Development of a low cost microfluidic sensor for the direct determination of nitrate using chromotropic acid in natural waters

2015 ◽  
Vol 7 (13) ◽  
pp. 5396-5405 ◽  
Author(s):  
Deirdre Cogan ◽  
Cormac Fay ◽  
David Boyle ◽  
Conor Osborne ◽  
Nigel Kent ◽  
...  
Keyword(s):  
Natural Waters ◽  
Simple Procedure ◽  
Low Cost ◽  
Direct Determination ◽  
Chromotropic Acid ◽  
First Time

This study has demonstrated, for the first time, a microfluidic autonomous analyser for the direct determination of nitrate, incorporating a modified version of the chromotropic method resulting in a direct, quick, inexpensive and simple procedure to measure nitrate in situ.

scholarly journals Rapid in situ determination of ClO2 in drinking water by improved solid DPD spectrophotometry

2021 ◽  
Vol 252 ◽  
pp. 02063
Author(s):  
Qianqian Zhang ◽  
Lijun Jia ◽  
Tianli Hao ◽  
Ke Zeng
Keyword(s):  
Drinking Water ◽  
Low Cost ◽  
Direct Determination ◽  
Correlation Coefficients ◽  
Good Precision ◽  
Relative Standard ◽  
Relative Errors ◽  
Parallel Tests

This research aims to realize the rapid detection of ClO2 content in drinking water by adopting improved solid DPD. This method is fast and convenient with low cost and less waste liquid. The results show that this method has good precision and sensitivity. The linear correlation coefficients of the cubic regression equation were all greater than 0.999. The detection limit of the method was 0.002mg/L ClO2. The relative standard deviations (RSD) of seven parallel tests were between 1.37% and 8.87%, and the relative errors were small. The recovery rate was 96.67~110%. The method could be used for the direct determination of water samples with a mass concentration of 0.02mg/L~2.00mg/L in drinking water after ClO2 disinfection.

scholarly journals Direct Determination of Pyrazinamide (PZA) Susceptibility by Sputum Microscopic Observation Drug Susceptibility (MODS) Culture at Neutral pH: the MODS-PZA Assay

2020 ◽  
Vol 58 (5) ◽  
Author(s):  
Roberto Alcántara ◽  
Patricia Fuentes ◽  
Lisette Marin ◽  
Daniela E. Kirwan ◽  
Robert H. Gilman ◽  
...  
Keyword(s):  
Low Cost ◽  
Direct Determination ◽  
Drug Susceptibility ◽  
Turnaround Time ◽  
Content Type ◽  
Treatment Regimens ◽  
Neutral Ph ◽  
Molecular Tests ◽  
First Time

ABSTRACT Pyrazinamide (PZA) is considered the pivot drug in all tuberculosis treatment regimens due to its particular action on the persistent forms of Mycobacterium tuberculosis. However, no drug susceptibility test (DST) is considered sufficiently reliable for routine application. Although molecular tests are endorsed, their application is limited to known PZA resistance associated mutations. Microbiological DSTs for PZA have been restricted by technical limitations, especially the necessity for an acidic pH. Here, for the first time, MODS culture at neutral pH was evaluated using high PZA concentrations (400 and 800 μg/ml) to determine PZA susceptibility directly from sputum samples. Sputum samples were cultured with PZA for up to 21 days at 37°C. Plate reading was performed at two time points: R1 (mean, 10 days) and R2 (mean, 13 days) for each PZA concentration. A consensus reference test, composed of MGIT-PZA, pncA sequencing, and the classic Wayne test, was used. A total of 182 samples were evaluated. The sensitivity and specificity for 400 μg/ml ranged from 76.9 to 89.7 and from 93.0 to 97.9%, respectively, and for 800 μg/ml ranged from 71.8 to 82.1 and from 95.8 to 98.6%, respectively. Compared to MGIT-PZA, our test showed a similar turnaround time (medians of 10 and 12 days for PZA-sensitive and -resistant isolates, respectively). In conclusion, MODS-PZA is presented as a fast, simple, and low-cost DST that could complement the MODS assay to evaluate resistance to the principal first-line antituberculosis drugs. Further optimization of test conditions would be useful in order to increase its performance.

