scholarly journals Colorimetric Chemosensor Array for Determination of Halides

Chemosensors ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 39
Author(s):  
Michal Šídlo ◽  
Přemysl Lubal ◽  
Pavel Anzenbacher
Keyword(s):  
Substitution Reaction ◽  
Metal Ion ◽  
Color Change ◽  
Limit Of Detection ◽  
Sensor Arrays ◽  
Paper Strip ◽  
Experimental Conditions ◽  
Halide Anion ◽  
Spectrophotometric Data

The halide anions are essential for supporting life. Therefore, halide anion analyses are of paramount importance. For this reason, we have performed both qualitative and quantitative ana- lyses of halides (chloride, bromide, iodide) using the Tl(III) complex of azodye, 4-(2-pyridylazo)re- sorcinol (PAR), a potential new chemical reagent/sensor that utilizes the substitution reaction whereas the Tl(III)PAR complex reacts with a halide to yield a more stable thallium(III)-halide while releasing the PAR ligand in a process accompanied by color change of the solution. The experimental conditions (e.g., pH, ratio metal ion-to-ligand ratio, etc.) for the substitution reaction between the metal complex and a halide were optimized to achieve increased sensitivity and a lower limit of detection (chloride 7 mM, bromide 0.15 mM, iodide 0.05 mM). It is demonstrated that this single chemosensor can, due to release of colored PAR ligand and the associated analyte-specific changes in the UV/VIS spectra, be employed for a multicomponent analysis of mixtures of anions (chloride + bromide, chloride + iodide, bromide + iodide). The spectrophotometric data evaluated by artificial neural networks (ANNs) enable distinguishing among the halides and to determine halide species concentrations in a mixture. The Tl(III)-PAR complex was also used to construct sensor arrays utilizing a standard 96-well plate format where the output was recorded at several wavelengths (up to 7) using a conventional plate reader. It is shown that the data obtained using a digital scanner employing only three different input channels may also be successfully used for a subsequent ANN analysis. The results of all approaches utilized for data evaluation were similar. To increase the practical utility of the chemosensor, we have developed a test paper strip indicator useful for routine naked-eye visual determination of halides. This test can also be used for halide anion determination in solutions using densitometer. The methodology described in this paper can be used for a simple, inexpensive, and fast routine analysis both in a laboratory as well as in a field setting.

DETERMINATION OF AMINOGLYCOSIDE ANTIBIOTICS BY A COLORIMETRIC METHOD BASED ON THE AGGREGATION OF GOLD NANOPARTICLES

NANO ◽  
2013 ◽  
Vol 08 (04) ◽  
pp. 1350037 ◽  
Author(s):  
RUIYONG WANG ◽  
SHUMIN FAN ◽  
RUIQIANG WANG ◽  
RUI WANG ◽  
HUANJING DOU ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Incubation Time ◽  
Color Change ◽  
Limit Of Detection ◽  
Colorimetric Method ◽  
Aminoglycoside Antibiotics ◽  
Sensing Element ◽  
Experimental Conditions ◽  
Experimental Parameters

A sensitive and selective colorimetric biosensor for determination of gentamicin, amikacin and tobramycin was proposed with the unmodified gold nanoparticles (GNPs) as the sensing element. Gentamicin, amikacin and tobramycin can rapidly induce the aggregation of gold nanoparticles and is accompanied by a color change from red to blue. The concentration of gentamicin, amikacin and tobramycin can be determined by using UV-Vis spectrometer. The experimental parameters were optimized with regard to pH, incubation time and the concentration of the GNPs. Under optimal experimental conditions, the linear range of the colorimetric sensor for gentamicin/amikacin/tobramycin were 2.67–33.93 ng mL-1, 13.33–66.67 ng mL-1 and 20–180 ng mL-1, respectively. The corresponding limit of detection (3σ) was 0.354 ng mL-1, 0.999 ng mL-1 and 0.579 ng mL-1, respectively. This assay was simple and used to detect aminoglycoside antibiotics in milk and medicine products.

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 Cerimetric determination of simvastatin in pharmaceuticals based on redox and complex formation reactions

2018 ◽  
Vol 33 (2) ◽  
pp. 21
Author(s):  
Kanakapura Basavaiah ◽  
Okram Zenita Devi
Keyword(s):  
Limit Of Detection ◽  
Reference Method ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Experimental Conditions ◽  
Spectrophotometric Methods ◽  
Fixed Quantity ◽  
Bulk Drug ◽  
Student’S T

