scholarly journals Sensing Cd(II) Using a Disposable Optical Sensor Based on a Schiff Base Immobilisation on a Polymer-Inclusion Membrane. Applications in Water and Art Paint Samples

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4414
Author(s):  
Lorena Sánchez-Ponce ◽  
María Dolores Galindo-Riaño ◽  
María José Casanueva-Marenco ◽  
María Dolores Granado-Castro ◽  
Margarita Díaz-de-Alba
Keyword(s):  
Schiff Base ◽  
Optical Sensor ◽  
Limit Of Detection ◽  
Fractional Factorial ◽  
Buffer Solution ◽  
Experimental Conditions ◽  
Inclusion Membrane ◽  
Polymer Inclusion Membrane ◽  
Relative Standard ◽  
Base Polymer

A disposable colour-changeable optical sensor based on an interesting polymer inclusion-membrane (PIM) was designed to determine Cd(II) ions in aqueous medium. The Schiff base 2-acetylpyridine benzoylhydrazone (2-APBH) immobilised on the polymer membrane was used as a sensing molecule. The amounts of the PIM components were optimised by a 32 fractional factorial design with two central points and two blocks. The best optical sensor composition consisted of 2.5 g of poly(vinylchloride) (PVC) as a base polymer, 3 mL of tributyl phosphate (TBP) as a plasticiser, and 0.02 g of 2-APBH as a reagent. The sensor showed a good linear response in the range from 0.02 mg L−1 (limit of detection) to 1 mg L−1 of Cd(II) under the following experimental conditions: pH 9.5 (adjusted using ammonium chloride buffer solution at 0.337 mol L−1), 60 min of exposure time plus 2 min of sonication (pulses at 2 s intervals), and 10 min of short-term stability. The relative standard deviation of the method was determined to be 4.04% for 0.4 mg L−1 of Cd(II). The optical sensor was successfully applied to the determination of Cd(II) in natural-water and art-paint samples.

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.

scholarly journals Simultaneous Voltammetric Detection of Acetaminophen and Caffeine Base on Cassava Starch—Fe3O4 Nanoparticles Modified Glassy Carbon Electrode

Chemosensors ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 49 ◽  
Author(s):  
Ani Mulyasuryani ◽  
Rachmat Tjahjanto ◽  
Robi’atul Andawiyah
Keyword(s):  
Fe3o4 Nanoparticles ◽  
Limit Of Detection ◽  
Sodium Tripolyphosphate ◽  
Crosslinking Agent ◽  
Differential Pulse ◽  
Cassava Starch ◽  
Buffer Solution ◽  
Mixture Ratio ◽  
Relative Standard ◽  
Voltammetric Detection

The new molecularly imprinted polymer (MIP) membrane based on cassava starch—Fe3O4—was developed to detect acetaminophen and caffeine simultaneously with the differential pulse voltammetry (DPV) method. Cassava starch was reacted with sodium tripolyphosphate (STPP) as a crosslinking agent, while acetaminophen and caffeine were added as templates. The Fe3O4 nanoparticles in the composite were added to increase the sensor’s sensitivity. The experimental results show that the ratio between cassava starch:STPP:acetaminophen/caffeine in the mixture for MIP membranes influences the sensitivity of the sensor obtained. MIP membranes with the best sensitivity is produced at a mixture ratio of 2:2:1. The sensor performance is also affected by the pH of the solution and the type of buffer solution used. The sensor works very well at pH 2 in PB solution. Sensors produced from GCE modified with MIP membrane from cassava starch—Fe3O4 with acetaminophen and caffeine as templates have linear range concentrations, respectively, at 50–2000 µM and 50–900 µM. Sensor sensitivity was 0.5306 A/M against acetaminophen and 0.4314 A/M against caffeine with Limit of Detection (LoD), respectively, 16 and 23 µM. Sensor selectivity and sensitivity are better than those without MIP and can be applied for the determination of the content of acetaminophen in headache medicine, with an accuracy of 96–99% and with Relative Standard Deviation (RSD) 0.9–2.56%.

