scholarly journals Carbon Dot Functionalized Papers for the Selective Detection of 2,4,6-Trinitrophenol in Aqueous Solutions

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Wenli Peng ◽  
Li Gan ◽  
Weihan Li ◽  
Shixiong Deng
Keyword(s):  
Aqueous Solutions ◽  
Carbon Dots ◽  
Detection Method ◽  
Tap Water ◽  
Raw Material ◽  
Fluorescence Quench ◽  
Relative Standard ◽  
Promising Application ◽  
Good Linear Correlation

The development of probes for the testing of the carcinogenic pollutant 2,4,6-trinitrophenol (TNP) is of great importance for environmental protection and human health. In this paper, a new rapid and sensitive fluorescence detection method based on carbon dots (CDs) was designed for the detection of TNP. The CDs were synthesized by simple pyrolysis using citric acid as raw material and characterized by various advanced techniques. The addition of TNP caused a significant turn off in the fluorescence of the CDs. The fluorescence quench intensity and TNP concentration exhibited a good linear correlation in the range of 0–80 μM with a minimum detection limit of 0.48 μM and a related coefficient of 0.994. The analytical method was applied to the determination of trace TNP in river water and tap water with recoveries in the range of 98%–110% and relative standard deviations less than 5%. Importantly, carbon dots functionalized papers (CDFPs) were prepared using the synthesized CDs and successfully applied to the determination of TNP in aqueous solutions, demonstrating the promising application of the method.

scholarly journals Development of a New High-Performance Liquid Chromatographic Method for the Determination of Ceftazidime

2008 ◽  
Vol 91 (4) ◽  
pp. 739-743 ◽  
Author(s):  
Andréia de Haro Moreno ◽  
Hérida Regina Nunes Salgado
Keyword(s):  
High Performance ◽  
High Performance Liquid Chromatographic ◽  
Reversed Phase ◽  
Hplc Method ◽  
Calibration Graph ◽  
Raw Material ◽  
Relative Standard ◽  
Validation Parameters ◽  
Liquid Chromatographic

Abstract A rapid, accurate, and sensitive high-performance liquid chromatographic (HPLC) method was developed and validated for the determination of ceftazidime in pharmaceuticals. The method validation parameters yielded good results and included range, linearity, precision, accuracy, specificity, and recovery. The excipients in the commercial powder for injection did not interfere with the assay. Reversed-phase chromatography was used for the HPLC separation on a Waters C18 (WAT 054275; Milford, MA) column with methanolwater (70 + 30, v/v) as the mobile phase pumped isocratically at a flow rate of 1.0 mL/min. The effluent was monitored at 245 nm. The calibration graph for ceftazidime was linear from 50.0 to 300.0 g/mL. The values for interday and intraday precision (relative standard deviation) were <1. The results obtained by the HPLC method were calculated statistically by analysis of variance. We concluded that the HPLC method is satisfactory for the determination of ceftazidime in the raw material and pharmaceuticals.

scholarly journals Determination of Se4+ in Drinkable Water by Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry

2000 ◽  
Vol 83 (5) ◽  
pp. 1082-1086 ◽  
Author(s):  
Maurizio Guidotti
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Tap Water ◽  
Gas Chromatography Mass Spectrometry ◽  
Chromatography Mass Spectrometry ◽  
Relative Standard ◽  
Drinkable Water

Abstract A method was developed for the selective determination of Se4+ in drinkable water by solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS). Se4+ was selectively derivatized to ethane, 1,1′-selenobis by reaction with sodium tetraethylborate, extracted by the SPME fiber, and determined by GC/MS. Both headspace (HS)–SPME and direct SPME were studied. The method requires only a few milliliters of sample and 20 min for completion. At 2.0 μg/L concentration, the relative standard deviation was 10.1% for HS–SPME and 9.1% for direct SPME. For HS–SPME, the theoretical detection limit was 81 ng/L and 166 ng/L for direct SPME. The recovery rate was 95%. The method was used to determine Se4+ in 10 tap water samples.

