New Automatic Methods in Water Testing

By Brian Wili and David Thomerson
April 1999

Brian Wili is Director and David Thomerson is Sales and Marketing Manager at Burkard Scientific, a company that manufactures professional analytical systems. Based in the UK and providing a comprehensive range of instruments for automatic analysis, the company policy is to study carefully the needs of the operator while maintaining the strict requirements of present day water testing.

The Role of Laboratory and On-Line Automated Systems

For the sake of the environment, world health and improvement in living standards water quality is vital, and the role of automation in today´s water laboratories is becoming more significant. Because of the range of pollutants that affect our rivers, lakes, fresh and sea water sources an ever increasing volume of water samples needs to be regularly examined. Soil, sewage and food products must undergo a similar stringent control to meet the established international standards. So it is not surprising that there is continual world-wide demand for modern test equipment.

Many types of analysis instruments are offered for water quality test procedures both in the laboratory and for remote on-site monitoring stations. The choice is often one of Segmented Flow continuous analysis, Flow Injection, Chromatography or Electrode techniques. Most would agree that continuous analysis by segmented flow analysers (SFA) have shown this type of instrumentation to be perhaps the most reliable and cost effective: for routine sample analysis. The flexibility of the system enables both large and small sample batches to be processed with equal convenience.

For the technician, this means that the equipment should be attractive to use and easy to operate. The instruments should be designed for long life with minimal servicing.

For the water consumer, there is the assurance of reaching the specified limits of detection. Impurity down to parts per billion is the norm for many samples regularly examined.

The analytical capability is continually under review together with the chemistry methodologies, to comply with the changing international standards.

Burkard Scientific SFA-2000 is the well proven continuous flow analyser which is multi-tasking. It has been installed worldwide for use in Water, Forestry, Agriculture and Atomospheric Pollution laboratories in heavy industrial areas. The degree of sophistication will depend on a variety of factors including the type and concentration of the analyte under test, as well as the size of the batches being analysed.

As the system is modular it has many attractive features. Each unit of the system benefits from the latest technology and lends itself to updating without major reconstruction. Again, individual components make for the utmost flexibility where a combination of Sample Changer capacity, number of analytical channels, pumping capacity, and type of chemistry detection can be selected to suit the user´s needs.

New Analytical Methods

Burkard Scientific constantly addresses the new problems presented by industrial processes in the form of effluents. Detergent levels in rivers are regularly a cause for concern where the European standard has been set at 250µg/litre.

In this situation a method was developed to overcome time-consuming manual testing, which normally processes samples at rates of 10 to 15 per day. A new automated approach to the analysis involving considerable method development was undertaken. The anionic detergent complexes with methylene blue in alkaline solution to produce a blue complex which is extracted into chloroform. The extract is then washed with an acid solution of methylene blue before being measured at 660nm using a colorimeter. Figure 1 shows the standards and calibration graph for the range 20-250 micro-g/l. Analysis times are now reduced to 20 samples per hour with a much reduced technician time, making the test a routine undertaking.

For tests such as Phenols, Cyanide and Fluoride from water and contaminated land samples an 'on-line' distillation facility is offered with U.V. digestion.

Helping the Brazilian Rain Forests

The Amazonian Rain Forests are yet another example of use of the use of the SFA-2000 system. A joint Anglo-Brazilian project to assess the presence of soil nutrients in a forest management scheme was set up in Manaus.

A 4-channel analyser is operated by local technicians to look at nutrient parameters such as Boron, Phosphorous, Aluminium and Ammonia. It is expected that the information gathered here will make a valuable contribution to maintaining forests in this area.

Off Shore Activities

Environmentalists and governmental departments concerned about pollution of the oceans and waterways need to be kept updated on the state of sea water. SFA-2000 analysers provide data on nutrient levels and are used by Oceanographic Scientists for survey work in all parts of the world.

Data Collection and Processing

Daily testing not only involves the setting up of the analysers, but in large laboratories where the work load is considerable, data processing is an essential element to full automation. The Burkard MICROSTREAM is one such data base which enhances the power and performance of any system.

MicroStream is a 4- or 8- Channel model in a range of PHA peak height analysers designed for processing signals from analytical equipment which are fed with material from automatic samplers. The data system runs in real time, performing all peak analysis and calculations 'on the fly'.

It can be attached to practically any equipment where samples are presented to the system at regular intervals. It is particularly suitable for continuous-flow analysers.

MicroStream is capable of being used as a Systems Manager to start up and close down an analyser at set periods during the day unattended. It is the product of 15 years experience with the water industry.

Year by year there is an increasing awareness of the urgent need to keep our waters pure. Yet, year by year contamination increases both in strength and complexity. Demands on laboratories are increasing and higher standards of detection are demanded. For the foreseeable future, continuous flow systems will play their part in the modern laboratory where sometimes less sophistication is more successful and cost-efficient.


Copyright © 1999, ECO Services International