A Carbon Nanodots-Based Fluorescent Turn-On Probe for Iodide

2015 ◽  
Vol 68 (10) ◽  
pp. 1479 ◽  
Author(s):  
Qi Wang ◽  
Yuehuan Wu
Keyword(s):  
Limit Of Detection ◽  
Rapid Determination ◽  
Low Cost ◽  
Good Health ◽  
Food Chains ◽  
Carbon Nanodots ◽  
Competitive Reaction ◽  
Turn On ◽  
Excellent Selectivity

The human body requires iodine to develop and maintain proper metabolic balance. Worldwide, iodine deficiency affects two billion people and is the leading preventable cause of intellectual disability. Small amounts of iodine are needed for good health. However, large doses can eventually cause iodide goitre, hypothyroidism or myxedema. Children are especially sensitive to the effects of iodine. Because humans can be exposed to iodide via several different food chains, the development of on-site, real-time and reliable sensors for iodide is of great interest to ensure early diagnosis and improve management. We propose here a simple and low cost, yet sensitive and selective fluorescent ‘turn-off-on’ assay for rapid determination of iodide based on a combined carbon nanodots (CDs) and Hg2+ system. The fluorescence of CDs that was quenched by Hg2+ was restored and ‘turned on’ in the presence of iodide, which triggered a competitive reaction among CDs, Hg2+ and iodide. The recovered fluorescence intensity varied linearly with the concentration of iodide in the range of 0.05–5 μmol L–1, with a limit of detection as low as 46 nmol L–1. This approach shows excellent selectivity for iodine over the other anions.

scholarly journals Highly Luminescent and Biocompatible P and N Co-Doped Passivated Carbon Nanodots for the Sensitive and Selective Determination of Rifampicin Using the Inner Filter Effect

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2275 ◽  
Author(s):  
Baraa Al-Hashimi ◽  
Heshu Sulaiman Rahman ◽  
Khalid Mohammad Omer
Keyword(s):  
Limit Of Detection ◽  
Low Cost ◽  
Fluorescence Emission ◽  
Inner Filter Effect ◽  
Single Step ◽  
Carbon Nanodots ◽  
Pharmaceutical Dosage Forms ◽  
Selective Determination ◽  
Filter Effect

The determination of rifampicin in pharmaceutical dosage forms using a rapid, sensitive, selective, biocompatible, and low-cost method is of vital importance in the pharmaceutical analysis field to ensure its concentration is within the effective range when administered. In this study, nitrogen-and-phosphorous-doped carbon nanodots (CNDs) were prepared using a single-step hydrothermal method with ciprofloxacin as the starting material. The CNDs showed a highly intense blue fluorescence emission centered at 450 nm, with a photoluminescence quantum yield of about 51%. Since the absorption of rifampicin was the same as the excitation spectrum of CNDs, inner filter effect (IFE) quenching occurred and it was used as a successful detection platform for the analysis of rifampicin in capsules. The detection platform showed a dynamic linear range from 1 to 100 μM (R2 = 0.9940) and the limit of detection was 0.06 μM (when S/N = 3). The average spike recovery percentage for rifampicin in the capsule samples was 100.53% (n = 5). Moreover, the sub-chronic cytotoxicity of CNDs was evaluated on healthy male mice (Balb/c) drenched with different amounts of CNDs (10 and 50 mg/kg). During this study period, no mortalities or toxicity signs were recorded in any of the experimental subjects. Based on the cytotoxicity experiment, the proposed nano-probe is considered safe and biocompatible.

scholarly journals Miniaturized Fluorimetric Method for Quantification of Zinc in Dry Dog Food

2020 ◽  
Vol 2020 ◽  
pp. 1-6
Author(s):  
Rute C. Martins ◽  
Ana M. Pereira ◽  
Elisabete Matos ◽  
Luisa Barreiros ◽  
António J. M. Fonseca ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Rapid Determination ◽  
Low Cost ◽  
Food Samples ◽  
Dog Food ◽  
Fluorimetric Assay ◽  
Relative Standard ◽  
The Stability ◽  
Cost Determination

Zinc is an essential trace element for animals in several biological processes, particularly in energy production, and it is acquired from food ingestion. In this context, a microplate-based fluorimetric assay was developed for simple, fast, and low-cost determination of zinc in pet food using 2,2′-((4-(2,7-difluoro-3,6-dihydroxy-4aH-xanthen-9-yl)-3-methoxyphenyl)azanediyl)diacetic acid (FluoZin-1) as fluorescent probe. Several aspects were studied, namely, the stability of the fluorescent product over time, the FluoZin-1 concentration, and the pH of reaction media. The developed methodology provided a limit of detection of 1 μg L−1 in sample acid digests, with a working range of 10 to 200 μg L−1, corresponding to 100–2000 mg of Zn per kg of dry dog food samples. Intraday repeatability and interday repeatability were assessed, with relative standard deviation values < 3.4% (100 μg L−1) and <11.7% (10 μg L−1). Sample analysis indicated that the proposed fluorimetric assay provided results consistent with ICP-MS analysis. These results demonstrated that the developed assay can be used for rapid determination of zinc in dry dog food.