Cloud Point Extraction and Spectrophotometry Determination of Lead in Environment Water Using 5-Br-PADAP

2013 ◽  
Vol 830 ◽  
pp. 345-348
Author(s):  
Lin Gao ◽  
Sheng Jie Chen ◽  
Fang Chen ◽  
Wen Hong Zhou ◽  
Jun Long Yao
Keyword(s):  
Cloud Point ◽  
Cloud Point Extraction ◽  
Detection Method ◽  
Low Cost ◽  
Calibration Graph ◽  
Buffer Solution ◽  
Relative Standard ◽  
Triton X ◽  
Optimized Conditions

A simple, sensitive, green and low cost detection method based on the cloud point extraction (CPE) separation and spectrophotometry was proposed for the determination of lead. In pH=9.0 H3BO3 buffer solution, Pb(II) reacts with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) in the presence of Triton X-100 yielding a hydrophobic complex, which then is extracted into micro-volume surfactant-rich phase. The calibration graph was linear in the range of 20-400 µg/L (at 560 nm). Under the optimized conditions, the detection limits of 10.94 µg/L and the relative standard deviations(RSD) of 2.0% (n=5) for Lead(II) were found, respectively. The sensitivity and absorbance of this method are at least five times higher when compared with that of usual 5-Br-PADAP spectrophotometry without CPE, and the proposed method has been applied to the determination of Lead in environment water samples with satisfactory results.

An improved method for determining HNMs in drinking water

2013 ◽  
Vol 13 (5) ◽  
pp. 1257-1264 ◽  
Author(s):  
F. Q. Huang ◽  
M. Y. Ruan ◽  
J. D. Yan ◽  
H. C. Hong ◽  
H. J. Lin ◽  
...  
Keyword(s):  
Drinking Water ◽  
Extraction Efficiency ◽  
Tap Water ◽  
Correlation Coefficients ◽  
Method Detection Limit ◽  
Good Reliability ◽  
Liquid Liquid Extraction ◽  
Relative Standard ◽  
Water Ph

Halonitromethanes (HNMs) in drinking water are increasingly becoming a public concern due to their high health risks, so development of a sensitive method for their analysis has become a priority. Liquid–liquid extraction (LLE) method is dominantly used in current studies regarding HNMs. However the sensitivity is far from ideal. The present study aims to investigate the factors that may influence the extraction efficiency during HNM analysis by LLE method, and as a result develop a more sensitive extraction method for HNM determination. Results showed that the dose of sodium sulfate exerted the most significant influence, followed by copper sulfate, while the pH and manual shaking times have little effect. Under the suitable conditions (for extracting HNMs in 45 mL water: pH = 3.5–5, CuSO4 = 1.0 g, Na2SO4 = 6 g, shaking times = 120–180), the correlation coefficients (r) of the calibration curves for nine HNMs were all more than 0.9925. The method detection limit (MDL) ranged from 0.017 to 0.217 μg L−1 with an average of 0.076 μg L−1, which was dominantly lower than the method reported. The recovery (spiked blank samples: 98–108%; spiked tap water: 81–120%) and precision (relative standard deviation: 0.46–6.72) also showed good reliability and reproducibility of the method. Finally, the developed method was applied to the determination of HNMs in real water samples.

scholarly journals A Terbium Sensitized Luminescence Method for the Assay of Flubiprofen in Pharmaceutical Formulations

2014 ◽  
Vol 19 (1) ◽  
pp. 54
Author(s):  
Salma M.Z. Al-Kindy ◽  
Arwa Al-Ghazali ◽  
Fakhr Eldin O. Suliman ◽  
Haidar A.J. Al-Lawati
Keyword(s):  
Limit Of Detection ◽  
Tap Water ◽  
Pharmaceutical Formulations ◽  
Aqueous System ◽  
Tween 20 ◽  
Luminescence Method ◽  
Time Resolved ◽  
Relative Standard ◽  
Excellent Reproducibility

A sensitive time-resolved luminescence method for the determination of flubiprofen (FLP) in methanol and in aqueous solution is described. The method is based on the luminescence sensitization of terbium (Tb3+ ) by the formation of a ternary complex with FLP in the presence of 4,7 diphenyl 1,10 phenanthroline (DPP) as co-ligand, and Tween-20 as surfactant. The signal for Tb-FLP-DPP was monitored at λex  = 285 nm and λem  = 552 nm. Optimum conditions for the formation of the complex in an aqueous system were TRIS buffer, pH 8.0, DPP (2.5Å~10−7  M), Tween-20 (0.30%) and 4Å~10-5  mol L-1  of Tb3+  which allowed the determination of 20–1000 ng mL-1  of FLP with a limit of detection (LOD) of 10 ng mL-1 . The relative standard deviations of the method ranged between 0.6 and 1.4% indicating excellent reproducibility of the method. The proposed method was successfully applied for the assays of FLP in pharmaceutical formulations and spiked tap water samples with average recoveries of 87% – 95%. 

