scholarly journals Electrochemical Approach to Detection of Chlorophene in Water Catalyzed by a Laccase Modified Gold Electrode

Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 82
Author(s):  
Gabriela Elizabeth Quintanilla-Villanueva ◽  
Donato Luna-Moreno ◽  
Araceli Sánchez-Álvarez ◽  
Juan Francisco Villarreal-Chiu ◽  
José Manuel Rodríguez-Delgado ◽  
...  
Keyword(s):  
Water Samples ◽  
Detection Method ◽  
Matrix Effects ◽  
Limit Of Detection ◽  
Reference Method ◽  
Health And Environmental Effects ◽  
Recognition Element ◽  
Electrochemical Parameters ◽  
Electrochemical Approach ◽  
Recovery Percentage

Despite the increasing number of reports that relate antimicrobial chlorophene (CP) with health and environmental effects, few studies have addressed biosensing technologies to detect this threat. This work proposed an electrochemical approach for the detection of CP using laccase enzymes as an alternative recognition element immobilized onto thin-film gold electrodes. The electrochemical parameters of the detection method, under controlled conditions, resulted in a limit of detection (0.14 ± 0.06 mg L−1) and quantification (0.48 ± 0.04 mg L−1) that agreed with concentrations of CP that already had been measured in natural water samples. Nevertheless, during the analysis of natural river water samples, the provided method suffered a drawback due to matrix effects reflected in the obtained recovery percentage, the value of which was 62.0 ± 2.4% compared to the 101.3 ± 3.5% obtained by the HPLC reference method. These detrimental effects were mainly attributed to organic matter, SO4-2, and Cl- present in river samples.

scholarly journals The Potential Use of a Thin Film Gold Electrode Modified with Laccases for the Electrochemical Detection of Pyrethroid Metabolite 3-Phenoxybenzaldehyde

Materials ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 1992
Author(s):  
Verónica Aglaeé Esquivel-Blanco ◽  
Gabriela Elizabeth Quintanilla-Villanueva ◽  
Juan Francisco Villarreal-Chiu  ◽  
José Manuel Rodríguez-Delgado ◽  
Melissa Marlene Rodríguez-Delgado
Keyword(s):  
Thin Film ◽  
Gold Electrode ◽  
Limit Of Detection ◽  
Infrared Spectrometry ◽  
Natural Environments ◽  
Direct Oxidation ◽  
Recognition Element ◽  
Electrochemical Parameters ◽  
Electrochemical Approach ◽  
Pyrethroid Pesticides

There is increasing interest in developing portable technologies to detect human health threats through hybrid materials that integrate specific bioreceptors. This work proposes an electrochemical approach for detecting 3-Phenoxybenzaldehyde (3-PBD), a biomarker for monitoring human exposure to pyrethroid pesticides. The biosensor uses laccase enzymes as an alternative recognition element by direct oxidation of 3-PBD catalysts by the enzyme onto thin-film gold electrodes. The thin-film gold electrode modified by the immobilized laccase was characterized by Fourier-transform infrared spectrometry and scanning electron microscopy. The detection method’s electrochemical parameters were established, obtaining a linear range of 5 t 50 μM, the limit of detection, and quantification of 0.061 and 2.02 μM, respectively. The proposed biosensor’s analytical performance meets the concentration of pyrethroids detected in natural environments, reflecting its potential as an alternative analytical tool for monitoring the pyrethroid insecticide’s presence.

scholarly journals A Novel Enzyme-Based SPR Strategy for Detection of the Antimicrobial Agent Chlorophene

Biosensors ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 43 ◽  
Author(s):  
Gabriela Elizabeth Quintanilla-Villanueva ◽  
Donato Luna-Moreno ◽  
Edgar Allan Blanco-Gámez ◽  
José Manuel Rodríguez-Delgado ◽  
Juan Francisco Villarreal-Chiu ◽  
...  
Keyword(s):  
Antimicrobial Agent ◽  
Matrix Effects ◽  
Limit Of Detection ◽  
Direct Detection ◽  
Covalent Immobilization ◽  
Hplc Method ◽  
Health And Environmental Effects ◽  
Recognition Element ◽  
Emerging Pollutant ◽  
Significant Difference

