scholarly journals Study on the Stability of Antibiotics, Pesticides and Drugs in Water by Using a Straightforward Procedure Applying HPLC-Mass Spectrometric Determination for Analytical Purposes

Separations ◽  
2021 ◽  
Vol 8 (10) ◽  
pp. 179
Author(s):  
Salvatore Barreca ◽  
Carola Forni ◽  
Luisa Colzani ◽  
Laura Clerici ◽  
Daniela Daverio ◽  
...  
Keyword(s):  
Surface Water ◽  
Method Development ◽  
Solid Phase ◽  
Direct Injection ◽  
Residue Analysis ◽  
Solvent Mixture ◽  
Mass Spectrometric ◽  
Operating Conditions ◽  
Sampling Station ◽  
The Stability

The stability of analytes is a critical point in chemical analysis, especially in the field of trace levels residue analysis. Nowadays, due to advances in analytical technology and in separation sciences, the analyses of water have been improved. Unfortunately, in this context, one of the most critical issues in water analysis include compound stability from sampling station to laboratory procedures. This study was carried out to explore the stability of several compounds in water from sampling to analysis concerning analytes reported in implementing decision 2018/840—Watch List. During method development and validation, the stability of compounds was investigated to detect the best operating conditions concerning sampling, extraction and analysis. In this paper, we report a study on the stability of antibiotics, pesticides and drugs in water determined using a straight-forward procedure applying mass spectrometric detection for analytical purposes. The laboratory tests were performed in Milli-Q water and surface water by analyzing samples through direct injection, solvent mixture (Water/ACN) and solid phase extraction system from time 0 to 168 h. All the analytes of the WL are stable in aqueous solutions with the addition of at least 25% ACN even after 168 h, and the analytes have shown a matrix effect on recovery of some analytes such as Famoxadone from sampling results (recovery in surface water 72%). For all the analytes investigated, recoveries were between 70 and 130% by using SPE procedures before UHPLC-MS/MS analysis, which is in good agreement with method validation procedures.

Thermoacoustic Stability Analysis of a Kerosene-Fueled Lean Direct Injection Combustor Employing Acoustically and Optically Measured Transfer Matrices

2012 ◽  
Author(s):  
Bernhard C. Bobusch ◽  
Jonas P. Moeck ◽  
Christian Oliver Paschereit ◽  
Sermed Sadig
Keyword(s):  
Stability Analysis ◽  
Transfer Functions ◽  
Direct Injection ◽  
Network Models ◽  
Operating Conditions ◽  
Transfer Matrices ◽  
Test Rig ◽  
Lean Direct Injection ◽  
Calibration Measurement ◽  
The Stability

The assessment of the stability characteristics of kerosene-fueled, lean direct injection flames is an important issue for the design of low-emission aircraft engine combustion systems. To achieve this task, acoustic network models are widely used. In the present work, this technique is applied to determine the stability behavior of a liquid-fueled, lean direct injection combustor. The required transfer matrices have been measured in an atmospheric combustion test rig. The burner transfer matrix as well as the upstream and downstream reflection coefficients are obtained by using the multi-microphone method. Since the measurement of flame transfer functions for liquid-fueled flames is a complex task, two techniques are applied and compared. First, the flame response to loudspeaker forcing is measured with the multi-microphone technique. Second, a technique based on the simultaneous acquisition of different chemiluminescence signals is applied. The chemiluminescence response at four different wavelengths (310 nm, 407 nm, 431 nm, and 515 nm), corresponding to the species OH*, CH*, CO2* and C2*, respectively, are measured using photomultiplier tubes. With a calibration measurement at different operating conditions, it is possible to calculate the instantaneous heat release rate. Flame transfer functions and matrices are measured in the test rig with the two techniques. Additionally, all acoustically measured transfer matrices and optically measured transfer functions are used to predict possible unstable modes in the test rig. The experimental results and the stability analysis employing the measured flame transfer functions are in good agreement and demonstrate validity of the method.

scholarly journals Multi-residue analysis of polar pesticides in surface water and sediment by high performance liquid chromatography

2015 ◽  
Vol 18 (2) ◽  
pp. 159-165
Author(s):  
Hai Lam Son Truong ◽  
Trang Thi Thuy Nguyen ◽  
Huyen Ngoc Tran ◽  
Trang Thi Nhu Tran
Keyword(s):  
Surface Water ◽  
High Performance ◽  
Solid Phase ◽  
Residue Analysis ◽  
Complex Matrix ◽  
Quechers Method ◽  
Sediment Samples ◽  
Polar Pesticides ◽  
Water And Sediment ◽  
Cleanup Procedure

We have successfully studied the analytical method of polar pesticides like carbofuran, pirimicarb, thiodicarb, atrazine, simazine, carbaryl, diuron, isoprocarb in surface water and sediment by HPLC-UV. The method could be applied to HPLC- MS. The stable recoveries ranged from 79 – 110 % with surface water and sediment samples. Especially, a cleanup procedure combined QuEChERS method and solid phase extraction has been developed to analyse these compounds in sediment, a very complex matrix.

TEM characterization of Au/Polysilicon interactions

1990 ◽  
Vol 48 (4) ◽  
pp. 650-651
Author(s):  
N. David Theodore ◽  
Leslie H. Allen ◽  
C. Barry Carter ◽  
James W. Mayer
Keyword(s):  
Solid Phase ◽  
Single Crystal Silicon ◽  
Chemical Vapor ◽  
Electrical Contacts ◽  
Silicon Substrates ◽  
Crystal Silicon ◽  
Transmission Electron ◽  
Polysilicon Films ◽  
The Stability

Metal/polysilicon investigations contribute to an understanding of issues relevant to the stability of electrical contacts in semiconductor devices. These investigations also contribute to an understanding of Si lateral solid-phase epitactic growth. Metals such as Au, Al and Ag form eutectics with Si. reactions in these metal/polysilicon systems lead to the formation of large-grain silicon. Of these systems, the Al/polysilicon system has been most extensively studied. In this study, the behavior upon thermal annealing of Au/polysilicon bilayers is investigated using cross-section transmission electron microscopy (XTEM). The unique feature of this system is that silicon grain-growth occurs at particularly low temperatures ∽300°C).Gold/polysilicon bilayers were fabricated on thermally oxidized single-crystal silicon substrates. Lowpressure chemical vapor deposition (LPCVD) at 620°C was used to obtain 100 to 400 nm polysilicon films. The surface of the polysilicon was cleaned with a buffered hydrofluoric acid solution. Gold was then thermally evaporated onto the samples.

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