scholarly journals A Stability Indicating Assay Method Development and Validation for the Frovatriptan Succinate Monohydrate by Using UV: A Spectrophotometric Technique

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Hitesh Verma ◽  
Surajpal Verma ◽  
Harmanpreet Singh
Keyword(s):  
Method Development ◽  
Limit Of Detection ◽  
Assay Method ◽  
Forced Degradation ◽  
Solution Stability ◽  
Limit Of Quantification ◽  
Experimental Conditions ◽  
Stability Indicating ◽  
Ich Guidelines ◽  
Relative Standard

A new simple, reliable, inexpensive, and accurate method was developed for the quantification of Frovatriptan Succinate Monohydrate in different physiological media at 244 nm in bulk and in tablet dosage forms. The developed method is an attempt to surpass the disadvantages associated with the reported methods, namely, less sensitive and tedious in usage for routine purposes. Beer’s law was followed over the range of 1.0 µg/mL to 4.5 µg/mL. Stability indicating assay method was developed and validated as per the ICH guidelines using various parameters, for example, accuracy, precision, limit of quantification, limit of detection, robustness, ruggedness, solution stability, recovery, forced degradation (hydrolysis, photo degradation, thermal degradation, and oxidation), and so forth. Percent relative standard deviation associated with all the parameters was less than 2, showing compliance with the acceptance criteria of ICH guidelines. The developed method was very sensitive as limit of quantification and limit of detection were found to be 0.025 µg/mL and 0.00625 µg/mL, respectively. Forced degradation studies of drug reveal good stability under the chosen experimental conditions.

Online Determination of Anionic Surfactant in Environmental Water

2012 ◽  
Vol 610-613 ◽  
pp. 1113-1116
Author(s):  
Liang Wei ◽  
Yi Chun Dai
Keyword(s):  
Anionic Surfactant ◽  
Sodium Dodecyl ◽  
Environmental Water ◽  
Buffer Solution ◽  
Experimental Conditions ◽  
Ethyl Violet ◽  
Relative Standard ◽  
Potassium Hydrogen ◽  
Standard Solution

It was found that ethyl violet can react with sodium dodecyl benzene sulfate (SDBS) to form ion associates in pH 2.2 ~ 2.8 of buffer solution of potassium hydrogen phthalate and hydrochloric acid in the presence of polyvinyl alcohol. Based on this, a method was proposed for online determination of anionic surfactant in environmental waterby. Under the optimum experimental conditions, Beers law was obeyed in the concentration range of 80 µg/L ~ 3500 µg/L of anionic surfactant (SDBS). The relative standard deviation of 2.1% was was obtained by injecting 800 µg/L of sodium dodecyl benzene sulfate standard solution (n=10). The detection limit calculated from three times of the average background noise was 4.39 µg/L. The proposed method had been applied successfully to the determination of anionic surfactant in environmental water and the results showed good agreement with that of the standard method.

scholarly journals Use of Dispersive Liquid-Liquid Microextraction and UV-Vis Spectrophotometry for the Determination of Cadmium in Water Samples

2014 ◽  
Vol 2014 ◽  
pp. 1-4 ◽  
Author(s):  
J. Pérez-Outeiral ◽  
E. Millán ◽  
R. Garcia-Arrona
Keyword(s):  
Water Samples ◽  
Limit Of Detection ◽  
Experimental Conditions ◽  
Cadmium Determination ◽  
A Value ◽  
Relative Standard ◽  
Potential Applicability ◽  
Dispersive Liquid Liquid Microextraction ◽  
Liquid Microextraction

A simple and inexpensive method for cadmium determination in water using dispersive liquid-liquid microextraction and ultraviolet-visible spectrophotometry was developed. In order to obtain the best experimental conditions, experimental design was applied. Calibration was made in the range of 10–100 μg/L, obtaining good linearity (R2 = 0.9947). The obtained limit of detection based on calibration curve was 8.5 μg/L. Intra- and interday repeatability were checked at two levels, obtaining relative standard deviation values from 9.0 to 13.3%. The enrichment factor had a value of 73. Metal interferences were also checked and tolerable limits were evaluated. Finally, the method was applied to cadmium determination in real spiked water samples. Therefore, the method showed potential applicability for cadmium determination in highly contaminated liquid samples.