Chlorophene is an important antimicrobial agent present in disinfectant products which has been related to health and environmental effects, and its detection has been limited to chromatographic techniques. Thus, there is a lack of research that attempts to develop new analytical tools, such as biosensors, that address the detection of this emerging pollutant. Therefore, a new biosensor for the direct detection of chlorophene in real water is presented, based on surface plasmon resonance (SPR) and using a laccase enzyme as a recognition element. The biosensor chip was obtained by covalent immobilization of the laccase on a gold-coated surface through carbodiimide esters. The analytical parameters accomplished resulted in a limit of detection and quantification of 0.33 mg/L and 1.10 mg/L, respectively, fulfilling the concentrations that have already been detected in environmental samples. During the natural river’s measurements, no significant matrix effects were observed, obtaining a recovery percentage of 109.21% ± 7.08, which suggested that the method was suitable for the fast and straightforward analysis of this contaminant. Finally, the SPR measurements were validated with an HPLC method, which demonstrated no significant difference in terms of precision and accuracy, leading to the conclusion that the biosensor reflects its potential as an alternative analytical tool for the monitoring of chlorophene in aquatic environments.

scholarly journals Evaluation of a Stable Isotope-Based Direct Quantification Method for Dicamba Analysis from Air and Water Using Single-Quadrupole LC–MS

Molecules ◽  
2020 ◽  
Vol 25 (16) ◽  
pp. 3649 ◽  
Author(s):  
Manoj Ghaste ◽  
Nicholas C. Hayden ◽  
Matthew J. Osterholt ◽  
Julie Young ◽  
Bryan Young ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Water Samples ◽  
Detection Method ◽  
Matrix Effects ◽  
Solid Phase ◽  
Internal Standard ◽  
Sample Collection ◽  
Selected Ion Monitoring ◽  
Ms Detection ◽  
Direct Quantification

Dicamba is a moderately volatile herbicide used for post-emergent control of broadleaf weeds in corn, soybean, and a number of other crops. With increased use of dicamba due to the release of dicamba-resistant cotton and soybean varieties, growing controversy over the effects of spray drift and volatilization on non-target crops has increased the need for quantifying dicamba collected from water and air sampling. Therefore, this study was designed to evaluate stable isotope-based direct quantification of dicamba from air and water samples using single-quadrupole liquid chromatography–mass spectrometry (LC–MS). The sample preparation protocols developed in this study utilize a simple solid-phase extraction (SPE) protocol for water samples and a single-step concentration protocol for air samples. The LC–MS detection method achieves sensitive detection of dicamba based on selected ion monitoring (SIM) of precursor and fragment ions and relies on the use of an isotopically labeled internal standard (IS) (D3-dicamba), which allows for calculating recoveries and quantification using a relative response factor (RRF). Analyte recoveries of 106–128% from water and 88–124% from air were attained, with limits of detection (LODs) of 0.1 ng mL−1 and 1 ng mL−1, respectively. The LC–MS detection method does not require sample pretreatment such as ion-pairing or derivatization to achieve sensitivity. Moreover, this study reveals matrix effects associated with sorbent resin used in air sample collection and demonstrates how the use of an isotopically labeled IS with RRF-based analysis can account for ion suppression. The LC–MS method is easily transferrable and offers a robust alternative to methods relying on more expensive tandem LC–MS/MS-based options.

scholarly journals Preconcentration of Chromium(VI) at Trace Levels Using Acid Alumina Resin with Column Method

2014 ◽  
Vol 14 (1) ◽  
pp. 51-56 ◽  
Author(s):  
Aman Sentosa Panggabean ◽  
Subur P Pasaribu ◽  
Bohari Bohari ◽  
Nurhasanah Nurhasanah
Keyword(s):  
Water Samples ◽  
Trace Analysis ◽  
Limit Of Detection ◽  
Analytical Performance ◽  
Filler Material ◽  
Retention Capacity ◽  
Line Method ◽  
Chromium Vi ◽  
Column Method ◽  
Recovery Percentage

Trace analysis of Chromium(VI) ions using acid alumina resin as a filler material column in preconcentration system by off-line method has been carried out. Alumina resin was activated with H2SO4 at pH 1 before being filled to the column. This research showed retention capacity of alumina acid resin was 3.955 mg Cr(VI)/g resin. The analytical performance of this method is good, shown with the limit of detection value was 3.648 µg/L. The reproducibility of this method shown as percentage of coefficient variance was 2.06%. Acid alumina used as resin filler column can increase the signal up to 15.36 times for direct Cr(VI) ions measurement. The accuracy of this method is very good with the recovery percentage value > 95%, shown the matrices of water samples didn’t effect the results of measurements and this method was capable to analyze Cr(VI) ions in water samples at the trace levels.

scholarly journals Detection of Active BoNT/C and D by EndoPep-MS Using MALDI Biotyper Instrument and Comparison with the Mouse Test Bioassay

