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ToxTracer™ Toxicity Analyzer

From:   Author:   Date:2011-10-26  

 ToxTracer system

 

Biological monitoring has become increasingly important for testing the quality of water. Various biological testing systems are available, however those using light emitting bacteria has proven to be the fastest and the most reliable. Skalar’s ToxTracer System is a bioassay based on the principle of inhibition of the natural bioluminescence of the marine bacterium Vibrio fischeri. Toxicants in the water sample inhibit the light emission of Vibro fischeri this is measured with the ToxTracer Luminometer. The speed of the system is due to the fast metabolism of the bacterial cell used by the ToxTracer, results can accomplished within 30 minutes.

In the marine environment bioluminescence is very common, bacteria produce most of the light. They are found free living in the water and as symbionts in specialized organs in certain fish, jelly fish and squids. The light emitted by the luminous bacteria is blue green in color, being confined to a rather narrow spectral band with a maximum near 490 nm.
The reaction is as follows:


FMNH2 + O2 + R-CHO FMN + H2O + R-COOH + Light


The easiest way to perform the test is using the reagent kit 2TT10451. The kit contains vials with freeze-dried bacteria of Vibrio fischeri strain NRRL B-111 77, which can be stored for almost a year in the freezer without loss of sensitivity. They should be considered as a biochemical, which you dissolve and subsequently use in an assay.

Principle of operation

The method is simple: First, the freeze-dried bacteria are reconstituted. While the bacteria equilibrate for 15 minutes, the sample is prepared: The osmotic value is adjusted and a dilution series prepared. Next the samples are added to the bacteria. After an exposure time of 5 to 30 minutes the light production is measured in the ToxTracer luminometer. If a reduction of the light emission is registered, toxic compounds are present. The analysis of the aqueous samples are performed under temperature controlled conditions. The system consists of a ToxTracer luminometer, a cooling block, and a reagent kit which includes the freeze-dried bacteria.

International standards require the use of either freeze-dried bacteria as well as freshly prepared bacteria. Skalar organises training courses in using freshly prepared bacteria for the test according to ISO 11348-1. The procedure with those bacteria provides the user with an almost inexhaustible source of bacterial reagent what is especially cost saving when many measurements have to be done. As compared to the freeze-dried bacterial preparations, the use of freshly prepared bacteria gives the user a better insight in the bio-availability of toxicants and improves the interpretation of the results.

The ToxTracer luminometer can act as a stand-alone instrument. During measurement the inhibition values are directly shown on the display of the luminometer. It is also possible to store the measured inhibition values on your PC by using the ToxTracer software. The results are expressed in a table and for the dilution series the data are plotted in a graph. Automatically the dilution at 50% inhibition is extrapolated from the graph. The results shown in this screen can be printed out as a report.

 

    

Skalar’s research team has vast experience in performing extraction techniques for food. They have developed unique methods for analysis with the aid of luminescing bacteria in the ToxTracer System. Skalar offers the availability of following practical courses in food analyses using the ToxTracer System. Micromethods are used and as there is no need for complex clean-up protocols,extractions and analysis are rapidly performed. The methods are particularly valuable in emergencies and in cases of sabotage.

Features
• Compact
• Easy to use
• Strong
• Stable cooling: 15°C ± 0.1°C
• Withstands environmental temperatures to 42°C
• If necessary use of a presence/absence test in dilution series
• Ready made reagent kit or training courses for the breeding of bacteria and making Standard Cell Suspensions available
• Unique methods for the analysis of water and food extracts

Applications fields
• Waste water
• Surface water
• Process waters
• Landfill leachates
• Soil and sediments
• Food
• Pharmaceuticals
• Cooling towers
• Cutting fluids