chemiluminometer LUMIPOL 3

Lumipol 3 is an extremely sensitive photon counting instrument for measuring chemiluminescence with almost zero background signal. The instrument measures ultra weak light emissions accompanying reactions of various substrates usually of oxidation character.

The equipment may find wide use in both science and industry, especially where the problem of stability, stabilization and fatigue of polymers of other nonvolatile organic substrates are in the centre of research interest.

Features

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Temperature range: ambient to 250C
Accuracy of temperature: 0.25%
Mode of measurement: isothermal (intensity / time)
ramp - 87 steps programmable
period (intens./ temperature)
Maximum linear rate of heating: 20C/min
Measuring atmosphere: nitrogen, oxygen, air and mixtures of oxygen and nitrogen and other less reactive gases, possibility of connecting the gas mixture
Range of gas flow: 0 - 150 ml/min
Measuring mode: photon counting

Principle

inserting a sample
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The equipment unifies knowledge acquired in the study of chemiluminescence of organic substrates since 1960 by groups of researchers in Australia, Russia, United Kingdom, USA and the former Czechoslovakia (Polymer Institute of Slovak Academy of Sciences).

Chemiluminiscence results from the conversion of chemical energy into light which takes place in many elementary reactions of more complex reaction mechanisms. During oxidation the molecules of a reaction product which are formed in an excited state are either carbonyl compounds or singlet oxygen. These products are formed during recombination of peroxy radicals.

Characteristics

Power supply: 230VAC, max. 45W
Data connectors: counter 9-pin sub-D connector
(RS232 to COM1)
RS232 9-pin sub-D connector
(RS232 to COM2)
Computer requirements: Pentium, 800MHz, CD ROM, 2 free COM Ports, OS Windows 98 or higher
Background noise level: about 1 counts per second at 20C
Protection against daylight exposure: automatic mechanical shutter and software exposure protection
Mechanical specification: 445 x 500 x 760 mm (w x l x h)
Weight: 36 Kg
Inlet/outlet gas pipe diameter: 4 mm
Sample pans: Al, outer diameter 9.6 mm, inner diameter 9.4 mm, height 2.3 mm
Sample: powder, film, liquid
Sample mass: up to 30 mg

Software

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The instrument is connected to the controlling computer via two COM ports. The adjustment of controlling parameters and the collection of measured data is done via an application designed for OS Windows 98 or higher. The application is responsible for protecting the sensitive counting element against daylight exposure. If the application detects very high count levels, then it automatically disconnects high voltage from the counting element. The application includes a measurement-recovery capability that saves collected data and resumes a measurement in progress when there is a power failure or the controlling computer freezes. This feature is very important for long duration measurements. The collecting interval can be set from 1s to an arbitrary integer multiple. The application supports two measurement modes. The first mode is the isothermal mode. In this measurement mode intensity is collected at a constant temperature level. The second measurement mode is the Ramp mode, intensity is collected at a variable temperature level. The Ramp mode allows to set up a temperature curve that has up to 87 controlling points. The application contains a calibration capability. Collected intensity level can be calibrated using a light standard. Temperature is calibrated by two temperature standards. All functions and parameters, except raising/lowering of the measuring chamber, are available through the user interface of the application.

Applications

example measurement
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Lumipol 3 is suitable for detection and measuring of thermal oxidation of polymers or thermal decomposition of preoxidized polymers containing hydroperoxides from ambient temperature to 240C. The standard atmosphere is ensured by flow of gas at maximum rate of 150 ml/min. Extreme sensitivity, which is achieved by almost zero background noise, enables to measure the oxidation of polymers already at 40C and the tendency towards oxidation of organic substrates even in the so-called "induction period" may be well estimated.

example measurement
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The efficiency of various antioxidants and polymer stabilizers may thus be evaluated. The substrate examined may involve polymers, food components, edible oils and margarines, motor oils, paraffins, crude oil additives, inorganic materials, etc. The contamination of metal and ceramic surfaces may be detected and quantified as well.

example measurement
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Lumipol 3 is an effective analytical tool for testing, the life-service of materials in combination with ageing ovens and for determination of associated hydroperoxides in solid materials. It is possible to quantify surface homogeneity as well as to screen the efficiency of stabilizing systems without necessity to wait for the end of induction period of oxidation.