutical samples and can be used as an alternative method.

Sign in / Sign up

Export Citation Format

Share Document