A low-cost and simple paper-based microfluidic device for simultaneous multiplex determination of different types of chemical contaminants in food

2015 ◽  
Vol 68 ◽  
pp. 14-19 ◽  
Author(s):  
Yali Zhang ◽  
Peng Zuo ◽  
Bang-Ce Ye
Processes ◽  
2020 ◽  
Vol 8 (9) ◽  
pp. 1048
Author(s):  
David Díez ◽  
Ana Urueña ◽  
Raúl Piñero ◽  
Aitor Barrio ◽  
Tarja Tamminen

The standard method for determining the biomass composition, in terms of main lignocellulosic fraction (hemicellulose, cellulose and lignin) contents, is by chemical method; however, it is a slow and expensive methodology, which requires complex techniques and the use of multiple chemical reagents. The main objective of this article is to provide a new efficient, low-cost and fast method for the determination of the main lignocellulosic fraction contents of different types of biomasses from agricultural by-products to softwoods and hardwoods. The method is based on applying deconvolution techniques on the derivative thermogravimetric (DTG) pyrolysis curves obtained by thermogravimetric analysis (TGA) through a kinetic approach based on a pseudocomponent kinetic model (PKM). As a result, the new method (TGA-PKM) provides additional information regarding the ease of carrying out their degradation in comparison with other biomasses. The results obtained show a good agreement between experimental data from analytical procedures and the TGA-PKM method (±7%). This indicates that the TGA-PKM method can be used to have a good estimation of the content of the main lignocellulosic fractions without the need to carry out complex extraction and purification chemical treatments. In addition, the good quality of the fit obtained between the model and experimental DTG curves (R2Adj = 0.99) allows to obtain the characteristic kinetic parameters of each fraction.


Talanta ◽  
2017 ◽  
Vol 170 ◽  
pp. 36-40
Author(s):  
Tereza Mašková ◽  
Lenka Hárendarčíková ◽  
Jan Petr

Author(s):  
Mohamad Afiq Mohamed Huri ◽  
Umi Kalthom Ahmad ◽  
Mustafa Omar

Improvised explosive devices  or also known as homemade explosive devices are frequently abused for public terrorism. This types of explosive devices are well fabricated and  made in improvised manner by incorporating military or commercially sourced explosive. It is often used for terrorism as the material of the devices are readily available at low cost and can be obtain legally without any suspicion from the sellers. Chemical composition of explosives holds a lot of useful information in establishing a link between a perpetrator and a bombing case. Analysis of post-blast explosive and pre-blast explosive is equally important since the chemical reaction during explosion will change the product of the composition. Different types of explosive material are also expected to give different composition profiling.  In this study, four types of pyrotechnics explosives packed in pipe bombs were utilized via sampling exercise. Cotton swabbing technique was employed as method extraction as it is easy to perform, rapid, less solvent use and lab time are reduced.The determination of anionic inorganic constituents of improvised explosives were  performed using ion chromatography. Post blast residues were analyzed to compare the changes of inorganic ions to its origin from pre blast samples. Inorganic ions were separated using Metrosep A SUPP 5 column and an eluent consisting of 1.0 mmol/L of NaHCO3 with 3.2 mmol/L Na2CO3. Anions of interest including  NO2-, NO32-, PO42-, SO42-, SCN-,  and ClO4-  have been successfully separated within 60 minutes. Types and amount of anion detected are different from different materials of explosive devices.________________________________________GRAPHICAL ABSTRACT


2019 ◽  
Vol 16 (2) ◽  
pp. 279-287
Author(s):  
Azmi Naqvi ◽  
Dinesh C. Sharma ◽  
Pradip Nahar

