scholarly journals Electrochemical Sensor for Methamphetamine Detection Using Laser-Induced Porous Graphene Electrode

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 73
Author(s):  
Kasrin Saisahas ◽  
Asamee Soleh ◽  
Sunita Somsiri ◽  
Patthamaporn Senglan ◽  
Kiattisak Promsuwan ◽  
...  
Keyword(s):  
Electrochemical Sensor ◽  
Biological Fluids ◽  
Cost Effective ◽  
Good Precision ◽  
Step Method ◽  
Pattern Design ◽  
Porous Graphene ◽  
Stencil Mask ◽  
Relative Standard ◽  
One Step

A 3D porous graphene structure was directly induced by CO2 laser from the surface of Kapton tape (carbon source) supported by polyethylene terephthalate (PET) laminating film. A highly flexible laser-induced porous graphene (LI-PGr) electrode was then fabricated via a facile one-step method without reagent and solvent in a procedure that required no stencil mask. The method makes pattern design easy, and production cost-effective and scalable. We investigated the performance of the LI-PGr electrode for the detection of methamphetamine (MA) on household surfaces and in biological fluids. The material properties and morphology of LI-PGr were analysed by scanning electron microscopy (SEM), energy dispersive x-ray (EDX) and Raman spectroscopy. The LI-PGr electrode was used as the detector in a portable electrochemical sensor, which exhibited a linear range from 1.00 to 30.0 µg mL−1 and a detection limit of 0.31 µg mL−1. Reproducibility was good (relative standard deviation of 2.50% at 10.0 µg mL−1; n = 10) and anti-interference was excellent. The sensor showed good precision and successfully determined MA on household surfaces and in saliva samples.

Development of a Novel Method for Rapid Discrimination between Wild and Farmed Sea Bream

2019 ◽  
Vol 82 (11) ◽  
pp. 1870-1873
Author(s):  
SIMONA SCIUTO ◽  
GIOVANNA ESPOSITO ◽  
CHIARA GUGLIELMETTI ◽  
MARIA MAZZA ◽  
CINZIA COCCO ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Cost Effective ◽  
Sea Bream ◽  
Good Precision ◽  
Simple Method ◽  
Commercial Fish ◽  
Acid Ratio ◽  
Relative Standard ◽  
Student’S T ◽  
Rapid Discrimination

ABSTRACT A simple method based on direct sampling analysis, coupled with a time of flight mass spectrometer, was developed to discriminate between wild and farmed sea bream on the basis of the docosahexaenoic and arachidonic fatty acid ratio. Good precision in repeatability and reproducibility (relative standard deviation < 15%) was obtained. The fatty acid ratios of the two types of fish were statistically significant (Student's t < 0.001). The use of a simple, rapid, and cost-effective tool could aid in the detection of commercial fish fraud, increase the number of controlled samples, and strengthen control along the entire commercial chain.

A novel ascorbic acid electrochemical sensor based on spherical MOF-5 arrayed on a three-dimensional porous carbon electrode

2016 ◽  
Vol 8 (10) ◽  
pp. 2290-2296 ◽  
Author(s):  
Yonggui Song ◽  
Couchong Gong ◽  
Dan Su ◽  
Yuan Shen ◽  
Yonghai Song ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Electrochemical Sensor ◽  
Porous Carbon ◽  
Three Dimensional ◽  
Carbon Composites ◽  
Carbon Electrode ◽  
Step Method ◽  
One Step ◽  
Porous Carbon Electrode

The MOF-5 microstructures supported by three-dimensional kenaf stem-derived porous carbon composites were constructedviausing a simple one-step method for ascorbic acid sensing.

On the albumin dependence of measurements of free thyroxin. I. Technical performance of seven methods.

