scholarly journals Innovations in High-Pressure Liquid Injection Technique for Gas Chromatography: Pressurized Liquid Injection System

2003 ◽  
Vol 41 (10) ◽  
pp. 550-559 ◽  
Author(s):  
J. Luong ◽  
G. Ronda ◽  
R. Tymko
1995 ◽  
Vol 715 (2) ◽  
pp. 279-285 ◽  
Author(s):  
S. Panda ◽  
Q. Bu ◽  
K.S. Yun ◽  
J.F. Parcher

2017 ◽  
Vol 68 (4) ◽  
pp. 666-670 ◽  
Author(s):  
Mirela Mihon ◽  
Catalin Stelian Tuta ◽  
Alina Catrinel Ion ◽  
Dana Niculae ◽  
Vasile Lavric

The aim of this work was the development and validation of a fast analytical method to determine the residual solvents content in radiopharmaceuticals such as: 18F-Fluorodeoxyglucose (18F-FDG), 18F-Fluoroestradiol (18F-FES), 18F-Fluorothymidine (18F-FLT),18F-Fluoromisonidazole (18F-FMISO). Radiopharmaceuticals are radioactive preparations for medical purposes used in nuclear medicine as tracers in diagnostic imaging and treatment of certain diseases. Positron Emission Tomography (PET) is a medical imaging technique that consists in introducing into the body of a small amount of a biologically active chemical compound labelled with a short lived positron-emitting radioisotope (18F, 11C, 68Ga). Residual solvents are critical impurities in radiopharmaceuticals that can affect labelling, stability and physicochemical properties of drugs. Therefore, the determination of these solvents is essential for quality control of radiopharmaceuticals. Validation of the control method for residual solvents by gas chromatography is referred by the European Pharmacopoeia using a special injection technique (head space). The parameters of the method, which comply with International Conference on Harmonization guidelines, are: accuracy, precision, linearity, limit of detection, limit of quantification and robustness. The proposed method (direct gas chromatography injection) proved to be linear, precise, accurate and robust. Good linearity was achieved for all the solvents and correlation coefficients (R2) for each residual solvent were found more than 0.99.


2021 ◽  
Author(s):  
Muhammad Zakwan Mohd Sahak ◽  
Eugene Castillano ◽  
Tengku Amansyah Tuan Mat ◽  
Maung Maung Myo Thant

Abstract For mature fields, water injection is one of the widely deployed techniques to ensure continuous oil recovery from the reservoir by maintaining the reservoir pressure, oil rim and pushing the oil from injection to production wells. Thus, it is critical to ensure a continuous and reliable operation of water injection to have consistent and sustainable rate. This paper demonstrates the new approach, utilizing automation and digital technology providing operational improvement and reduction in unplanned production deferment (UPD). One of the methods to effectively manage the water injection operation is via automation of injection process, especially since most of the water injection facilities still rely heavily on manual operation. First, a discussion on typical water injection technique is discussed. Challenges and sub-optimal operation of water injection processes within the company and industry are analysed. Then, the designing of a fully automated water injection system, such as equipment availability and constraints in matching and responding to well injection requirement are demonstrated. While an immediate adoption of process automation to mature assets may be faced with challenges such as system readiness, hardware availability, capital investment and mindset change, a step-by-step approach such as guided operation and semi-auto operation is explored as preparation prior to a full automation roll-out. With the shift from manual operation reliance to automation, the response time to process changes is improved leading to reduction in near-miss and trip cases, and minimum unplanned deferment.


2019 ◽  
Vol 52 (15) ◽  
pp. 193-198
Author(s):  
Florian Hartl ◽  
Jonas Brueckner ◽  
Christoph Ament ◽  
Julian Provost

2018 ◽  
Vol 173 (2) ◽  
pp. 3-8
Author(s):  
Mirosław KARCZEWSKI ◽  
Krzysztof KOLIŃSKI

Majority of modern diesel engines is fitted with common-rail (CR) fuel systems. In these systems, the injectors are supplied with fuel under high pressure from the fuel rail (accumulator). Dynamic changes of pressure in the fuel rail are caused by the phenomena occurring during the fuel injection into the cylinders and the fuel supply to the fuel rail through the high-pressure fuel pump. Any change in this process results in a change in the course of pressure in the fuel rail, which, upon mathematical processing of the fuel pressure signal, allows identification of the malfunction of the pump and the injectors. The paper presents a methodology of diagnosing of CR fuel injection system components based on the analysis of dynamic pressure changes in the fuel rail. In the performed investigations, the authors utilized LabView software and a µDAC data acquisition module recording the fuel pressure in the rail, the fuel injector control current and the signal from the camshaft position sensor. For the analysis of the obtained results, ‘FFT’ and ‘STFT’ were developed in order to detect inoperative injectors based on the curves of pressure in the fuel rail. The performed validation tests have confirmed the possibility of identification of malfunctions in the CR system based on the pressure curves in the fuel rail. The ‘FFT’ method provides more information related to the system itself and accurately shows the structure of the signal, while the ’STFT’ method presents the signal in such a way as to clearly identify the occurrence of the fuel injection. The advantage of the above methods is the accessibility to diagnostic parameters and their non-invasive nature.


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