Two sensitive spectrophotometric methods are described for the determination of simvastatin (SMT) in bulk drug and in tablets. The methods are based on the oxidation of SMT by a measured excess of cerium (IV) in acid medium followed by determination of unreacted oxidant by two different reaction schemes. In one procedure (method A), the residual cerium (IV) is reacted with a fixed concentration of ferroin and the increase in absorbance is measured at 510 nm. The second approach (method B) involves thereduction of the unreacted cerium (IV) with a fixed quantity of iron (II), and the resulting iron (III) is complexed with thiocyanate and the absorbance measured at 470 nm. In both methods, the amount of cerium (IV) reacted corresponds to SMT concentration. The experimental conditions for both methods were optimized. In method A, the absorbance is found to increase linearly with SMT concentration (r = 0.9995) whereas in method B, the same decreased (r = -0.9943). The systems obey Beer’s law for 0.6-7.5 and 0.5-5.0 μg mL-1 for method A and method B, respectively. The calculated molar absorptivity values are 2.7 X 104 and 1.06 X 105 Lmol-1 cm-1, respectively; and the corresponding sandel sensitivity values are 0.0153 and 0.0039μg cm-2, respectively. The limit of detection (LOD) and quantification (LOQ) are reported for both methods. Intra-day and inter-day precision, and accuracy of the methods were established as per the current ICH guidelines. The methods were successfully applied to the determination of SMT in tablets and the results were statistically compared with those of the reference method by applying the Student’s t-test and F-test. No interference was observed from the common excipients added to tablets. The accuracy and validity of the methods were further ascertained by performing recovery experiments via standard addition procedure.

scholarly journals Chlortetracycline-Functionalized Silver Nanoparticles as a Colorimetric Probe for Aminoglycosides: Ultrasensitive Determination of Kanamycin and Streptomycin

Nanomaterials ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 997 ◽  
Author(s):  
Ganesh Dattatraya Saratale ◽  
Rijuta Ganesh Saratale ◽  
Gajanan Ghodake ◽  
Surendra Shinde ◽  
Dae-Young Kim ◽  
...  
Keyword(s):  
Silver Nanoparticles ◽  
Color Change ◽  
Limit Of Detection ◽  
Colorimetric Assay ◽  
Uv Spectroscopy ◽  
Aminoglycoside Antibiotics ◽  
Sensing Element ◽  
Colorimetric Probe ◽  
Aqueous Conditions

Aminoglycosides (AMGs) have been extensively used to treat infectious diseases caused by Gram-negative bacteria in livestock and humans. A selective and sensitive colorimetric probe for the determination of streptomycin and kanamycin was proposed based on chlortetracycline-coated silver nanoparticles (AgNPs–CTC) as the sensing element. Almost all of the tested aminoglycoside antibiotics can rapidly induce the aggregation of AgNPs, along with a color change from yellow to orange/red. The selective detection of aminoglycoside antibiotics, including tobramycin, streptomycin, amikacin, gentamicin, neomycin, and kanamycin, with other types of antibiotics, can be achieved by ultraviolet (UV) spectroscopy. This developed colorimetric assay has ability to detect various AMGs using in-depth surface plasmon resonance (SPR) studies. With this determination of streptomycin and kanamycin was achieved at the picomolar level (pM) by using a UV–visible spectrophotometer. Under aqueous conditions, the linear range of the colorimetric sensor for streptomycin and kanamycin was 1000–1,1000 and 120–480 pM, respectively. The corresponding limit of detection was 2000 pM and 120 pM, respectively. Thus, the validated dual colorimetric and ratiometric method can find various analytical applications for the ultrasensitive and rapid detection of AMG antibiotics in water samples.

scholarly journals A High-Response Electrochemical As(III) Sensor Using Fe3O4–rGO Nanocomposite Materials

Chemosensors ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 150
Author(s):  
Haibing Hu ◽  
Wenjie Lu ◽  
Xingnan Liu ◽  
Fancheng Meng ◽  
Jianxiong Zhu
Keyword(s):  
Electron Microscopy ◽  
Glassy Carbon ◽  
Metal Ion ◽  
Electrochemical Impedance ◽  
Limit Of Detection ◽  
Detection Methods ◽  
Experimental Conditions ◽  
Water Field ◽  
Conductive Substrates ◽  
Higher Sensitivity

Nowadays, heavy metal ion pollution in water is becoming more and more common, especially arsenic, which seriously threatens human health. In this work, we used Fe3O4–rGO nanocomposites to modify a glassy carbon electrode and selected square wave voltametric electrochemical detection methods to detect trace amounts of arsenic in water. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) showed that Fe3O4 nanoparticles were uniformly distributed on the rGO sheet, with a particle size of about 20 nm. Raman spectroscopy and electrochemical impedance spectroscopy (EIS) showed that rGO provides higher sensitivity and conductive substrates. Under optimized experimental conditions, Fe3O4–rGO-modified glassy carbon electrodes showed a higher sensitivity (2.15 µA/ppb) and lower limit of detection (1.19 ppb) for arsenic. They also showed good selectivity, stability, and repeatability.

