Colorimetric detection of glyphosate: towards a handmade and portable analyzer

2020 ◽  
Vol 92 (4) ◽  
pp. 601-616
Author(s):  
Renata Hellinger ◽  
Valmir B. Silva ◽  
Elisa S. Orth
Keyword(s):  
Colorimetric Detection ◽  
Major Product ◽  
Field Analysis ◽  
Ambient Conditions ◽  
Time Analysis ◽  
Main Challenge ◽  
Colored Product ◽  
Hydrolysis Of ◽  
Colorimetric Reaction ◽  
Derivatization Reaction

AbstractGlyphosate (GFT) is a widely used herbicide, considered toxic and a probable carcinogen. The main challenge is its detection, usually requiring expensive and laborious methodologies. Herein, we report a colorimetric detection of GFT, using a derivatization reaction with 2,4-dinitrofluorobenzene (DNFB) that leads to a yellow-colored product. This is undertaken under mild conditions (weakly basic aqueous medium and ambient conditions). A thorough kinetic study was carried out, showing that the derivatization reaction with GFT predominates over the hydrolysis of DNFB. Hence, the colorimetric product is the major product formed, which was fully characterized by nuclear magnetic resonance. Finally, a portable, handmade and cheap colorimeter was used to detect and quantify GFT, relying on the colorimetric reaction proposed. Simulating real contaminated samples, it was possible to analyze in just 10 min, with less than 7 % of error of the nominal concentration. Overall, a highly sustainable approach is shown for an herbicide monitoring, with a simple and mild derivatization reaction that does not require purification and leads to a colorimetric product. Moreover, a simple apparatus with low time analysis is proposed that uses a problematic electronic trash: cellphone chargers. This cheapens the process and allows field analysis that can be extended to other agrochemicals.

Highly efficient hydrolysis of ammonia borane by anion (−OH, F−, Cl−)-tuned interactions between reactant molecules and CoP nanoparticles

2017 ◽  
Vol 53 (4) ◽  
pp. 705-708 ◽  
Author(s):  
Zi-Cheng Fu ◽  
Yong Xu ◽  
Sharon Lai-Fung Chan ◽  
Wei-Wei Wang ◽  
Fang Li ◽  
...  
Keyword(s):  
High Performance ◽  
Ammonia Borane ◽  
Ambient Conditions ◽  
Highly Efficient ◽  
Performance System ◽  
Hydrolysis Of ◽  
Nanoparticle Catalyst

An anion-assisted hydrolytic H2-releasing ultra-high performance system involving ammonia borane and a CoP nanoparticle catalyst has been established under ambient conditions.

scholarly journals Novel activity of angiotensin-converting enzyme. Hydrolysis of cholecystokinin and gastrin analogues with release of the amidated C-terminal dipeptide

1989 ◽  
Vol 262 (1) ◽  
pp. 125-130 ◽  
Author(s):  
P Dubreuil ◽  
P Fulcrand ◽  
M Rodriguez ◽  
H Fulcrand ◽  
J Laur ◽  
...  
Keyword(s):  
Angiotensin Converting Enzyme ◽  
Chloride Ion ◽  
Peptide Bond ◽  
Major Product ◽  
Enzyme Hydrolysis ◽  
Ion Concentration ◽  
Converting Enzyme ◽  
Rabbit Lung ◽  
Hydrolysis Of