Herein, gravitational force based low cost colorimetric microfluidic device is developed for diagnostic purpose. Microfluidic system is developed by using discarded pen refills. Refill is filled with three layers of polymer. Bottom of the refill is filled with the polymer polyvinyl chloride (PVC). Second layer from the bottom i.e the layer above PVC layer is filled with silica gel immobilized with horse radish peroxidase (HRP), glucose oxidase (GOD) and o- dianisidine (dye). Whereas, third and the top most layer is filled with untreated silica gel. One drop of blood is poured at the inlet of microfluidic device. Without applying any external power, blood moves through the silica packed region by gravitational pull and capillary action of silica gel. Serum separation started within 30 seconds and subsequently within 2 min., serum successfully separates from blood by pure silica gel. The separated serum then comes in contact with the silica gel immobilized with enzymes and dye. The colour of the silica beads immobilized with enzymes and dye changes from white to orange when comes in contact with glucose in serum. Determination of the glucose in the blood is carried out on a desktop scanner. The developed microfluidic device do not require (i) pump or device to propel the fluid (ii) any type of special mesh or sieve to separate the serum from the blood. Microfluidic device developed is cheap and suitable for low cost setting areas.


Lab on a Chip ◽  
2016 ◽  
Vol 16 (2) ◽  
pp. 345-352 ◽  
Author(s):  
Deonir Agustini ◽  
Márcio F. Bergamini ◽  
Luiz Humberto Marcolino-Junior

A microfluidic thread-based electroanalytical device (μTED) was constructed with extremely low cost materials and a manufacturing process free of equipment, for simultaneous determination of electroactive species by multiple pulse amperometry.


2020 ◽  
Vol 70 (12) ◽  
pp. 4594-4600

The purpose of this study was to characterize some types of biomass wastes resulted from different activities such as: agriculture, forestry and food industry using thermogravimetric and ICP-MS analyses. Also, it was optimized an ICP-MS method for the determination of As, Cd and Pb from biomass ash samples. The ICP-MS analysis revealed that the highest concentration of metals (As, Cd, Pb) was recorded in the wood waste ash sample, also the thermogravimetric analysis indicated that the highest amount of ash was obtained for the same sample (26.82%). The biomass wastes mentioned in this study are alternative recyclable materials, reusable as pellets and briquettes. Keywords: ash, biomass, ICP-MS, minor elements, TG


2018 ◽  
Vol 69 (5) ◽  
pp. 1139-1144
Author(s):  
Iosif Lingvay ◽  
Adriana Mariana Bors ◽  
Livia Carmen Ungureanu ◽  
Valerica Stanoi ◽  
Traian Rus

For the purpose of using three different types of painting materials for the inner protection of the transformer vats, their behavior was studied under actual conditions of operation in the transformer (thermal stress in electro-insulating fluid based on the natural ester in contact with copper for electro-technical use and electro-insulating paper). By comparing determination of the content in furans products (HPLC technique) and gases formed (by gas-chromatography) in the electro-insulating fluid (natural ester with high oleic content) thermally aged at 130 �C to 1000 hours in closed glass vessels, it have been found that the presence the investigated painting materials lead to a change in the mechanism and kinetics of the thermo-oxidation processes. These changes are supported by oxygen dissolved in oil, what leads to decrease both to gases formation CO2, CO, H2, CH4, C2H4 and C2H6) and furans products (5-HMF, 2-FOL, 2 -FAL and 2-ACF). The painting materials investigated during the heat treatment applied did not suffer any remarkable structural changes affecting their functionality in the electro-insulating fluid based on vegetable esters.


2020 ◽  
Vol 16 (8) ◽  
pp. 1032-1040
Author(s):  
Laleh Samini ◽  
Maryam Khoubnasabjafari ◽  
Mohamad M. Alimorad ◽  
Vahid Jouyban-Gharamaleki ◽  
Hak-Kim Chan ◽  
...  

