scholarly journals Determination of Pyrethroids in Tea Brew by GC-MS Combined with SPME with Multiwalled Carbon Nanotube Coated Fiber

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Dongxia Ren ◽  
Chengjun Sun ◽  
Guanqun Ma ◽  
Danni Yang ◽  
Chen Zhou ◽  
...  
Keyword(s):  
Solid Phase ◽  
Steel Wire ◽  
Correlation Coefficients ◽  
Organic Reagent ◽  
Gas Chromatography Mass Spectrometry ◽  
Multiwalled Carbon ◽  
Coated Fiber ◽  
Relative Standard ◽  
Reagent Consumption ◽  
Optimized Conditions

A new method has been developed to simultaneously determine 7 pyrethroid residues in tea brew using gas chromatography-mass spectrometry (GC-MS) combined with solid phase microextraction (SPME) with multiwalled carbon nanotubes (MWCNTs) coated fiber. The MWCNTs coated fiber of SPME was homemade by using stainless steel wire as coating carrier and polyacrylonitrile (PAN) solution as adhesive glue. Under the optimized conditions, a good linearity was shown for bifenthrin, fenpropathrin, permethrin, and cyfluthrin in 1–50 ng mL−1 and for cypermethrin, fenvalerate, and deltamethrin in 5–50 ng mL−1. The correlation coefficients were in the range of 0.9948–0.9999. The average recoveries of 7 pyrethroids were 94.2%–107.3% and the relative standard deviations (RSDs) were less than 15%. The detection limit of the method ranged from 0.12 to 1.65 ng mL−1. The tea brew samples made from some commercial tea samples were analyzed. Among them, bifenthrin, fenpropathrin, and permethrin were found. The results show that the method is rapid and sensitive and requires low organic reagent consumption, which can be well used for the detection of the pyrethroids in tea brew.

scholarly journals Ionic Liquid-modified NiTi Composite Nanosheets Coating for Efficient Solid Phase Microextraction of Octadecylamine in Brine

2019 ◽  
pp. 1-8
Author(s):  
Huiju Wang
Keyword(s):  
Ionic Liquid ◽  
Solid Phase Microextraction ◽  
Extraction Efficiency ◽  
Solid Phase ◽  
Correlation Coefficients ◽  
Fiber Coating ◽  
Relative Standard ◽  
Optimized Conditions ◽  
As Solid Phase

Ionic     liquid (IL), 1-dodecyl-3-methylimidazolium-3-hydroxy-2-naphthoate (C12mimHNC) was synthesized and coated on the surface of NiTi as solid phase microextractiom fiber coating for determination the octadecylamine in brine. Prior to modification with IL, the NiTi was hydrothermally treated for in-situ growth of titanium and nickel oxide composite nanosheets (TiO2/NiOCNSs). The TiO2/NiOCNSs fibers coating was oriented  around the NiTi  substrate and  presented  double-faced  open  access  sites,  which provided a desired support framework for the further modification with IL. The extraction performance of C12mimHNC-TiO2/NiOCNSs fiber coating was evaluated for       detection of octadecylamine (ODA) coupled to HPLC with UV detection. As a result, the C12mimHNC-TiO2/NiOCNSs fiber coating illustrated excellent adsorption and extraction capability for ODA. The main factors affected extraction efficiency were optimized. Under the optimized  conditions,  good  linearity was  obtained  in  the  range of  1-150  µg/L with correlation  coefficients  (r2)  above  0.985.  Limits of detection (LODs) for  the  developed method was 0.280 µg/L. The proposed method was first applied to extract the ODA in brine samples. Relative recoveries varied from 78.3% to 96.5% at spiking level of 15µg/L and 30 µg/L with the relative standard deviations (RSDs) less than 8.7%.

scholarly journals Solid phase microextraction of organochlorine pesticides in water using MWCNTs-doped polypyrrole coated on steel fiber

