In-situ measurement of oxygen concentration under high pressure and the application to oxygen permeation through polymer films (original) (raw)
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Permeability of oxygen through polymers. I. A novel spectrophotochemical method
Journal of Applied Polymer Science, 1979
A novel method for the measurement of oxygen permeability through polymer membranes is described. It is based on monitoring the sensitized photo-oxygenation of a singlet oxygen acceptor in a detector layer sandwiched between a support and the polymer layer under test. The detector layer contains a sensitizer which on irradiation produces singlet excited oxygen from the ground-state oxygen available. The singlet oxygen reacts with an oxygen acceptor, the disappearance of which can be followed by spectrophotometry. In the photostationary state, changes in the acceptor absorbance are directly related to the overall flux of oxygen through the polymer membrane. It can be shown that the permeation coefficient P of oxygen is proportional to the rate of change in acceptor absorbance and to the inverse of the oxygen concentration in the surrounding atmosphere. It is given by the expression 1 AD1 p=- .-103tAC At where t is the molar extinction coefficient, AC is the difference in the oxygen concentration on the two sides of the polymer membrane, AD is the change in optical density during the time interval At, and 1 is the thickness of the polymer membrane. The method is comparatively simple and rapid and provides data for polymers that are difficult to study by more conventional methods. Oxygen permeabilities were measured for a group of water-soluble polymers.
A fibre optic fluorescence quenching oxygen partial pressure sensor using PtOEP
Received XX Month XXXX; revised XX Month, XXXX; accepted XX Month XXXX; posted XX Month XXXX (Doc. ID XXXXX); published XX Month XXXX The development and bench testing of a fibre optic oxygen sensor is described. The sensor is designed for measurement of tissue oxygen levels in the mucosa of the digestive tract. The materials and construction are optimised for insertion through the mouth for measurement in the lower oesophagus. An oxygen sensitive fluorescence quenching film was applied as a solution of platinum octaethylporphyrin (PtOEP) poly(ethyl methacrylate) (PEMA) and dichloromethane and dip coated onto the distal tip of the fibre. The sensor was tested by comparing relative fluorescence when immersed in liquid water at 37 °C, at a range of partial pressures (0 – 101 kPa). Maximum relative fluorescence at most oxygen concentrations was seen when the PtOEP concentration was 0.1 g.L-1, four layers of coating solution were applied and a fibre core radius of 600 μm was selected, giving a Sterm-Volmer constant of 0.129 kPa-1. The performance of the sensor is suitable for many in-vivo applications particularly mucosal measurements. It has sufficient sensitivity, is sterilisable and is sufficiently flexible and robust for insertion via the mouth without damage to the probe or risk of harm to the patient.
Very fast sensors that are able to track rapid changes in oxygen partial pressure (PO2) in the gas and liquid phases are increasingly required in scientific research – particularly in the life sciences. Recent interest in monitoring very fast changes in the PO2 of arterial blood in some respiratory failure conditions is one such example. Previous attempts to design fast intravascular electrochemical oxygen sensors for use in physiology and medicine have failed to meet the criteria that are now required in modern investigations. However, miniature photonic devices are capable of meeting this need. In this article, we present an inexpensive polymer type fibre-optic, oxygen sensor that is two orders of magnitude faster than conventional electrochemical oxygen sensors. It is constructed with biologically inert polymer materials and is both sufficiently small and robust for direct insertion in to a human artery. The sensors were tested and evaluated in both a gas testing chamber and in a flowing liquid test system. The results showed a very fast T90 response time, typically circa 20 ms when tested in the gas phase, and circa 100 ms in flowing liquid.
Journal of Food Engineering, 2016
An optical sensor for oxygen detection based on the immobilization of tris 1,10-phenanthroline ruthenium (Ru(phen) 3) into polystyrene (PS) films was employed for monitoring the oxygen permeation through polymeric packaging films. 7-Methoxy-4-methylcoumarin was selected as non-sensitive reference to oxygen and dispersed with the Ruthenium complex in order to develop a ratiometric sensor correcting the artefacts induced by operating conditions and improving the robustness of the sensor. The developed ratiometric sensor was successfully employed for the measurement of the oxygen permeation rate in an enclosed atmosphere (package) using polymeric films made of biaxially oriented polypropylene (BOPP) and polydimethyl siloxane (PDMS). It was observed that the oxygen concentration in the enclosed atmosphere increased from 0% to 21% in 3 hours in the case of PDMS and from 0% to 3.6% in 24 hours for BOPP. The concentration evolvement with time was well predicted by a solutiondiffusion model and the final oxygen concentration in the packed atmosphere was confirmed by chromatographic measurements. According to these results, the ratiometric luminescent sensor is suitable for the development of smart packaging films allowing for continuous monitoring of oxygen concentration in-situ. Highlights • Development of robust ratiometric luminescent sensor • Non-invasive and on-line monitoring of oxygen in food packaging • In-situ measurement of oxygen permeation trough packaging materials • Predicting oxygen concentration in food packaging using molecular probes
The unsteady-state measurement of polymer membrane permeability to dissolved oxygen
Journal of Membrane Science, 1989
A theoretical analysis is presented on the unsteady-state measurement of polymer membrane permeability to dissolved oxygen by means of an analyzer fitted with an oxygen electrode. The main conclusions of this analysis are as follows: (i) the oxygen mass balance must take into account the rate of oxygen consumption at the electrode; (ii) the apparent permeability coefficient Q can be derived by the unsteady-state technique provided that the quasi-steady-state condition is fulfilled for the gas transport in the membrane phase; (iii) the true permeability coefficient P can be evaluated by a set of experiments performed on a single polymeric film using the apparent permeability Q obtained at various rates of stirring.