scholarly journals A Low Cost and Simple Lab-on-a-Chip for Spectrophotometric Determination of Ethanol

2017 ◽  
Vol 15 (7) ◽  
pp. 529-539
Author(s):  
Thanyaluck SOMSAENG ◽  
Kem PUMSA-ARD ◽  
Piyada JITTANGPRASERT
Keyword(s):  
Limit Of Detection ◽  
Rapid Determination ◽  
Low Cost ◽  
Colorimetric Detection ◽  
Lab On A Chip ◽  
Ceric Ammonium Nitrate ◽  
Alcoholic Beverages ◽  
Manufacturing Cost ◽  
Relative Standard

A simple lab-on-a-chip system was developed for the rapid determination of ethanol in different sample matrices, including gasohol and various alcoholic beverages. The colorimetric detection of ethanol using a spectrophotometer was based on the reaction between ethanol with 0.12 M ceric ammonium nitrate in acidic medium to produce a red colored product which gave a maximum absorption at 470 nm. A non-lithographic method was used for creating lab-on-a-chip molds to reduce  manufacturing cost and preparation steps. The lab-on-a-chip device was fabricated from polydimethylsiloxane which consisted of a simple Y-shaped working channel. Under optimum conditions, a linear calibration graph was obtained in the concentration range of 0.20 - 20 % (v/v) (r2> 0.999). The limit of detection (3 SD) and limit of quantification (10 SD) were 0.039 and 0.13 % (v/v), respectively. The precision reported in terms of relative standard deviation (RSD) values was less than 1.40 % (n = 15). To demonstrate the lab-on-a-chip’s performance, the determination of ethanol in gasohol and various alcoholic beverages was applied. The results obtained from the developed method compared with a standard gas chromatographic method were well correlated using the paired t-test and linear regression test. The results indicate that the proposed method has shown potential to extend the use of this simple lab-on-a-chip analytical device, due to its simplicity, low cost, lower reagent and sample consumption and high analytical performance. Moreover, the method of fabrication would be an additive manufacturing technique featuring a low equipment cost with no need for clean rooms.

UV-Visible Spectrophotometric Determination of Lambda-Cyhalothrin Insecticide in Vegetables, Soil and Water Samples

2019 ◽  
Vol 31 (1) ◽  
pp. 1-9
Author(s):  
Deepak Kumar Sahu ◽  
Joyce Rai ◽  
Chhaya Bhatt ◽  
Manish K. Rai ◽  
Jyoti Goswami ◽  
...  
Keyword(s):  
Crop Production ◽  
Limit Of Detection ◽  
Low Cost ◽  
Molar Absorptivity ◽  
Agricultural Field ◽  
Limit Of Quantification ◽  
Yellow Colour ◽  
Modern Age ◽  
Lambda Cyhalothrin

In modern age pesticide is used widely in agriculture. Lambda-cyhalothrin (LCT) is one of the most used pesticides which are used as a insecticide to kill pest, tricks, flies etc in agricultural field and it is also used for crop production. We have developed new method to detect LCT insecticide in agriculture field and reduce its uses. In this method we found the maximum absorbance at 460 nm for yellow colour dye. We also calculated limit of detection and limit of quantification 0.001 mg kg-1 and 0.056 mg kg-1 respectively. Molar absorptivity and Sandell’s sensitivity was also calculated and obtained 1.782 ×107 mol-1 cm-1 and 9.996 ×10-6 µg cm-2 respectively. The obtained yellow colour dye obeyed Beer’s law limit range of 0.5 µg ml -1 to 16 µg ml-1 in 25 ml. This method is less time consuming, selective, simple, sensitive and low cost. Present method is successfully applied in various soil, water and vegetable samples.

scholarly journals Rapid Determination of Cadmium Contamination in Lettuce Using Laser-Induced Breakdown Spectroscopy