2020 ◽  
Vol 3 (04) ◽  
pp. 40-51
Author(s):  
Hamideh Asadollahzadeh ◽  
Ebrahim Noroozian
Keyword(s):  
Organochlorine Pesticides ◽  
Water Samples ◽  
Solid Phase ◽  
Semivolatile Organic Compounds ◽  
Extraction Temperature ◽  
Multiwalled Carbon ◽  
Relative Standard ◽  
Pesticides In Water ◽  
Polypyrrole Composite ◽  
Optimized Conditions

The analysis of organochlorine pesticides (OCPs) residues has received an increasing attention in the last decades. Solid-phase microextration (SPME) is a convenient and fast analytical method, which has been widely used for the determination of volatile and semivolatile organic compounds in aqueous samples. The multiwalled carbon nanotubes/polypyrrole composite coating was used for the SPME of OCPs in water samples. The effects of various parameters on the efficiency of SPME process such as extraction time, extraction temperature, ionic strength, desorption time, and desorption temperature were studied. Under optimized conditions, the detection limits for the OCPs varied between 0.051 and 0.39 pg mL-1, the inter-day and intra-day relative standard deviations for various OCPs using a single fiber were 6.5-11.5% and 3.6-11.5, respectively. The linear ranges varied between 0.001 and 1 ng mL-1. The method was successfully applied to the analysis of ground water samples with the recoveries from 86 to 110%.

scholarly journals Development of electrodeposited nanostructural poly (o-aminophenol) coating as a solid phase microextraction fiber for determination of bisphenol A

2021 ◽  
Vol 4 (02) ◽  
pp. 34-46
Author(s):  
Mohammad Saraji ◽  
Bahman Farajmand ◽  
Esmaeil Heydari Bafrouei
Keyword(s):  
Acetic Anhydride ◽  
Bisphenol A ◽  
Solid Phase Microextraction ◽  
Limit Of Detection ◽  
Solid Phase ◽  
Steel Wire ◽  
Flame Ionization ◽  
Baby Bottle ◽  
Relative Standard ◽  
Optimized Conditions

In this research nanostructural poly (o-aminophenol) was synthesized by electropolymerization and used for solid phase microextraction procedure (SPME). Thin film of Poly (o-aminophenol) (4 µm thickness) was shaped by sweep potential for 45 min on the surface of stainless steel wire. Polymer was synthesized by potentiostat procedure too. Prepared polymer by sweep potential procedure showed nanostructures on the surface. Acetic anhydride was employed for derivatization of bisphenol A (BPh-A) and analysis of acetylated BPh-A was utilized by gas chromatography-flame ionization detector (GC-FID). Affecting parameters on derivatization and extraction such as amount of acetic anhydride, stirring rate, temperature, ionic strength and extraction time were optimized. The limit of detection (LOD) and relative standard divisions (RSDs%) were achieved 0.6 µgL-1 and less than 6.8%, respectively under optimized conditions. Finally proposed method was used for extraction of bisphenol A from leaching of baby and drinking water bottles. Relative recovery was achieved 98% for leaching from drinking bottle. In leaching from plastic baby bottle, bisphenol A (BPh-A) was detected in the range 5–15 µg L-1.  

Green Dispersive Micro Solid-Phase Extraction using Multiwalled Carbon Nanotubes for Preconcentration and Determination of Cadmium and Lead in Food, Water, and Tobacco Samples

2020 ◽  
Vol 16 (4) ◽  
pp. 381-392
Author(s):  
Ayman A. Gouda ◽  
Ali H. Amin ◽  
Ibrahim S. Ali ◽  
Zakia Al Malah
Keyword(s):  
Carbon Nanotubes ◽  
Solid Phase Extraction ◽  
Multiwalled Carbon Nanotubes ◽  
Solid Phase ◽  
Certified Reference Materials ◽  
Phase Extraction ◽  
Multiwalled Carbon ◽  
Flame Atomic Absorption ◽  
Relative Standard ◽  
Separation And Preconcentration