ACE (angiotensin-converting enzyme; peptidyl dipeptidase A; EC 3.4.15.1), cleaves C-terminal dipeptides from active peptides containing a free C-terminus. We investigated the hydrolysis of cholecystokinin-8 [CCK-8; Asp-Tyr(SO3H)-Met-Gly-Trp-Met-Asp-Phe-NH2] and of various gastrin analogues by purified rabbit lung ACE. Although these peptides are amidated at their C-terminal end, they were metabolized by ACE to several peptide fragments. These fragments were analysed by h.p.l.c., isolated and identified by comparison with synthetic fragments, and by amino acid analysis. The initial and major site of hydrolysis was the penultimate peptide bond, which generated a major product, the C-terminal amidated dipeptide Asp-Phe-NH2. As a secondary cleavage, ACE subsequently released di- or tri-peptides from the C-terminal end of the remaining N-terminal fragments. The cleavage of CCK-8 and gastrin analogues was inhibited by ACE inhibitors (Captopril and EDTA), but not by other enzyme inhibitors (phosphoramidon, thiorphan, bestatin etc.). Hydrolysis of [Leu15]gastrin-(14-17)-peptide [Boc (t-butoxycarbonyl)-Trp-Leu-Asp-Phe-NH2] in the presence of ACE was found to be dependent on the chloride-ion concentration. Km values for the hydrolysis of CCK-8, [Leu15]gastrin-(11-17)-peptide and Boc-[Leu15]gastrin-(14-17)-peptide at an NaCl concentration of 300 mM were respectively 115, 420 and 3280 microM, and the catalytic constants were about 33, 115 and 885 min-1. The kcat/Km for the reactions at 37 degrees C was approx. 0.28 microM-1.min-1, which is approx. 35 times less than that reported for the cleavage of angiotensin I. These results suggest that ACE might be involved in the metabolism in vivo of CCK and gastrin short fragments.

Gas Turbine Fouling Offshore: Correction Methodology Compressor Efficiency

2017 ◽  
Author(s):  
Stian Madsen ◽  
Lars E. Bakken
Keyword(s):  
Gas Turbine ◽  
Peak Load ◽  
Operational Experience ◽  
Air Filtration ◽  
Ambient Conditions ◽  
Key Factors ◽  
Turbine Performance ◽  
Main Challenge ◽  
Filtration System ◽  
Compressor Efficiency

Gas turbine performance has been analyzed for a fleet of GE LM2500 engines at two Statoil offshore fields in the North Sea. Both generator drive engines and compressor driver engines have been analyzed, covering both the LM2500 base and plus configurations, as well as the SAC and DLE combustor configurations. Several of the compressor drive engines are running at peak load (T5.4 control), and the production rate is thus limited to the available power from these engines. The majority of the engines discussed run continuously without redundancy, implying that gas turbine uptime is critical for the field’s production and economy. Previous studies and operational experience have emphasized that the two key factors to minimize compressor fouling are the optimum designs of the inlet air filtration system and the water wash system. An optimized inlet air filtration system, in combination with daily online water wash (at high water-to-air ratio), are the key factors to achieve successful operation at longer intervals between offline washes and higher average engine performance. Operational experience has documented that the main gas turbine recoverable deterioration is linked to the compressor section. The main performance parameter when monitoring compressor fouling is the gas turbine compressor efficiency. Previous studies have indicated that inlet depression (air mass flow at compressor inlet) is a better parameter when monitoring compressor fouling, whereas instrumentation for inlet depression is very seldom implemented on offshore gas turbine applications. The main challenge when analyzing compressor efficiency (uncorrected) is the large variation in efficiency during the periods between offline washes, mainly due to operation at various engine loads and ambient conditions. Understanding the gas turbine performance deterioration is of vital importance. Trending of the deviation from the engine baseline facilitates load-independent monitoring of the gas turbine’s condition. Instrument resolution and repeatability are key factors for attaining reliable results in the performance analysis. A correction methodology for compressor efficiency has been developed, which improves the long term trend data for effective diagnostics of compressor degradation. Avenues for further research and development are proposed in order to further increase the understanding of the deterioration mechanisms, as well as gas turbine performance and response.

scholarly journals Enzymatic Hydrolysis of Polyester Thin Films: Real-Time Analysis of Film Mass Changes and Dissipation Dynamics