1986 ◽  
Vol 32 (1) ◽  
pp. 108-115 ◽  
Author(s):  
G Csako ◽  
M H Zweig ◽  
C Benson ◽  
M Ruddel
Keyword(s):  
Equilibrium Dialysis ◽  
Inverse Correlation ◽  
Albumin Concentration ◽  
Good Precision ◽  
Step Method ◽  
Significant Inverse Correlation ◽  
Technical Performance ◽  
One Step ◽  
The One ◽  
Marked Dependence

Abstract We evaluated three one-step (analog) and two two-step radioimmunoassay for free thyroxin (FT4), and a FT4 index calculated from the total T4 (TT4) and thyroxin-binding globulin (TBG) ratio for technical performance, for correlation with the reference FT4 method (equilibrium dialysis), and for dependence on TBG and albumin concentrations. The one-step methods (Amerlex, Coat-A-Count, and GammaCoat) showed greater precision than the two-step procedures (GammaCoat and Spiria). Results by the latter two techniques, however, correlated better with those by equilibrium dialysis than did those by the analog methods or by TT4/TBG. Only the GammaCoat two-step method had a slight but statistically significant (inverse) correlation with TBG concentration. All three analog methods and TT4/TBG showed a marked dependence on albumin concentration, whereas the Spiria technique showed only a slight dependence. Only equilibrium dialysis was independent of both the TBG and albumin concentration. Thus, despite their good precision, the analog (one-step) FT4 methods and the TT4/TBG approach cannot be expected to produce valid results when the concentration of albumin in serum is abnormally low or high.

One-Step Rapid Synthesis of Al-Based Ag Dendrites for Highly Active and Cost Effective SERS Plasmonic Substrates

2020 ◽  
Vol 861 ◽  
pp. 309-314
Author(s):  
Jian Huang ◽  
Zhe Lei ◽  
Qian Zhang ◽  
Mei Juan Su ◽  
Liang Liu
Keyword(s):  
Organic Contaminants ◽  
Dendritic Structure ◽  
Cost Effective ◽  
Synthesis Process ◽  
Label Free ◽  
Organic Additives ◽  
Sers Substrates ◽  
Highly Active ◽  
Relative Standard ◽  
One Step

Highly active Al-based Ag dendrites SERS plasmonic substrates have been rapidly synthesized by the one-step galvanic displacement reaction without the use of any surfactants and templates. The as-prepared SERS substrates were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. XRD measurements confirmed the metallic nature of the formed Ag dendrites. None of the organic additives were used in the synthesis process, which ensures the substrates surfaces are completely clean and avoiding the introduction of organic contaminants. The innovative rough bionic substrates yield a final silver dendritic structure that offers large specific surface area and high-density hotspots. Using malachite green as a model target, the Al-based Ag dendrites SERS substrates exhibited acceptable reproducibility (relative standard deviation of 23.8%) and high enhancement capacities (pushed the detection limit down to 10 pM). Importantly, these Ag dendrites could potentially be employed as highly active and cost effective flexible SERS sensors for label-free ultrasensitive detection of biomolecules.

scholarly journals Simple UV Spectrophotometric Method for the Determination of Fluvastatin Sodium in Bulk and Pharmaceutical Formulations

2009 ◽  
Vol 6 (4) ◽  
pp. 1233-1239 ◽  
Author(s):  
J. Saminathan ◽  
A. S. Sankar ◽  
K. Anandakumar ◽  
T. Vetrichelvan
Keyword(s):  
Spectrophotometric Method ◽  
Limit Of Detection ◽  
Regression Line ◽  
Cost Effective ◽  
Pharmaceutical Formulations ◽  
Molar Absorptivity ◽  
Good Precision ◽  
Limit Of Quantification ◽  
Relative Standard

A simple and cost effective spectrophotometric method is described for the determination of fluvastatin sodium in pure form and in pharmaceutical formulations. When the drug reacts with sodium hydroxide shows absorption maximum at 304 nm and obeys beer's law in the concentration range 5-25 µg mL-1. The absorbance was found to increase linearly with increasing concentration of FVS, which is corroborated by the calculated correlation coefficient value of 0.9999 (n=5). The apparent molar absorptivity and sandell sensitivity were 1.1905×104and 0.0368844 µg cm-2cm respectively. The slope and intercept of the equation of the regression line are 0.027112 and 0.003539 respectively. The limit of detection and limit of quantification was found to be 0.0811 µg mL-1& 0.2460 µg mL-1. The validity of the described procedure was assessed. Statistical analysis of the result has been carried out revealing high accuracy and good precision. The proposed method was successfully applied to the determination of FVS in pharmaceutical formulations without any interference from common excipients. The relative standard deviations were ≤ 0.937%, with recoveries of 98.60% -101.70%.