Background: Cadmium (Cd2+) and lead (Pb2+) have acute and chronic effects on humans and other living organisms. In the present work, new, green and accurate dispersive micro solid-phase extraction (DμSPE) method for the separation and preconcentration of trace amounts of cadmium (Cd2+) and lead (Pb2+) ions in various food, water and tobacco samples collected from Saudi Arabia prior to its Flame Atomic Absorption Spectrometric (FAAS) determinations was developed. Methods: The proposed method was based on a combination of oxidized multiwalled carbon nanotubes (O-MWCNTs) with a new chelating agent 5-benzyl-4-[4-methoxybenzylideneamino)-4H- 1,2,4-triazole-3-thiol (BMBATT) to enrich and separate trace levels of Cd2+ and Pb2+. The effect of separation parameters was investigated. The validation of the proposed preconcentration procedure was performed using certified reference materials. Results: Analyte recovery values ranged from 95-102%, indicating that the method is highly accurate. Furthermore, precision was demonstrated by the relative standard deviation (RSD < 3.0%). The limits of detection were 0.08 and 0.1 μg L−1 for Cd2+ and Pb2+ ions, respectively. The preconcentration factor was 200. Conclusion: The proposed method was used for the estimation of Cd2+ and Pb2+ ion content in various real samples, and satisfactory results were obtained. The proposed method has high adsorption capacity, rapid adsorption equilibrium, extremely low LODs, high preconcentration factors and shortens the time of sample preparation in comparison to classical SPE.

scholarly journals Adsorption Efficiency of Pentafl Uorobenzene on Ionic Liquids-Based Silicas

2018 ◽  
Vol 20 (3) ◽  
pp. 47-52 ◽  
Author(s):  
Xiaofei Wang ◽  
Liangwen Lin ◽  
Jinfeng Xie ◽  
Xuemin Yan ◽  
Wei Xiao ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Solid Phase ◽  
Solution System ◽  
Ph Values ◽  
Several Variables ◽  
Effi Ciency ◽  
Relative Standard ◽  
Effects Of Ph ◽  
Chloride Salts ◽  
Optimized Conditions

Abstract The adsorption of pentafl uorobenzene on nine ionic liquid-based silicas was investigated using solid phase extraction. The effects of several variables such as the type of ionic liquid groups, adsorption time, temperatures and water ratio in the solution system were experimentally evaluated. The imidazole-chloride ionic liquid group based silica exhibited the highest adsorption effi ciency under the optimized conditions of 5 min adsorption at 30oC in water/methanol (30:70, vol%) solution. In addition, the effects of pH, as well as type and concentrations of chloride salts were investigated. At pH values other than neutral and high salt concentration, the adsorption effi ciency was reduced. Finally, the relative standard deviation of less than 5.8% over a 5-day period showed a high precision for the nine tested sorbents.

scholarly journals Determination of multi-class herbicides in soil by liquid-solid extraction coupled with headspace solid phase microextraction method

2016 ◽  
Vol 81 (8) ◽  
pp. 923-934 ◽  
Author(s):  
Rada Djurovic-Pejcev ◽  
Tijana Djordjevic ◽  
Vojislava Bursic
Keyword(s):  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Soil Samples ◽  
Gas Chromatography Mass Spectrometry ◽  
Optimum Number ◽  
Polydimethyl Siloxane ◽  
Headspace Solid Phase Microextraction ◽  
Relative Standard ◽  
Detection And Quantification

A method is described for simultaneous determination of five herbicides (metribuzin, acetochlor, clomazone, oxyfluorfen and dimethenamid) belonging to different pesticides groups in soil samples. Developed headspace solid phase microextraction method (HS-SPME) in combination with liquid-solid sample preparation (LS) was optimized and applied in the analysis of some agricultural samples. Optimization of microextraction conditions, such as temperature, extraction time and sodium chloride (NaCl) content was perfor-med using 100 ?m polydimethyl-siloxane (PDMS) fiber. The extraction effi-ciencies of methanol, methanol:acetone=1:1 and methanol:acetone:hexane= =2:2:1 and the optimum number of extraction steps during the sample prepa-ration, were tested, as well. Gas chromatography-mass spectrometry (GC-MS) was used for detection and quantification, obtaining relative standard deviation (RSD) below 13%, and recovery values higher than 83% for multiple analyses of soil samples fortified at 30 ?g kg-1 of each herbicide. Limits of detection (LOD) were less than 1.2 ?g kg-1 for all the studied herbicides.