2015 ◽  
Vol 50 (1) ◽  
pp. 197-206 ◽  
Author(s):  
Michael Thomas Zumstein ◽  
Hans-Peter E. Kohler ◽  
Kristopher McNeill ◽  
Michael Sander
Keyword(s):  
Thin Films ◽  
Enzymatic Hydrolysis ◽  
Real Time ◽  
Time Analysis ◽  
Real Time Analysis ◽  
Hydrolysis Of

scholarly journals Gold Nanoparticles for Colorimetric detection of hydrolysis of antibiotics by penicillin G acylase

2010 ◽  
Vol 01 (04) ◽  
pp. 322-329 ◽  
Author(s):  
Neha R. Tiwari ◽  
Ambrish Rathore ◽  
Asmita Prabhune ◽  
Sulabha K. Kulkarni
Keyword(s):  
Gold Nanoparticles ◽  
Colorimetric Detection ◽  
Penicillin G Acylase ◽  
Penicillin G ◽  
Hydrolysis Of

scholarly journals Nanoporous Silica-Dye Microspheres for Enhanced Colorimetric Detection of Cyclohexanone

Chemosensors ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 34 ◽  
Author(s):  
Zheng Li
Keyword(s):  
Colorimetric Detection ◽  
High Surface ◽  
High Surface Area ◽  
Hierarchical Nanostructures ◽  
Practical Applications ◽  
Sensing Material ◽  
Nitro Explosives ◽  
Detection Of Explosives ◽  
Hydrolysis Of ◽  
Nanoporous Structures

Forensic detection of non-volatile nitro explosives poses a difficult analytical challenge. A colorimetric sensor comprising of ultrasonically prepared silica-dye microspheres was developed for the sensitive gas detection of cyclohexanone, a volatile marker of explosives 1,3,5-trinitro-1,3,5-triazinane (RDX) and 1,3,5,7-tetranitro-1,3,5,7-tetrazocane (HMX). The silica-dye composites were synthesized from the hydrolysis of ultrasonically sprayed organosiloxanes under mild heating conditions (150 °C), which yielded microspherical, nanoporous structures with high surface area (~300 m2/g) for gas exposure. The sensor inks were deposited on cellulose paper and given sensitive colorimetric responses to trace the amount of cyclohexanone vapors even at sub-ppm levels, with a detection limit down to ~150 ppb. The sensor showed high chemical specificity towards cyclohexanone against humidity and other classes of common solvents, including ethanol, acetonitrile, ether, ethyl acetate, and ammonia. Paper-based colorimetric sensors with hierarchical nanostructures could represent an alternative sensing material for practical applications in the detection of explosives.

A Bioinspired Dinickel(II) Hydrolase: Solvent Vapor-Induced Hydrolysis of Carboxyesters under Ambient Conditions

2016 ◽  
Vol 55 (24) ◽  
pp. 12696-12706 ◽  
Author(s):  
Suman K. Barman ◽  
Francesc Lloret ◽  
Rabindranath Mukherjee
Keyword(s):  
Ambient Conditions ◽  
Solvent Vapor ◽  
Hydrolysis Of

Dry ice-mediated rational synthesis of edge-carboxylated crumpled graphene nanosheets for selective and prompt hydrolysis of cellulose and eucalyptus lignocellulose under ambient reaction conditions

2020 ◽  
Vol 22 (16) ◽  
pp. 5437-5446 ◽  
Author(s):  
Hassan Idris Abdu ◽  
Kamel Eid ◽  
Aboubakr M. Abdullah ◽  
Mostafa H. Sliem ◽  
Ahmed Elzatahry ◽  
...  
Keyword(s):  
Graphene Nanosheets ◽  
Ambient Conditions ◽  
Selective Hydrolysis ◽  
Reaction Conditions ◽  
One Pot ◽  
Dry Ice ◽  
Hydrolysis Of Cellulose ◽  
Hydrolysis Of ◽  
Crumpled Graphene