Molecules ◽  
2018 ◽  
Vol 23 (11) ◽  
pp. 2930 ◽  
Author(s):  
Tingting Shen ◽  
Wenwen Kong ◽  
Fei Liu ◽  
Zhenghui Chen ◽  
Jingdong Yao ◽  
...  
Keyword(s):  
Limit Of Detection ◽  
Rapid Determination ◽  
Univariate Analysis ◽  
Laser Induced Breakdown Spectroscopy ◽  
Growth Environment ◽  
Breakdown Spectroscopy ◽  
Contamination Degree ◽  
Cd Contamination ◽  
Laser Induced Breakdown

Quick access to cadmium (Cd) contamination in lettuce is important to supervise the leafy vegetable growth environment and market. This study aims to apply laser-induced breakdown spectroscopy (LIBS) technology for fast determination of Cd content and diagnosis of the Cd contamination degree in lettuce. Emission lines Cd II 214.44 nm, Cd II 226.50 nm, and Cd I 228.80 nm were selected to establish the univariate analysis model. Multivariate analysis including partial least squares (PLS) regression, was used to establish Cd content calibration models, and PLS model based on 22 variables selected by genetic algorithm (GA) obtained the best performance with correlation coefficient in the prediction set Rp2 = 0.9716, limit of detection (LOD) = 1.7 mg/kg. K-Nearest Neighbors (KNN) and random forest (RF) were used to analyze Cd contamination degree, and RF model obtained the correct classification rate of 100% in prediction set. The preliminary results indicate LIBS coupled with chemometrics could be used as a fast, efficient and low-cost method to assess Cd contamination in the vegetable industry.

scholarly journals Preparation of Cerium Oxide-MWCNTs Nanocomposite Bulk Modified Carbon Ceramic Electrode: A Sensitive Sensor for Tamoxifen Determination in Human Serum Samples

2021 ◽  
Author(s):  
Sepideh Shafaei ◽  
Elyas Hosseinzadeh ◽  
Gulsah Saydan Kanberoglu ◽  
Balal Khalilzadeh ◽  
Rahim Mohammad-Rezaei
Keyword(s):  
Cerium Oxide ◽  
Limit Of Detection ◽  
Low Cost ◽  
High Electron ◽  
Range Limit ◽  
Serum Samples ◽  
Important Species ◽  
Carbon Ceramic Electrode ◽  
Carbon Ceramic

Abstract In this study, cerium oxide and multi-walled carbon nanotubes nanocomposite was incorporated into the carbon ceramic electrode (CeO2-MWCNTs/CCE) as a renewable electrode for the electrocatalytic purposes. To demonstrate capability of the fabricated electrode, determination of Tamoxifen as an important anticancer drug with differential pulse voltammetry technique was evaluated. Linear range, limit of detection and sensitivity of the developed sensor were found to be 0.2-40 nM, 0.132 nM and 1.478 µA nM-1 cm-2, respectively. Ease of production, low cost and high electron transfer rate of CeO2-MWCNTs/CCE promise it as a novel electro-analytical tool for determination of important species in real samples.

scholarly journals A Simple, Rapid, Fluorometric Assay for Dopamine by In Situ Reaction of Boronic Acids and cis-Diol

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaoxia Liu ◽  
Miaomiao Tian ◽  
Wenmei Gao ◽  
Jinzhong Zhao
Keyword(s):  
Low Cost ◽  
Boronic Acids ◽  
Emission Peak ◽  
Excitation Wavelength ◽  
Fluorescence Sensing ◽  
Serum Samples ◽  
Turn On ◽  
Rapid Reaction

An efficient, sensitive, and low-cost method has been developed for turn-on fluorescence sensing of dopamine (DA). The method relies on the rapid reaction of DA and 3-Hydroxyphenylboronic acid (3-HPBA) via specific recognition between boronic acids and cis-diol of DA in alkaline solution. The reaction product shows an excitation wavelength of 417 nm and the maximum emission peak at 470 nm. The proposed method allows the determination of DA in the range of 50 nM–25 μM, and the whole detection can be completed within 5 minutes. Furthermore, the presented approach has good selectivity and has been successfully applied to DA sensing in human serum samples, showing great potential in clinical diagnosis.

scholarly journals Rapid Determination of Lysine in Biological Samples by Isocratic Liquid Chromatography

1999 ◽  
Vol 82 (4) ◽  
pp. 809-813 ◽  
Author(s):  
Mamun M Or-Rashid ◽  
Ryoji Onodera ◽  
Shaila Wadud ◽  
Mohamed-Emad A Nasser ◽  
Mohammad R Amin
Keyword(s):  
Liquid Chromatography ◽  
Biological Samples ◽  
Limit Of Detection ◽  
Rapid Determination ◽  
Rumen Fluid ◽  
Uv Detector ◽  
Rumen Microorganisms ◽  
Microbial Nitrogen ◽  
Limit Of Quantitation

