Compact optical instrument for simultaneous determination of oxygen and carbon dioxide

Vargas-Sansalvador, Isabel M. Pérez de; Olmos, Ángel Delgado; Palma, A.; Fernández-Ramos, M.D.; Capitán-Vallvey, L.F.

doi:10.1007/s00604-010-0520-0

Cited by 21 publications

(16 citation statements)

References 26 publications

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“…It exploits a secondary inner-filter effect of a long lifetime luminophore dye, platinum octaethylporphyrin, inmobilized on PVCD membranes, by a pH indicator, α-naphtholphthalein. It is implemented in a portable instrumentation with both optoelectronic components coated with sensing chemistry (LED with the luminophore and photodetector with the pH-active dye) [29], and later integrated into a multi-analyte platform for oxygen and CO2 [30]. Contributing factors from both the chemical layer fabrication process and the optical detection system have significant impact on the sensitivity and reproducibility of the sensing device.…”

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confidence: 99%

A new light emitting diode–light emitting diode portable carbon dioxide gas sensor based on an interchangeable membrane system for industrial applications

Vargas-Sansalvador

Fay

Phelan

et al. 2011

Analytica Chimica Acta

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A new system for CO2 measurement (0-100%) by based on a paired emitter-detector diode arrangement as a colorimetric detection system is described. Two different configurations were tested: configuration 1 (an opposite side configuration) where a secondary inner-filter effect accounts for CO2 sensitivity. This configuration involves the absorption of the phosphorescence emitted from a CO2-insensitive luminophore by an acid-base indicator and configuration 2 wherein the membrane containing the luminophore is removed, simplifying the sensing membrane that now only contains the acid-base indicator. In addition, two different instrumental configurations have been studied, using a paired emitter-detector diode system, consisting of two LEDs wherein one is used as the light source (emitter) and the other is used in reverse bias mode as the light detector. The first configuration uses a green LED as emitter and a red LED as detector, whereas in the second case two identical red LEDs are used as emitter and detector. The system was characterised in terms of sensitivity, dynamic response, reproducibility, stability and temperature influence. We found that configuration 2 presented a better CO2 response in terms of sensitivity.Key words. Carbon dioxide sensor; Gas sensor; Optical sensor; Paired emitter detector-diode sensor; Portable instrumentation. INTRODUCTIONCO2 is an important industrial gas for many different uses that include production of chemicals (e.g. urea ), inert agent for food packaging (to extend the shelf-life of meat, cheese, etc.), beverages, refrigeration systems, welding systems, fire extinguishers, water treatment processes, and many other smaller scale applications [1;2]. In the agro-food industry CO2 is widely used in modified-atmosphere packaging where its task is to inhibit growth of spoilage bacteria [3;4]. For instance, in active packaging technologies a CO2 generating system can be considered as a technique complimentary to oxygen scavenging [5]. High CO2 levels (10-80 %) are desirable for foods such as meat and poultry in order to inhibit surface microbial growth and to extend their life time. The maintenance of CO2 concentration within packages in food [6], as instance using inserted sachets [7;8], must be carefully monitored since CO2 permeability is 3-5 times higher than that of oxygen for most of the plastic films and because CO2 is absorbed by many foods like meat and poultry. Real-time process monitoring is fundamental for effective process control. The rapid development of bioprocess applications together with the agro-food industry have led to an intensive search for new sensors capable of providing real-time information about the state of the processes. Conventional methods for CO2 determination include, among others, infrared spectrometry [9] or electrochemical sensors based on liquid (Severinghaus-type electrodes) or solid electrolytes [10;11]. The most popular sensors used for CO2 gas sensing in biotechnological applications are based on electrochemical measurements that can...

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confidence: 99%

A new light emitting diode–light emitting diode portable carbon dioxide gas sensor based on an interchangeable membrane system for industrial applications

Vargas-Sansalvador

Fay

Phelan

et al. 2011

Analytica Chimica Acta

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“…From this calibration curve, specifications such as the resolution and limit of detection (LOD) can be obtained. The resolution is calculated by taking derivatives on both sides of the equation and approximating these derivatives to increments [5] 2…”

Section: Figurementioning

confidence: 99%

“…The challenge now is to simplify the whole analysis system, avoiding the necessity for specialised training. Several studies can be found in the literature investigating alternatives to classic analytical methods, for instance, with the use of portable devices [2][3][4][5][6] or the novel usage of smartphones as detectors [7][8][9]. In this way, laboratory costs are reduced and there is no need for sample transportation.…”

Section: Introductionmentioning

confidence: 99%

Towards an autonomous microfluidic sensor for dissolved carbon dioxide determination

Sansalvador

López-Ruiz

Erenas

et al. 2018

Microchemical Journal

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In this work, we present a new system for the determination of dissolved carbon dioxide (from 7.2 ppm to 425.6ppm) in aqueous environments. Microfluidic technology has been incorporated in sensor design to reduce the volume of samples and reagents. Moreover, a detection system has been integrated in the chip, consisting of a white light-emitting diode as a light source and a high-resolution digital colour sensor as the detector, which are able to detect changes in colour produced by the reaction of the sensing chemistry and carbon dioxide in water.The optimised parameters found for the system are: flow rate 0.6 mL•min -1 , integration time 30 s and the time for pumping of solutions was 3 min, obtaining a LOD of 7.2 ppm. The CO2 response, reproducibility, precision, and stability of the sensing chemistry have been studied and compared with those obtained using benchtop instrumentation (i.e. a spectrophotometer), obtaining good agreement.

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“…The complexity increases further if more than on luminophore is present, and several parameters (e.g. [O 2 ], [CO 2 ], pH) have to be determined [5][6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Multi-Task Learning for Multi-Dimensional Regression: Application to Luminescence Sensing

Michelucci¹,

Venturini²

2019

Preprint

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The classical approach to non-linear regression in physics, is to take a mathematical model describing the functional dependence of the dependent variable from a set of independent variables, and then, using non-linear fitting algorithms, extract the parameters used in the modeling. Particularly challenging are real systems, characterised by several additional influencing factors related to specific components, like electronics or optical parts. In such cases, to make the model reproduce the data, empirically determined terms are built-in the models to compensate for the impossibility of modeling things that are, by construction, impossible to model. A new approach to solve this issue is to use neural networks, particularly feed-forward architectures with a sufficient number of hidden layers and an appropriate number of output neurons, each responsible for predicting the desired variables. Unfortunately, feed-forward neural networks (FFNNs) usually perform less efficiently when applied to multi-dimensional regression problems, that is when they are required to predict simultaneously multiple variables that depend from the input dataset in fundamentally different ways. To address this problem, we propose multi-task learning (MTL) architectures. These are characterized by multiple branches of task-specific layers, which have as input the output of a common set of layers. To demonstrate the power of this approach for multi-dimensional regression, the method is applied to luminescence sensing. Here the MTL architecture allows predicting multiple parameters, the oxygen concentration and the temperature, from a single set of measurements.

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Compact optical instrument for simultaneous determination of oxygen and carbon dioxide

Cited by 21 publications

References 26 publications

A new light emitting diode–light emitting diode portable carbon dioxide gas sensor based on an interchangeable membrane system for industrial applications

A new light emitting diode–light emitting diode portable carbon dioxide gas sensor based on an interchangeable membrane system for industrial applications

Towards an autonomous microfluidic sensor for dissolved carbon dioxide determination

Multi-Task Learning for Multi-Dimensional Regression: Application to Luminescence Sensing

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