scholarly journals Direct determination of retrotransposon transposition rates in Drosophila melanogaster

1994 ◽  
Vol 63 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Sergey V. Nuzhdin ◽  
Trudy F. C. Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Element ◽  
Inbred Line ◽  
Copy Number ◽  
Direct Determination ◽  
Hybridization Analysis ◽  
Spontaneous Mutations ◽  
Insertion Sites

SummaryRates of transposition and excision of the Drosophila melanogaster retrotransposon elements mdg3, 297, Doc, roo and copia were estimated directly, by in situ hybridization analysis of their cytological insertion sites in 31 replicates of a highly inbred line that had accumulated spontaneous mutations for approximately 160generations. Estimated transposition rates of Doc, roo and copia were, respectively, 4·2 × 10−5, 3·1 × 10−3 and 1·3 − 10−3; no transpositions of 297 nor mdg3 were observed. Rates of transposition of copia varied significantly among sublines. Excisions were only observed for roo elements, at a rate of 9·0 × 10−6 per element per generation. Copy number averaged over these element families increased 5·9 %; therefore, in these lines the magnitude of the forces opposing transposable element multiplication were weaker than transposition rates.

scholarly journals A Simple, Rapid, Fluorometric Assay for Dopamine by In Situ Reaction of Boronic Acids and cis-Diol

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Xiaoxia Liu ◽  
Miaomiao Tian ◽  
Wenmei Gao ◽  
Jinzhong Zhao
Keyword(s):  
Low Cost ◽  
Boronic Acids ◽  
Emission Peak ◽  
Excitation Wavelength ◽  
Fluorescence Sensing ◽  
Serum Samples ◽  
Turn On ◽  
Rapid Reaction

An efficient, sensitive, and low-cost method has been developed for turn-on fluorescence sensing of dopamine (DA). The method relies on the rapid reaction of DA and 3-Hydroxyphenylboronic acid (3-HPBA) via specific recognition between boronic acids and cis-diol of DA in alkaline solution. The reaction product shows an excitation wavelength of 417 nm and the maximum emission peak at 470 nm. The proposed method allows the determination of DA in the range of 50 nM–25 μM, and the whole detection can be completed within 5 minutes. Furthermore, the presented approach has good selectivity and has been successfully applied to DA sensing in human serum samples, showing great potential in clinical diagnosis.

Fully automated, low-cost ion chromatography system for in-situ analysis of nitrite and nitrate in natural waters

Talanta ◽  
2020 ◽  
Vol 216 ◽  
pp. 120955 ◽  
Author(s):  
Eoin Murray ◽  
Patrick Roche ◽  
Matthieu Briet ◽  
Breda Moore ◽  
Aoife Morrin ◽  
...  
Keyword(s):  
Ion Chromatography ◽  
Natural Waters ◽  
Low Cost ◽  
In Situ Analysis

Bohrwiderstandsmessungen, eine neue und standardisierbare Methode zur Bestimmung der Kohäsion von Naturstein: Entwicklung eines Prototypes und dessen Erprobung / Drilling force measurement system, a new standardisa i methodology to determine the stone cohesion: Prototype design and validation

2000 ◽  
Vol 6 (2) ◽  
pp. 115-132 ◽  
Author(s):  
P. Tiano ◽  
C. Filareto ◽  
S. Ponticelli ◽  
M. Ferrari ◽  
E. Valentini
Keyword(s):  
Force Measurement ◽  
Direct Determination ◽  
Drilling Force ◽  
System A ◽  
Stone Materials ◽  
Force Measurement System ◽  
Drilling Resistance ◽  
Non Destructive

Abstract In the field of conservation of monumental buildings actually a standard methodology is lacking, with which it is possible to determine with the same sensitivity and reliability the "stone hardness" both at the superficial surface and at larger depths (few centimetres), both in laboratory and in situ. The use of the drilling resistance to determine the stone hardness is a very recent application and few working outdoor devices exist. The objective of this work is to validate a new and improved system to assess the drilling resistance of stones. The DFMS is portable and a quasi non-destructive device for direct determination of the "cohesion" of stone materials through the determination of their drilling resistance. The best operational features of the prototype have been established together with the assessment of the sensitivity and reliability of the system.

Sign in / Sign up

Export Citation Format

Share Document