Purification of Urokinase from Complex Mixtures Using Immobilized Monoclonal Antibody Against Urokinase Light Chain

1983 ◽  
Vol 49 (01) ◽  
pp. 024-027 ◽  
Author(s):  
David Vetterlein ◽  
Gary J Calton
Keyword(s):  
Monoclonal Antibody ◽  
Light Chain ◽  
Culture Media ◽  
Biological Fluids ◽  
Single Step ◽  
High Yield ◽  
Step Method ◽  
Commercial Preparation ◽  
E Coli ◽  
Tissue Culture Media

SummaryThe preparation of a monoclonal antibody (MAB) against high molecular weight (HMW) urokinase light chain (20,000 Mr) is described. This MAB was immobilized and the resulting immunosorbent was used to isolate urokinase starting with an impure commercial preparation, fresh urine, spent tissue culture media, or E. coli broth without preliminary dialysis or concentration steps. Monospecific antibodies appear to provide a rapid single step method of purifying urokinase, in high yield, from a variety of biological fluids.

Validation of A Simple HPLC-UV Method For the Quantification of Andrographolide in Self-Nano Emulsifying Drug Delivery System (Snedds) For Dissolution Study

2017 ◽  
Vol 7 (04) ◽  
Author(s):  
Syukri Y ◽  
Afetma D. W. ◽  
Sirin M. ◽  
Fajri R. ◽  
Ningrum A. D. K. ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Delivery System ◽  
Delivery System ◽  
Gastric Fluid ◽  
Hplc Method ◽  
Good Precision ◽  
Intestinal Fluid ◽  
Dissolution Medium ◽  
Relative Standard ◽  
Sufficient Precision

This research aim to validation of a simple, rapid and accurate HPLC-UV method for the quantification of andrographolide isolated from Andrographis paniculata Ness in Self Nano Emulsifying Drug Delivery System (SNEDDS) formulation during the dissolution test. The assay was performed using a XTerra® MS C18 column (150 mm X 4.6 mm, five μm) with a mobile phase of methanol and water (70: 30), at 0.8 mL/min flow rate and UV detection of 229 nm. Simulation gastric fluid (SGF) and intestinal fluid (SIF) were prepared as dissolution medium. The validation parameter was conducted including the test on linearity, precision, accuracy, LOD, and LOQ. The result showed an excellent linearity with r = 0.999 and good selectivity for both medium dissolution. The method showed sufficient precision, with a relative standard deviation (RSD) smaller than % Horwitz. The accuracy reported as % recovery was found to be 102.61 and 101.17 % in each SGF and SIF dissolution medium. LOD and LOQ were found 0.46 and 1.40 in SGF medium, 0.87 and 2.64 in SIF medium. In conclusion, the HPLC method developed showed specificity and selectivity with linearity in the working range, good precision and accuracy and suitable for quantification andrographolide in SNEDDS formulation.

Calorimetric Sensor for Ethanol Using Ni2+-nitrilotriacetic Acid (NTA) Resin Immobilized Alcohol Dehydrogenase (ADH)

2020 ◽  
Vol 16 (6) ◽  
pp. 795-799
Author(s):  
YongJin Li
Keyword(s):  
Cost Effective ◽  
Nitrilotriacetic Acid ◽  
Repeated Measurements ◽  
Great Promise ◽  
Calorimetric Sensor ◽  
Controlled Pore Glass ◽  
Pore Glass ◽  
One Step ◽  
Immobilization Matrix ◽  
Enzyme Thermistor