scholarly journals Construction of Photoelectrochemical DNA Biosensors Based on TiO2@Carbon Dots@Black Phosphorous Quantum Dots

Micromachines ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1523
Author(s):  
Kai Song ◽  
Jianwei Lin ◽  
Yafeng Zhuang ◽  
Zhizhong Han ◽  
Jinghua Chen
Keyword(s):  
Quantum Dots ◽  
Carbon Dots ◽  
Detection Method ◽  
Black Phosphorus ◽  
Raw Material ◽  
Dna Biosensors ◽  
Detection Range ◽  
Transmission Electron ◽  
Target Dna ◽  
Black Phosphorus Quantum Dots

In this work, carbon dots (CDs) and black phosphorus quantum dots (BPQDs) were used to decorate titanium dioxide to enhance the photoelectrochemical (PEC) properties of the nanocomposites (TiO2@CDs@BPQDs), and the modified nanocomposites were used to sensitively detect DNA. We used the hydrothermal method and citric acid as a raw material to prepare CDs with good dispersion and strong fluorescence properties. BPQDs with a uniform particle size were prepared from black phosphorus crystals. The nanocomposites were characterized by fluorescence spectroscopy, UV-Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The preparation method of the working electrode was explored, the detection conditions were optimized, and the sensitive detection of target DNA was achieved. The results demonstrate that CDs and BPQDs with good optical properties were successfully prepared, and they were successfully combined with TiO2 to improve the PEC performance of TiO2@CDs@BPQDs. The TiO2-based PEC DNA detection method was constructed with a detection limit of 8.39 nM. The constructed detection method has many advantages, including good sensitivity, a wide detection range, and good specificity. This work provides a promising PEC strategy for the detection of other biomolecules.

scholarly journals An Environmental Friendly Procedure for Photometric Determination of Hypochlorite in Tap Water Employing a Miniaturized Multicommuted Flow Analysis Setup

2011 ◽  
Vol 2011 ◽  
pp. 1-6 ◽  
Author(s):  
Sivanildo S. Borges ◽  
Boaventura F. Reis
Keyword(s):  
Tap Water ◽  
Accuracy Assessment ◽  
Flow Analysis ◽  
Photometric Determination ◽  
Waste Generation ◽  
Relative Standard ◽  
Significant Difference ◽  
Leucocrystal Violet ◽  
Reagent Consumption

A photometric procedure for the determination ofClO-in tap water employing a miniaturized multicommuted flow analysis setup and an LED-based photometer is described. The analytical procedure was implemented using leucocrystal violet (LCV; 4,4′,4′′-methylidynetris (N,N-dimethylaniline), C25H31N3) as a chromogenic reagent. Solenoid micropumps employed for solutions propelling were assembled together with the photometer in order to compose a compact unit of small dimensions. After control variables optimization, the system was applied for the determination ofClO-in samples of tap water, and aiming accuracy assessment samples were also analyzed using an independent method. Applying the pairedt-test between results obtained using both methods, no significant difference at the 95% confidence level was observed. Other useful features include low reagent consumption, 2.4 μg of LCV per determination, a linear response ranging from 0.02 up to 2.0 mg L−1  ClO-, a relative standard deviation of 1.0% (n=11) for samples containing 0.2 mg L−1  ClO-, a detection limit of 6.0 μg L−1  ClO-, a sampling throughput of 84 determinations per hour, and a waste generation of 432 μL per determination.