scholarly journals Sensitive Determination of Terazosin in Pharmaceutical Formulations and Biological Samples by Ionic-Liquid Microextraction Prior to Spectrofluorimetry

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Mohsen Zeeb ◽  
Mahdi Sadeghi
Keyword(s):  
Ionic Liquid ◽  
Ionic Strength ◽  
Biological Samples ◽  
Limit Of Detection ◽  
Pharmaceutical Formulations ◽  
Experimental Conditions ◽  
Relative Standard ◽  
Common Ion ◽  
Liquid Microextraction

An efficient and environmentally friendly sample preparation method based on the application of hydrophobic 1-Hexylpyridinium hexafluorophosphate [Hpy][PF6] ionic liquid (IL) as a microextraction solvent was proposed to preconcentrate terazosin. The performance of the microextraction method was improved by introducing a common ion of pyridinium IL into the sample solution. Due to the presence of the common ion, the solubility of IL significantly decreased. As a result, the phase separation successfully occurred even at high ionic strength, and the volume of the settled IL-phase was not influenced by variations in the ionic strength (up to 30% w/v). After preconcentration step, the enriched phase was introduced to the spectrofluorimeter for the determination of terazosin. The obtained results revealed that this system did not suffer from the limitations of that in conventional ionic-liquid microextraction. Under optimum experimental conditions, the proposed method provided a limit of detection (LOD) of 0.027 μg L−1and a relative standard deviation (R.S.D.) of 2.4%. The present method was successfully applied to terazosin determination in actual pharmaceutical formulations and biological samples. Considering the large variety of ionic liquids, the proposed microextraction method earns many merits, and will present a wide application in the future.

scholarly journals Magnetic Ion Imprinted Polymers (MIIPs) for Selective Extraction and Preconcentration of Sb(III) from Environmental Matrices

Polymers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 21
Author(s):  
Silindokuhle Jakavula ◽  
Nkositetile Raphael Biata ◽  
Kgogobi M. Dimpe ◽  
Vusumzi Emmanuel Pakade ◽  
Philiswa Nosizo Nomngongo
Keyword(s):  
Environmental Samples ◽  
Limit Of Detection ◽  
Selective Extraction ◽  
Fractional Factorial ◽  
Emission Spectrometry ◽  
Icp Oes ◽  
Aquatic Life ◽  
Relative Standard ◽  
Ion Imprinted ◽  
Ion Imprinted Polymers

Antimony(III) is a rare element whose chemical and toxicological properties bear a resemblance to those of arsenic. As a result, the presence of Sb(III) in water might have adverse effects on human health and aquatic life. However, Sb(III) exists at very ultra-trace levels which may be difficult for direct quantification. Therefore, there is a need to develop efficient and reliable selective extraction and preconcentration of Sb(III) in water systems. Herein, a selective extraction and preconcentration of trace Sb(III) from environmental samples was achieved using ultrasound assisted magnetic solid-phase extraction (UA-MSPE) based on magnetic Sb(III) ion imprinted polymer-Fe3O4@SiO2@CNFs nanocomposite as an adsorbent. The amount of antimony in samples was determined using inductively coupled plasma optical emission spectrometry (ICP-OES). The UA-MSPE conditions were investigated using fractional factorial design and response surface methodology based on central composite design. The Sb(III)-IIP sorbent displayed excellent selectivity towards Sb(III) as compared to NIIP adsorbent. Under optimised conditions, the enrichment factor, limit of detection (LOD) and limit of quantification (LOQ) of UA-MSPE/ICP-OES for Sb(III) were 71.3, 0.13 µg L−1 and 0.44 µg L−1, respectively. The intra-day and inter-day precision expressed as relative standard deviations (%RSDs, n = 10 and n = 5) were 2.4 and 4.7, respectively. The proposed analytical method was applied in the determination of trace Sb(III) in environmental samples. Furthermore, the accuracy of the method was evaluated using spiked recovery experiments and the percentage recoveries ranged from 95–98.3%.