Background: Analysis of drug concentrations in biological fluids is required in clinical sciences for various purposes. Among other biological samples, exhaled breath condensate (EBC) is a potential sample for follow up of drug concentrations. Methods: A dispersive liquid-liquid microextraction (DLLME) procedure followed by a validated liquid chromatography method was employed for the determination of budesonide (BDS) in EBC samples collected using a homemade setup. EBC is a non-invasive biological sample with possible applications for monitoring drug concentrations. The proposed analytical method is validated according to the FDA guidelines using EBC-spiked samples. Its applicability is tested on EBC samples collected from healthy volunteers receiving a single puff of BDS. Results: The best DLLME conditions involved the use of methanol (1 mL) as a disperser solvent, chloroform (200 μL) as an extraction solvent, and centrifugation rate of 3500 rpm for 5 minutes. The method was validated over a concentration range of 21-210 μg·L-1 in EBC. Inter- and intra-day precisions were less than 10% where the acceptable levels are less than 20%. The validated method was successfully applied for the determination of BDS in EBC samples. Conclusion: The findings of this study indicate that the developed method can be used for the extraction and quantification of BDS in EBC samples using a low cost method.


2020 ◽  
Vol 16 (4) ◽  
pp. 456-464
Author(s):  
Danilo F. Rodrigues ◽  
Hérida R.N. Salgado

Background: A simple, eco-friendly and low-cost Infrared (IR) method was developed and validated for the analysis of Cefepime Hydrochloride (CEF) in injectable formulation. Different from some other methods, which employ organic solvents in the analyses, this technique does not use these types of solvents, removing large impacts on the environment and risks to operators. Objective: This study aimed at developing and validating a green analytical method using IR spectroscopy for the determination of CEF in pharmaceutical preparations. Methods: The method was validated according to ICH guidelines and the quantification of CEF was performed in the spectral region absorbed at 1815-1745 cm-1 (stretching of the carbonyl group of β- lactam ring). Results: The validated method showed to be linear (r = 0.9999) in the range of 0.2 to 0.6 mg/pellet of potassium bromide, as well as for the parameters of selectivity, precision, accuracy, robustness and Limits of Detection (LOD) and Quantification (LOQ), being able to quantify the CEF in pharmaceutical preparations. The CEF content obtained by the IR method was 103.86%. Conclusion: Thus, the method developed may be an alternative in the quality control of CEF sample in lyophilized powder for injectable solution, as it presented important characteristics in the determination of the pharmaceutical products, with low analysis time and a decrease in the generation of toxic wastes to the environment.


2019 ◽  
Vol 15 (6) ◽  
pp. 628-634
Author(s):  
Rong Liu ◽  
Jie Li ◽  
Tongsheng Zhong ◽  
Liping Long

Background: The unnatural levels of dopamine (DA) result in serious neurological disorders such as Parkinson’s disease. Electrochemical methods which have the obvious advantages of simple operation and low-cost instrumentation were widely used for determination of DA. In order to improve the measurement performance of the electrochemical sensor, molecular imprinting technique and graphene have always been employed to increase the selectivity and sensitivity. Methods: An electrochemical sensor which has specific selectivity to (DA) was proposed based on the combination of a molecular imprinting polymer (MIP) with a graphene (GR) modified gold electrode. The performance and effect of MIP film were investigated by differential pulse voltammetry (DPV) and cyclic voltammetry (CV) in the solution of 5.0 ×10-3 mol/L K3[Fe(CN)6] and K4[Fe(CN)6] with 0.2 mol/L KCl at room temperature. Results: This fabricated sensor has well repeatability and stability, and was used to determine the dopamine of urine. Under the optimized experiment conditions, the current response of the imprinted sensor was linear to the concentration of dopamine in the range of 1.0×10-7 ~ 1.0×10-5 mol/L, the linear equation was I (µA) = 7.9824+2.7210lgc (mol/L) with the detection limit of 3.3×10-8 mol/L. Conclusion: In this work, a highly efficient sensor for determination of DA was prepared with good sensitivity by GR and great selectivity of high special recognization ability by molecular imprinting membrane. This proposed sensor was used to determine the dopamine in human urine successfully.


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