Zinc oxide impregnated resin for preconcentration and spectrophotometric determination of uranyl ions in aqueous solutions

2018 ◽  
Vol 106 (7) ◽  
pp. 569-579
Author(s):  
O. A. Elhefnawy ◽  
A. A. Elabd
Keyword(s):  
Aqueous Solutions ◽  
Spectrophotometric Determination ◽  
Adsorption Process ◽  
Fourier Transforms ◽  
Sol Gel ◽  
Uranyl Ions ◽  
X Ray ◽  
Relative Standard ◽  
Impregnated Resin

Abstract The objective of this work is to find a new, efficient and alternate low-cost adsorbent for preconcentration and spectrophotometric determination of uranyl ions U(VI) from aqueous solution. For this reason the new impregnated resin (ZnO/7HP) has been prepared by sol-gel technique. Characterization of ZnO/7HP was conducted using scanning electron microscopy/energy-dispersive X-ray spectrometer and X-ray diffraction, and Fourier transforms infrared spectroscopy. Several important parameters influencing the U(VI) adsorption such as pH, adsorbent amount, initial U(VI) concentration, contact time and temperature were investigated systematically by batch experiments. The obtained results showed that the equilibrium adsorption data were well fitted to the Langmuir model with a maximum adsorption amount of 24.96 mg/g. While the adsorption kinetics data were described well by the pseudo-second order model. This result indicates that the adsorption process is chemisorption. Thermodynamic results indicate that the U(VI) adsorption process is endothermic nature and favors at high temperature. Hydrochloric acid was used for preconcentration of U(VI) and detected spectrophotometry after the reaction with Arsenazo III. According to the definition of International Union of Pure and Applied Chemistry, the detection limit of this method was 0.12 μg/L. The relative standard deviation under optimum conditions is less than 3.0 % (n=5). The new impregnated resin ZnO/7HP is a promising adsorbent for preconcentration and spectrophotometric determination of U(VI) in aqueous solutions.

A simple and standardized method for the determination of total solanesol in potato leaves and its extracts based on HPLC-MS

2020 ◽  
Author(s):  
Tao Lan ◽  
Congcong Yu ◽  
Ren Li ◽  
Zheng Ma ◽  
Xingjun Xi ◽  
...  
Keyword(s):  
Coenzyme Q10 ◽  
Agricultural Waste ◽  
Vitamin K2 ◽  
Raw Material ◽  
Extraction Solvent ◽  
Three Samples ◽  
Relative Standard ◽  
Stems And Leaves ◽  
Standardized Method

Abstract Background Solanesol is an important pharmaceutical intermediate raw material, mainly used to synthesize coenzyme Q10, vitamin K2. It can be found prominent in potato stems and leaves. But now potato stems and leaves are always abandoned or discarded as they are not suitable for use as feed in aquaculture or other purposes. These agricultural waste resources can be reutilized as the corresponding extracts. Objective To develop a simple and standardized method for the detection of total solanesol in potato leaves and its extracts. Methods N-hexane was chosen as the extraction solvent for three times in the solanesol extraction from potato leaves. HPLC-MS was used for the detection. Results The LOQ was 0.3 µg/g and the linear range was from 0.1 µg/mL to 50 µg/mL. The precision and stability were evaluated by the relative standard deviations (RSDs) of three samples (potato leaves, Extract-1, Extract-2) for interday and intraday. The accuracy of the method was evaluated by the recoveries of three different spiked concentrations of solanesol for three samples, and results showed it ranged from 80.7% to 99.0% with RSDs less than 8.7%. Conclusions The method we established can provide a simple and standardized way for the extraction and detection of total solanesol. Highlights The work laid a foundation for the resource reutilization of potato stem and leaf.

Gas Chromatographic Methods for Doxepin Isomers, Related Compounds, and Organic Volatile Impurities in Raw Materials and Doxepin Isomers in Capsules

1992 ◽  
Vol 75 (5) ◽  
pp. 804-808 ◽  
Author(s):  
Terry D Cyr ◽  
Robert C Lawrence ◽  
Edward G Lovering
Keyword(s):  
Standard Deviation ◽  
Relative Standard Deviation ◽  
Raw Materials ◽  
Raw Material ◽  
Chromatographic Methods ◽  
Relative Standard ◽  
E And Z Isomers ◽  
Related Compounds ◽  
Volatile Impurities

Abstract Gas chromatographic methods have been developed for the determination of doxepin as the sum of the resolved E and Z isomers, 4 doxepin-related compounds, and organic volatile impurities in drug raw material. Minimum quantifiable amounts of the related compounds in raw materials are less than 0.05%. A method for assay of doxepin, as the total of the E and Z isomers, in capsules was also developed; relative standard deviation is less than 1% for the drug assay. Eleven raw material and 18 capsule samples were examined. No drug-related compounds or U.S. Pharmacopeia- or European Pharmacopeia-limited organic volatile impurities were detected in any of the samples.

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