Edge-carboxylated graphene (ECG) crumpled nanosheets with tuneable COOH content were synthesized by a facile one pot approach for selective hydrolysis of cellulose to glucose and eucalyptus to xylose and glucose under ambient conditions.

scholarly journals Development of a Coupled VanA/VanX Assay: Screening for Inhibitors of Glycopeptide Resistance

1997 ◽  
Vol 2 (4) ◽  
pp. 241-247 ◽  
Author(s):  
Steven D. Pratt ◽  
Xiaoling Xuei ◽  
Alexander C. Mackinnon ◽  
Angela M. Nilius ◽  
Dena M. Hensey-Rudloff ◽  
...  
Keyword(s):  
Enterococcus Faecium ◽  
High Throughput Screening ◽  
Colorimetric Detection ◽  
Glycopeptide Antibiotics ◽  
Glycopeptide Resistance ◽  
E Coli ◽  
Hydrolysis Of ◽  
Lac Promoter ◽  
Dipeptidase Activity ◽  
Coupled Assay

Resistance in Enterococcus faecium to the glycopeptide antibiotics vancomycin and teicoplanin is encoded by five genes: vanR, vanS, vanH, vanA, and vanX.1 The mechanism of resistance involves replacement of the dipeptide D-Ala-D-Ala, destined for the peptidoglycan layer with the depsipeptide D-Ala-D-lactate. This alteration lowers the binding affinity of vancomycin for the bacterial cell wall by a factor of 1000. The functions of VanA and VanX are the ligation of D-Ala and D-lactate, and the hydrolysis of D-Ala-D-Ala, respectively. We report here the overexpression of both genes as well as the D-Ala-D-Ala ligase (Ddl) from Enterococcus faecium, development of a coupled assay and several inhibitors obtained by high-throughput screening (HTS). All genes were expressed in E. coli by translational coupling to kdsB, the CMP-KDO synthetase gene, under control of a modified lac promoter. The coupled VanA/VanX assay employs colorimetric detection of inorganic phosphate (Pi) released in the VanA ligation reaction, with the VanX dipeptidase activity providing the D-Ala substrate for VanA. A secondary VanX assay uses cadmium-ninhydrin calorimetric detection of free amino acid released by the dipeptidase activity of the enzyme on D-Ala-D-Ala. We have also developed an assay using Ddl ligase. Over 250,000 compounds have been screened to date using the coupled assay.

Effect of high hydrostatic pressure on the enzymic hydrolysis of β-lactoglobulin B by trypsin, thermolysin and pepsin

1996 ◽  
Vol 63 (1) ◽  
pp. 111-118 ◽  
Author(s):  
Henrik Stapelfeldt ◽  
Per Hjort Petersen ◽  
Kristian Rotvig Kristiansen ◽  
Karsten Bruun Qvist ◽  
Leif H. Skibsted
Keyword(s):  
High Pressure ◽  
Hydrostatic Pressure ◽  
High Hydrostatic Pressure ◽  
Pressure Effect ◽  
Ambient Pressure ◽  
Apparent Volume ◽  
Enzymic Hydrolysis ◽  
Ambient Conditions ◽  
Β Lactoglobulin ◽  
Hydrolysis Of

SummaryHydrolysis of β-lactoglobulin B (β-lg B) by pepsin, a process slow at ambient conditions, is facilitated at a moderately high hydrostatic pressure such as 300 MPa, corresponding to an apparent volume of activation ΔV# = −63 ml mol−1 at pH 2·5, 30 °C and Γ/2=0·16. Digestion of β-lg by trypsin and thermolysin is likewise enhanced by pressure, and the pressure effect has been traced to pressure denaturation of β-lg B, which by high-pressure fluorescence spectroscopy has been shown to have a large negative volume of reaction, ΔV° = −98 ml mol−1, at pH 6·7, 30 °C and Γ/2 = 0·16. Pressure denaturation is only slowly reversed following release of pressure and the enhanced digestibility is maintained at ambient pressure for several hours.

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