A new technique to quantify oxygen diffusion in polymer films
Macromolecules, 1992
Diffusion Coefficients for oxygen in polymer films are quickly and accurately obtained by using a near-infrared luminescence spectrometer. The spectroscopic technique described herein uses the 1270-nm phosphorescence of singlet molecular oxygen (l $ 0 2-32,-02) to directly monitor oxygen sorption into polymer films (15-80 Fm thick) of small area (-1 cm X 1 cm). The approach is illustrated by using films of polystyrene for which a 25 "C diffusion coefficient of (2.3 f 0.3) x cm2/s is obtained.
Optimisation of a polymer membrane used in optical oxygen sensing
Sensors and Actuators B: Chemical, 2004
A method for detection of viable cells utilises a sensor based on the optical measurement of oxygen consuming by cells. Changes in the oxygen level were measured via quenching of the fluorescence of an oxygen-sensitive fluorophor (Ru(dpp) 3 Cl 2 ). The fluorescence lifetime changing was measured in accord with Stern-Volmer equation, using a phase-shift method. The fluorophor was embedded into a polysulfone membrane that is in contact with the cell medium. The sensitivity of oxygen sensor depends on behaviour of polysulfone membrane. Manufacturing method, type of polysulfone and concentration of fluorophor can also change this behaviour. These parameters were explored to obtain the optimum analytical performance, and the optimum sensitive membrane was chosen for 3 mmol/l concentration of fluorophor, when a linear plot was obtained with R = 0.99987 for a sensitivity of 12.11 ± 0.11 mV/% O 2 (n = 5).
Evaluation of Oxygen Permeability of Polyethylene Films
2012
The paper dealt with the evaluation of the oxygen permeability of the polyethylene films applied in the mulching and food packaging. The construction of the equipment is discussed. The design and the construction of the equipment was realized with applying of the standard EN STN 77 0333.The measurement of the permeability of the oxygen trough the polyethylene Bralen 2–63 with 9% colored concentrate Maxithen HP 533041 – violet film was realized by means of modified method. The values of the permeability Px, 1794.25 cm 3 ·m –2 ·d –1 . (0.1 MPa) –1 of the oxygen trough the film of the
Instrumental Aspects of Oxygen Sensing: Quantitation and Recalibration of a Biofouled Oxygen Sensor
2017
In vivo oxygen sensing is a critical area of research for medical applications, such as ischemic stroke, but this important topic is not fully understood or resolved. In addition, the best method for calibration of in vivo sensors is as yet undetermined. For all implantable devices, biofouling, the adsorption of biological material to the device surface, is another significant problem with no clear or well-defined solution. One method employed is to apply a protective polymer membrane to the sensor surface in order to minimize the adsorption of biological material. The work described here investigates two polymers applied to a gold electrode for oxygen sensing: polyeugenol (PE) and poly-o-phenylenediamine (PoPD). Polyeugenol, while permeable to oxygen, and unhampering to the overall oxygen sensitivity for the sensor, shows polymer instability, and is therefore not applicable to long-term in vivo sensors. PoPD is shown in these works to be both permeable to oxygen and mechanically st...
Oxygen pressure measurement using singlet oxygen emission
Review of Scientific Instruments, 2005
Pressure sensitive paint ͑PSP͒ provides a visualization of two-dimensional pressure distributions on airfoil and model automobile surfaces. One type of PSP utilizes platinum tetra͑pentafluorophenyl͒porphine ͑PtTFPP͒ dissolved in a fluoro-polymer film. Since the intense 650 nm triplet emission of PtTFPP is quenched by ground state oxygen, it is possible to measure two-dimensional oxygen concentration from the 650 nm emission intensity using a Stern-Volmer-type relationship. This article reports an alternative luminescence method to measure oxygen concentration based on the porphyrin-sensitized 1270 nm singlet oxygen emission, which can be imaged with an InGaAs near infrared camera. This direct measurement of oxygen emission complements and further validates the oxygen measurement based on PtTFPP phosphorescence quenching. Initial success at obtaining a negative correlation between the 650 nm PtTFPP emission and the 1270 nm O 2 emission in solution led us to additional two-dimensional film studies using surfaces coated with PtTFPP, MgTFPP, and H 2 TFPP in polymers in a pressure and temperature controlled chamber.