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 Aptamer-Conjugated Polydiacetylene Colorimetric Paper Chip for the Detection of Bacillus thuringiensis Spores

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3124
Author(s):  
Chaoge Zhou ◽  
Taeyeong You ◽  
Huisoo Jang ◽  
Hyunil Ryu ◽  
Eun-Seon Lee ◽  
...  
Keyword(s):  
Bacillus Thuringiensis ◽  
Polyvinylidene Fluoride ◽  
Color Change ◽  
Limit Of Detection ◽  
Paper Strip ◽  
High Concentration ◽  
Paper Chip ◽  
Pre Treatment ◽  
Pda Vesicles ◽  
Paper Sensor

A colorimetric polydiacetylene (PDA) paper strip sensor that can specifically recognize Bacillus thuringiensis (BT) HD-73 spores is described in this work. The target-specific aptamer was combined with PDA, and the aptamer-conjugated PDA vesicles were then coated on polyvinylidene fluoride (PVDF) paper strips by a simple solvent evaporation method. The PDA-aptamer paper strips can be used to detect the target without any pre-treatment. Using the paper strip, the presence of BT spores is directly observable by the naked eye based on the unique blue-to-red color transition of the PDA. Quantitative studies using the paper strip were also carried out by analyzing the color transitions of the PDA. The specificity of this PDA sensor was verified with a high concentration of Escherichia coli, and no discernable change was observed. The observable color change in the paper strip occurs in less than 1 h, and the limit of detection is 3 × 107 CFU/mL, much below the level harmful to humans. The PDA-based paper sensor, developed in this work, does not require a separate power or detection device, making the sensor strip highly transportable and suitable for spore analysis anytime and anywhere. Moreover, this paper sensor platform is easily fabricated, can be adapted to other targets, is highly portable, and is highly specific for the detection of BT spores.

scholarly journals Development of a new analytical spectroscopic methodology based on the competitive aggregation in a dye–surfactant–drug system: Application to the determination of gemfibrozil

2008 ◽  
Vol 22 (4) ◽  
pp. 309-317 ◽  
Author(s):  
Mohammad Amjadi ◽  
Jamshid L. Manzoori ◽  
Leila Farzampour
Keyword(s):  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Calibration Graph ◽  
Experimental Conditions ◽  
Analytical Methodology ◽  
Surfactant Aggregates ◽  
Didodecyldimethylammonium Bromide ◽  
The Difference ◽  
Absorption Features

A new analytical methodology based on the competitive aggregation in a dye–surfactant–drug system is developed for the determination of gemfibrozil. Eriochrome Blue Black R (EBBR) and Didodecyldimethylammonium bromide (DDABr) were the dye and surfactant used, respectively. In the proposed method, the anions of the dye bind to the cationic surfactant molecules to form dye–surfactant aggregates, which are monitored from changes in UV-Vis absorption features of the dye. In the ternary EBBR–DDABr–drug mixtures, the drug competes with the dye to interact with the surfactant, which results in a decrease in dye–surfactant aggregates formation. This, again, causes a change in absorption properties of the dye. The measurement parameter is the difference between the absorption of the dye in the presence and absence of the drug. In the appropriate experimental conditions the absorbance differences are directly proportional to the drug concentration. The influence of several experimental variables such as pH, concentrations of buffer, EBBR and DDABr on the measurement parameter were studied. Under the optimum conditions, the calibration graph was linear up to 6.0 μg ml−1with the correlation coefficient of 0.998. The limit of detection and quantification were found to be 0.044 and 0.15 μg ml−1, respectively. The method was validated and applied to the determination of gemfibrozil in pharmaceutical preparations.

scholarly journals Application of Derivative Spectrophotometry to Simultaneous Determination of Indomethacin and 5-Methoxy-2-methyl-3-indoleacetic Acid in Metindol Injections

2004 ◽  
Vol 87 (3) ◽  
pp. 592-595 ◽  
Author(s):  
Mariusz Stolarczyk ◽  
Jan Krzek ◽  
Włodzimierz Rzeszutko
Keyword(s):  
Simultaneous Determination ◽  
Indoleacetic Acid ◽  
Limit Of Detection ◽  
Accurate Method ◽  
Derivative Spectrophotometry ◽  
Experimental Conditions

Abstract Derivative spectrophotometry was employed to develop a rapid and accurate method for simultaneous determination of indomethacin and 5-methoxy-2-methyl-3-indoleacetic acid as its possible impurity in Metindol injections. At the selected wavelengths, 233.04 and 284.65 nm, no interference between the components determined was observed. Under the established experimental conditions, recoveries of the particular components were from 96.14 to 98.17%. Linearity was maintained over a broad range of concentrations, from 11.88 × 10−3 to 35.64 × 10−3 mg/mL for indomethacin and 0.4 to 1.2 mg/mL for 5-methoxy-2-methyl-3-indoleacetic acid. The limit of detection was found to be 6.0 × 10−3 mg/mL for indomethacin and 0.04 × 10−3 mg/mL for 5-methoxy-2-methyl-3-indoleacetic acid. The limits of quantitation were found to be 10.0 × 10−3 mg/mL and 0.20 × 10−3 mg/mL, respectively.

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