Product category:
Chemical analysis equipment
News Release from: Hach Lange | Subject: LDO
Edited by the Laboratorytalk Editorial
Team on 21 June 2004
New technology for dissolved oxygen
Virtually maintenance-free system uses luminescence to asses dissolved oxygen, requiring no replacement of membranes or electrolyte or recalibration
The launch of a completely new technology for the measurement of dissolved oxygen is catching the attention of laboratory managers worldwide, and not least at Chester based Meadow Foods, which recently tested Hach Lange's new LDO dissolved oxygen meter For more than fifty years galvanic and polarographic sensors have been used to measure dissolved oxygen
This article was originally published on Laboratorytalk on 17 Sep 2008 at 8.00am (UK)
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These sensors employ membranes, anodes, cathodes, and electrolyte solutions that generally require a high degree of maintenance.
The sensors also suffer from drift, and as a result have to be recalibrated frequently.
Hach Lange has solved these long-standing problems with the launch of a sensor that, in contrast to its predecessors, does not consume oxygen as part of the measurement process, and does not require frequent recalibration because it does not suffer from drift (gradual loss of accuracy).
So, how does it work? The sensor is coated with a luminescent material, which is excited by blue light from an internal LED.
As the luminescent material relaxes it emits red light, and this luminescence is proportional to the dissolved oxygen present.
An internal red LED provides a reference measurement before every reading to ensure that the sensor's accuracy is maintained.
The LDO was assessed during September and October 2003, and found to be very easy to set up and simple to use.
The instrument was found to be robust in design and performed well under test, giving reproducible results during the testing period, says Hach Lange.
However, the main advantage of the LDO is the lack of maintenance required; it is not necessary to replace membranes or electrolyte, or to perform recalibration, which provides substantial cost savings.
The sensor cap is merely replaced once per year.
The internal batteries allow the LDO to be removed from its docking station and used in the field to determine DO levels in the receiving watercourse both upstream and downstream of the factory.
Nikki Mellor, Hach Lange's UK marketing manager, reports that "there has been massive interest in the LDO and it would appear that it will quickly dominate the markets for both laboratory and portable DO meters".
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