Toxins ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 10
Author(s):  
Ilenia Drigo ◽  
Elena Tonon ◽  
Simone Pascoletti ◽  
Fabrizio Anniballi ◽  
Suzanne R. Kalb ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Animal Health ◽  
Lethal Dose ◽  
Reference Method ◽  
Mouse Bioassay ◽  
Peptide Fragments ◽  
Mass Spectrometers ◽  
Detection And Identification ◽  
Maldi Biotyper ◽  
Sensitivity Specificity

Botulinum neurotoxins (BoNTs) are among the most poisonous known biological substances, and therefore the availability of reliable, easy-to use tools for BoNT detection are important goals for food safety and human and animal health. The reference method for toxin detection and identification is the mouse bioassay (MBA). An EndoPep-MS method for BoNT differentiation has been developed based on mass spectrometry. We have validated and implemented the EndoPep-MS method on a Bruker MALDI Biotyper for the detection of BoNT/C and D serotypes. The method was extensively validated using experimentally and naturally contaminated samples comparing the results with those obtained with the MBA. Overall, the limit of detection (LoD) for both C and D toxins were less than or equal to two mouse lethal dose 50 (mLD50) per 500 µL for all tested matrices with the exception of feces spiked with BoNT/C which showed signals not-related to specific peptide fragments. Diagnostic sensitivity, specificity and positive predictive value were 100% (95% CI: 87.66–100%), 96.08% (95% CI: 86.54–99.52%), and 93.33% (95% CI: 78.25–98.20%), respectively, and accuracy was 97.47% (95% CI: 91.15–99.69%). In conclusion, the tests carried out showed that the EndoPep-MS method, initially developed using more powerful mass spectrometers, can be applied to the Bruker MALDI Biotyper instrument with excellent results including for detection of the proteolytic activity of BoNT/C, BoNT/D, BoNT/CD, and BoNT/DC toxins.

scholarly journals Immobilization-Free Electrochemical Sensor Coupled with a Graphene-Oxide-Based Aptasensor for Glycated Albumin Detection

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 85
Author(s):  
Wassa Waiwinya ◽  
Thitirat Putnin ◽  
Dechnarong Pimalai ◽  
Wireeya Chawjiraphan ◽  
Nuankanya Sathirapongsasuti ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Electrochemical Sensor ◽  
Detection Method ◽  
Limit Of Detection ◽  
Glycated Albumin ◽  
Cost Effective ◽  
Logarithmic Scale ◽  
Electrochemical Aptasensor ◽  
Alternative Approach

An immobilization-free electrochemical sensor coupled with a graphene oxide (GO)-based aptasensor was developed for glycated human serum albumin (GHSA) detection. The concentration of GHSA was monitored by measuring the electrochemical response of free GO and aptamer-bound GO in the presence of glycated albumin; their currents served as the analytical signals. The electrochemical aptasensor exhibited good performance with a base-10 logarithmic scale. The calibration curve was achieved in the range of 0.01–50 µg/mL. The limit of detection (LOD) was 8.70 ng/mL. The developed method was considered a one-drop measurement process because a fabrication step and the probe-immobilization process were not required. This simple sensor offers a cost-effective, rapid, and sensitive detection method, and could be an alternative approach for determination of GHSA levels.

scholarly journals Perchlorate Levels in Polish Water Samples of Various Origin

Separations ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 37
Author(s):  
Przemysław Niziński ◽  
Patrycja Wiśniewska ◽  
Joanna Kończyk ◽  
Rajmund Michalski
Keyword(s):  
Drinking Water ◽  
Water Samples ◽  
Limit Of Detection ◽  
Primary Objective ◽  
Swimming Pool ◽  
Limit Of Quantification ◽  
Reliable Determination ◽  
Pool Water ◽  
Drinking Waters ◽  
Swimming Pool Water

Perchlorate ion (ClO4−) is known as a potent endocrine disruptor and exposure to this compound can result in serious health issues. It has been found in drinking water, swimming pools, and surface water in many countries, however, its occurrence in the environment is still poorly understood. The information on perchlorate contamination of Polish waters is very limited. The primary objective of this study was to assess ClO4− content in bottled, tap, river, and swimming pool water samples from different regions of Poland and provide some data on the presence of perchlorate. We have examined samples of bottled, river, municipal, and swimming pool water using the IC–CD (ion chromatography–conductivity detection) method. Limit of detection and limit of quantification were 0.43 µg/L and 1.42 µg/L, respectively, and they were both above the current health advisory levels in drinking water. The concentration of perchlorate were found to be 3.12 µg/L in one river water sample and from 6.38 to 8.14 µg/L in swimming pool water samples. Importantly, the level of perchlorate was below the limit of detection (LOD) in all bottled water samples. The results have shown that the determined perchlorate contamination in Polish drinking waters seems to be small, nevertheless, further studies are required on surface and river samples. The inexpensive, fast, and sensitive IC–CD method used in this study allowed for a reliable determination of perchlorate in the analyzed samples. To the best of our knowledge, there are no other studies seeking to assess the perchlorate content in Polish waters.