scholarly journals Fast Determination of Auramine O in Food by Adsorptive Stripping Voltammetry

2019 ◽  
Vol 2019 ◽  
pp. 1-6 ◽  
Author(s):  
Thuong Nguyen Thi Kim ◽  
Thi Thu Bui ◽  
Anh Tuan Pham ◽  
Van Thang Duong ◽  
Thi Huong Giang Le
Keyword(s):  
Limit Of Detection ◽  
Electrochemical Behaviour ◽  
Pulse Amplitude ◽  
Reduction Peak ◽  
Hanging Mercury Drop Electrode ◽  
Experimental Conditions ◽  
Mercury Drop Electrode ◽  
Relative Standard ◽  
Limit Of Quantitation ◽  
Auramine O

The electrochemical behaviour of auramine O on the hanging mercury drop electrode has been investigated by cyclic and square wave voltammetry method. Reduction peak of auramine O was irreversible and adsorptive on the hanging mercury drop electrode. The optimal conditions were chosen to be Briton–Robinson buffer pH 9.0, accumulation potential −0.5 V vs. Ag/AgCl/KCl, accumulation time 60 s, pulse amplitude 250 mV·s−1, and frequency 50 Hz. At the optimum experimental conditions, the peak of the target analyte was sharp and asymmetric. The linearity of the peak current depending on the concentration ranged from 4.0 × 10−8 to 6.4 × 10−7 mol L−1. The limit of detection and limit of quantitation were 2.46 × 10−8 mol L−1 and 8.21 × 10−8 mol L−1, respectively. The recovery and relative standard deviation were 94.9% and 2.0% (n = 5). The developed method was successfully applied to determine auramine O in chicken samples with an appropriate sample preparation.

scholarly journals Spectrophotometric and RP-HPLC Methods for Determining Cefotaxime Sodium in Pharmaceutical Preparations

2020 ◽  
Vol 32 (6) ◽  
pp. 1314-1320
Author(s):  
Lamya A. Sarsam ◽  
Salim A. Mohammed ◽  
Sahar A. Fathe
Keyword(s):  
Limit Of Detection ◽  
Phosphate Buffer Solution ◽  
Pharmaceutical Preparations ◽  
Molar Absorptivity ◽  
Hplc Method ◽  
Buffer Solution ◽  
Limit Of Quantification ◽  
Rp Hplc ◽  
Relative Standard

A rapid, simple and sensitive spectrophotometric and RP-HPLC methods have been developed for the quantitative determination of cefotaxime-Na in both pure and dosage forms. The spectrophotometric method was based on diazotization of cefotaxime-Na and then coupling with 8-hydroxyquinoline in an alkaline medium. The resulting azo dye exhibited maximum absorption at 551 nm with a molar absorptivity of 0.597 × 104 L mol-1 cm-1. Beer′s law was obeyed over the range 10-700 μg/25 mL (i.e. 0.4-28.0 ppm) with an excellent determination coefficient (R2 = 0.9993). The limit of detection (LOD) and limit of quantification (LOQ) were found to be 0.0194 and 0.3765 μg mL-1, respectively. The recoveries were obtained in the range 97.3-102.5% and the relative standard deviation (RSD) was better than ± 1.56. The HPLC method has been developed for the determination of cefotaxime-Na. The analysis were carried out on a C18 column and a mobile phase composed of acetonitrile and phosphate buffer solution (0.024M KH2PO4 and 0.01M H3PO4) at pH 3.5 in the ratio of 60:40 (v:v), with a flow rate of 1.0 mL min-1 and UV detection at 258 nm. The proposed method showed good linearity (in a range of concentration 1.0-200 μg mL-1. The recovery percent and a relative standard deviations were found in the range 96 to 104.8% and ± 0.017 to ± 0.031%, respectively. Both methods were applied successfully to the assay of cefotaxime-Na in commercial injection preparations.

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