Background: A simple, fast and economic analytical method for the determination of ethanol is important for clinical, biological, forensic and physico-legal purposes. Methods: Ni2+-NTA resin was used as an immobilization matrix for the simple one-step purification/ immobilization of his6-tagged ADH. Different alcohols with a concentration range of 0.5-50% V/V, namely methanol, ethanol and propanol were measured using prepared ADH enzyme thermistor. The ethanol content of Tsingtao beer was tested as a real sample containing alcohol. Reproducibility and stability of prepared ADH enzyme thermistor were also investigated by repeated measurements. Results: In comparison to the controlled pore glass (a common used support for the immobilization of enzyme) used in thermal biosensor, the use of Ni2+-NTA resin not only led to simple one-step purification/ immobilization by his6-tagged ADH binding to Ni2+-NTA resin, but also made the immobilizing supports reusable. The prepared biosensor can be used to determine ethanol and methanol by the calorimetric measurement. A linear range of 1 -32% (V/V) and 2-20% (V/V) was observed for ethanol and methanol, respectively. The detection limits were 0.3% (V/V) and 1% (V/V) for ethanol and methanol, respectively. The tested ethanol concentration of Tsingtao beer was 4.5% V/V, which is comparable with the labeled alcohol by volume (ABV) 4.80%. Conclusion: Ni2+-NTA resin, as an immobilization matrix in ET sensor, provides a simple one-step purification/immobilization for His6-tagged recombinase and a reusable immobilization matrix. The prepared biosensor exhibits good repeatability and stability. Such a new biosensor shows great promise for rapid, simple, and cost-effective analysis of ethanol and methanol, both in qualitative and in quantitative tests.

Determination of Epsilon Aminocaproic Acid Based on Charge Transfer Complexation with p-Nitrophenlol by Spectrophotometry

2020 ◽  
Vol 16 ◽  
Author(s):  
Sheng-Yun Li ◽  
Fang Tian
Keyword(s):  
Charge Transfer ◽  
Aminocaproic Acid ◽  
Concentration Limit ◽  
Official Method ◽  
Good Precision ◽  
Pharmaceutical Dosage Forms ◽  
Relative Standard ◽  
A Charge ◽  
Epsilon Aminocaproic Acid

: A spectrophotometry was investigated for the determination of epsilon aminocaproic acid (EACA) with p-nitrophenol (PNP). The method was based on a charge transfer (CT) complexation of this drug as n-electron donor with π-acceptor PNP. Experiment indicated that the CT complexation was carried out at room temperature for 10 minutes in dimethyl sulfoxide solvent. The spectrum obtained for EACA/PNP system showed the maximum absorption band at wavelength of 425 nm. The stoichiometry of the CT complex was found to be 1:1 ratio by Job’s method between the donor and the acceptor. Different variables affecting the complexation were carefully studied and optimized. At the optimum reaction conditions, Beer’s law was obeyed in a concentration limit of 1～6 µg mL-1. The relative standard deviation was less than 2.9%. The apparent molar absoptivity was determined to be 1.86×104 L mol-1cm-1 at 425 nm. The CT complexation was also confirmed by both FTIR and 1H NMR measurements. The thermodynamic properties and reaction mechanism of the CT complexation have been discussed. The developed method could be applied successfully for the determination of the studied compound in its pharmaceutical dosage forms with a good precision and accuracy compared to official method as revealed by t- and F-tests.

Effect of Dynamic Crosslinking on Mechanical Properties of PP/EPDM Blends

1993 ◽  
Vol 58 (11) ◽  
pp. 2642-2650 ◽  
Author(s):  
Zdeněk Kruliš ◽  
Ivan Fortelný ◽  
Josef Kovář
Keyword(s):  
Mechanical Properties ◽  
Impact Strength ◽  
Shear Modulus ◽  
High Impact ◽  
Necessary Condition ◽  
Step Method ◽  
Melt Mixing ◽  
One Step ◽  
High Impact Strength ◽  
Dynamic Curing

The effect of dynamic curing of PP/EPDM blends with sulfur and thiuram disulfide systems on their mechanical properties was studied. The results were interpreted using the knowledge of the formation of phase structure in the blends during their melt mixing. It was shown, that a sufficiently slow curing reaction is necessary if a high impact strength is to be obtained. Only in such case, a fine and homogeneous dispersion of elastomer can be formed, which is the necessary condition for high impact strength of the blend. Using an inhibitor of curing in the system and a one-step method of dynamic curing leads to an increase in impact strength of blends. From the comparison of shear modulus and impact strength values, it follows that, at the stiffness, the dynamically cured blends have higher impact strength than the uncured ones.

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