Assessment of a Semiquantitative Liquid Chromatography- Fluorescence Detection Method for the Determination of Paralytic Shellfish Poisoning Toxin Levels in Bivalve Molluscs from Great Britain

2014 ◽  
Vol 97 (2) ◽  
pp. 492-497 ◽  
Author(s):  
Andrew D Turner ◽  
Monika Dhanji-Rapkova ◽  
Clothilde Baker ◽  
Myriam Algoet
Keyword(s):  
Great Britain ◽  
Fluorescence Detection ◽  
Detection Method ◽  
Reference Method ◽  
Paralytic Shellfish Poisoning ◽  
Official Method ◽  
Shellfish Poisoning ◽  
Bivalve Molluscs ◽  
Paralytic Shellfish

Abstract AOAC Official Method 2005.06 precolumn oxidation LC-fluorescence detection method has been used for many years for the detection and quantitation of paralytic shellfish poisoning (PSP) toxins in bivalve molluscs. After extensive single- and multiple-laboratory validation, the method has been slowly gaining acceptance worldwide as a useful and practical tool for official control testing. In Great Britain, the method has become routine since 2008, with no requirement since then for reverting back to the bioassay reference method. Although the method has been refined to be semiautomated, faster, and more reproducible, the quantitation step can be complex and time-consuming. An alternative approach was developed to utilize the qualitative screening results for generatinga semiquantitative results assessment. Data obtained over 5 years enabled the comparison of semiquantitative and fully quantitative PSP results in over 15 000 shellfish samples comprising eight different species showed that the semiquantitative approach resulted in over-estimated paralytic shellfish toxin levels by an average factor close to two in comparison with the fully quantified levels. No temporal trends were observed in the data or relating to species type, with the exception of surf clams. The comparison suggested a semiquantitative threshold of 800 μg saxitoxin (STX) eq/kg should provide a safe limitfor the determination of samples to be forwarded to full quantitation. However, the decision was taken to halve this limit to include an additional safety factor of 2, resulting in the use of a semiquantitative threshold of 400 μg STX eq/kg. Implementation of the semiquantitative method into routine testing would result in a significant reduction in the numbers of samples requiring quantitation and have a positive impact on the overall turnaround of reported PSP results. The refined method would be appropriate for any monitoring laboratory faced with high throughput requirements.

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 Spectrophotometric Determination of Zidovudine in Pharmaceuticals Based on Charge-Transfer Complexation Involving N-Bromosuccinimide, Metol and Sulphanilic Acid as Reagents

2007 ◽  
Vol 4 (2) ◽  
pp. 173-179 ◽  
Author(s):  
K. Basavaiah ◽  
U. R. Anil Kumar
Keyword(s):  
Limit Of Detection ◽  
Pharmaceutical Preparations ◽  
Reference Method ◽  
Standard Addition ◽  
Molar Absorptivity ◽  
Sulphanilic Acid ◽  
Bulk Drug ◽  
Student’S T ◽  
Charge Transfer Complexation

A simple spectrophotometric method is proposed for the determination of zidovudine(ZDV) in bulk drug and in pharmaceutical preparations. The method is based on the oxidation of ZDV by a known excess of oxidant N-bromosuccinimide (NBS), in buffer medium of pH 1.5, followed by the estimation of unreacted amount of oxidant with metol and sulphanilic acid. The reacted oxidant corresponds to the amount ZDV. The purple-red reaction product absorbs maximally at 530 nm and Beer’s law is obeyed over a range 5 to 75 μg mL-1. The apparent molar absorptivity is calculated to be 5.1×103L mol-1cm-1, and the corresponding Sandell sensitivity value is 0.052 μg cm-2. The limit of detection and quantification are found to be 0.90 and 2.72, respectively. Intra-day and inter-day precision and accuracy of the developed methods were evaluated as per the current ICH guidelines. The method was successfully applied to the assay of ZDV in tablet/capsule preparations 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 tablet/capsule excipients. The accuracy of the method was further ascertained by performing recovery studies via standard-addition method.

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