The Determination of Eight Pesticides in Panax notoginseng of Chinese Traditional Medicine Using Solid-Phase Extraction and Gas Chromatography-Mass Spectrometry

2012 ◽  
Vol 485 ◽  
pp. 68-71
Author(s):  
Na Wu ◽  
Yu Da Zhang ◽  
Wei Liu ◽  
Ping Yi ◽  
Ze Feng Wang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Solid Phase Extraction ◽  
Solid Phase ◽  
Panax Notoginseng ◽  
Gas Chromatography Mass Spectrometry ◽  
Phase Extraction ◽  
Selected Ion Monitoring ◽  
Chromatography Mass Spectrometry ◽  
Relative Standard

A simple and effective extraction method based on solid-phase extraction (SPE) was developed to determine chlorothalonil, metalaxyl, triadimefon, dimetachlone, procymidone, flumetralin, oxadixyl and iprodione in Panax Notoginseng using gas chromatography-mass spectrometry with selected ion monitoring (GC/MS, SIM). The prepared samples were analysed with GC-MS in the selected ion monitoring mode (SIM) using one target and two or three qualitative ions for each analyte. In the method, hexane - dichloromethane（6:4，v/v）was selected to effectively extract the pesticides from the Panax Notoginseng samples. Solid-phase extraction was carried out using Supelclean ENVI-Carb/NH2 SPE Column with acetonitrile-toluene (3:1, v/v) as the eluted solvent. In the linear range of each pesticide, the correlation coefficient was R2≥0.99. The limit of detection ranged from 0.001 to 0.05 µg.mL-1, average recoveries ranged from 79.80% to 95.00%, with relative standard deviations between 1.96% and 4.32% for all 8 pesticides.They were readily achieved with this method for all tested pesticides.

scholarly journals Preconcentration of Bismuth(III) and Copper(II) by Solid-Phase Extraction and Subsequent Determination by Differential Pulse Polarography

2001 ◽  
Vol 84 (1) ◽  
pp. 47-52 ◽  
Author(s):  
Anju Bhalotra ◽  
Bal Krishan Prui
Keyword(s):  
Solid Phase ◽  
Supporting Electrolyte ◽  
Saturated Calomel Electrode ◽  
Correlation Coefficients ◽  
Differential Pulse ◽  
Differential Pulse Polarography ◽  
Pulse Polarography ◽  
Relative Standard ◽  
Microcrystalline Naphthalene

Abstract A differential pulse polarographic method is proposed for the trace determination of bismuth and copper from large volumes of aqueous samples after adsorption of their 1-(2-thiazolylazo)-2-naphthol complexes onto microcrystalline naphthalene in the pH ranges of 7.2–9.0 and 4.0–7.8, respectively. Bismuth and copper are desorbed from microcrystalline naphthalene with 9 mL 1M HCl. Well-defined peaks are obtained at Ep = −0.09 and −0.20 V versus a saturated calomel electrode, in an HCl–isoquinoline medium as the supporting electrolyte, for bismuth and copper, respectively. Bismuth is reduced reversibly with a 3-electron change, whereas copper is reduced irreversibly under these conditions. The detection limits are 55 ng/mL for bismuth and 91 ng/mL for copper. Linearity is maintained in the concentration ranges of 0.18–13.5 and 0.30-17.3 μg/mL for bismuth and copper, respectively, with corresponding correlation coefficients of 0.9996 and 0.9885. The relative standard deviations are 1.0% for bismuth at 2.0 μg/mL and 1.4% for copper at 5.0 μg/mL. Various parameters were optimized to develop conditions for the determination of these metal ions in various samples.

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