Abstract A simple, rapid, and sensitive method was developed for detection and quantitation of lysine (Lys) in various biological samples by isocratic liquid chromatography (LC). Samples containing Lys and other amino acids were derivatized with 9-fluorenylmethyl chloroformate (FMOC-CI). The mobile phase used for isocratic elution was 50 mmol/L sodium acetate buffer (pH 4.20)-acetonitrile (43 + 57, v/v). Lys was detected with a UV detector at 265 nm. The derivatized Lys eluted from a LiChrospher 100 RP-18 (150× 4.0 mm id) column at a retention time of 5.6 min. The limit of detection was 0.73 μmol/L (signal-to-noise [S/N] ratio, 3:1), and the limit of quantitation was 2.37 μmol/L (S/N ratio, 10:1). Lys recoveries from fortified biological samples were &gt;97.5%. Average Lys contents found in rumen fluid samples collected before the morning feeding and at 2.0,4.0, and 6.0 h after feeding were 4.26,3.34,3.58, and 3.82 μmol/L, respectively. The hydrolysate of a sample of mixed rumen microorganisms collected before the morning feeding was determined to contain 1.372 μmol/mg microbial nitrogen in the form of Lys. The Lys concentrations of human plasma, goat plasma, human urine, and goat urine were 140.0, 102.0,58.0, and 32.0 μmol/L, respectively.

scholarly journals An Improved Method for Analysis of Cholecalciferol-Treated Baits

1999 ◽  
Vol 82 (4) ◽  
pp. 792-798
Author(s):  
Richard E Mauldin ◽  
John J Johnston ◽  
Craig A Riekena
Keyword(s):  
Extraction Method ◽  
Limit Of Detection ◽  
Rapid Determination ◽  
Liquid Extraction ◽  
Detector Response ◽  
Improved Method ◽  
Standard Curve ◽  
Time Periods ◽  
Precision And Accuracy

Abstract A liquid extraction method is described that permits rapid determination of cholecalciferol (D3) in rodenticidal grain baits. Purified D3 was incubated for various time periods to produce pre-D3. Response ratios (concentration/detector response) for various concentrations of pre-D3 and D3 in solutions permitted generation of a correction factor for direct quantitation of pre-D3 in solutions with a pure D3 standard. The method has equal precision and accuracy, yet is simpler and less time consuming and requires less solvents than widely accepted methods for extracting D3 from grain baits. Recoveries from control oat baits fortified at 0.05 and 0.75 wt% were 100.9 and 98%, respectively. A standard curve for concentrations ranging from 6.4 to 204 μg/mL had an r2 of 0.9999 and an intercept of zero and was linear and proportional. The method limit of detection was 2.0 × 10−4 wt % D3.

scholarly journals Rapid and Sensitive Spectrophotometric Method for the Determination of the Trace Amount of Thallium (III) in Water and Urine Samples by New Oxidative Coupling Reaction

2019 ◽  
Vol 53 (4) ◽  
Author(s):  
Padmarajaiah Nagaraja ◽  
Naef Ghllab Saeed Al-Tayar ◽  
Anantharaman Shivakumar ◽  
Ashwinee Kumar Shresta ◽  
Avinash K. Gowda
Keyword(s):  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Rapid Determination ◽  
Coupling Reaction ◽  
Molar Absorptivity ◽  
Urine Samples ◽  
Oxidative Coupling Reaction ◽  
Relative Standard ◽  
Student’S T

A very simple, sensitive and fairly selective direct spectrophotometric method is presented for the rapid determination of thallium(III) at trace level. The method is based on the oxidation of 2-hydrazono-3-methyl-2,3-dihydrobenzo[d]thiazole hydrochloride (MBTH) by thallium(III) in phosphoric acid medium to form a diazoniumcation, which couples immediately with 10,11-dihydro-5Hdibenzo[b,f]azepine (IDB) at room temperature giving a blue colored species having a maximum absorption at 660 nm. The reaction conditions and other important analytical parameters were optimized.The calibration curve was found to be linear over the range of 0.1-4 μg/mL with molar absorptivity of 4.5 × 104 L mol- cm-1 and Sandell’s sensitivity of 0.00454 μg cm-2. The relative standard deviation and limit of detection have been found to be 0.58% and 0.0147 μg/mL respectively. Almost all common anions and cations are found notto interfering in matrix level of the analytical process. The method has been successfully applied for the determination of thallium(III) in synthetic standard mixtures, water and human urine samples. The performance of proposed method was evaluated in terms of student’s t-test and variance ratio F-test, to find out the significance of proposed method over the reported methods.    

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