Milestone’s duoPUR lower costs and increase ROI for water testing labs

Empresa Portuguesa das Águas Livres (EPAL)


Empresa Portuguesa das Águas Livres (EPAL) is based in Portugal and supplies water to approximately three million people in 35 municipalities, with 34 thousand direct customers in the city of Lisbon. EPAL specializes in water supply and wastewater treatment and has two accredited labs that perform daily water quality monitoring to ensure the public supply of water for human consumption. They analyze about 300,000 samples and collect more than 1,000 sampling points each year.


Before purchasing the ICP-MS, commercial nitric acid was used for all analytical methods for metals detection.
EPAL purchased an ICP-MS to perform trace metals analysis of water. This analysis could not be done with common analytical commercial concentrated nitric acid. As a result, the lab had to purchase expensive high-purity commercial nitric acid.
The duoPUR system is a very easy way to have high purity nitric acid available at a low cost. EPAL considers the duoPUR system an indispensable tool for trace analysis of metals in our laboratory”
Dr. João Paiva, Inorganic Chemistry Lab @ EPAL
  • Empresa Portuguesa das Águas Livres (EPAL)


The duoPUR has proven to be an efficient, reliable instrument, producing a continuous supply of high purity acid during each run. The acid is contained in quartz vessels and inserts, which lowers blank levels and reduces reagent contamination. “It has been possible to lower some of our quantification limits as the quality of the acid produced decreased the metal content in the blanks of these techniques.” The nitric acid produced is evaluated on a routine basis and the results have shown that the quality of the produced acid is equivalent or better than the commercial acid that had previously been used. Maintenance procedures for the duoPUR are easy to perform. The system is cleaned once a month by distillation of laboratory grade water and a preventive maintenance is performed annually by Milestone's supplier in Portugal.

duoPUR and subPUR

Milestone has developed the duoPUR and subPUR, sub-boiling distillation systems which allow laboratories to make their own high purity acids at dramatically reduced costs.

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"The greatest advantage of this system is the quality to cost ratio of the acid produced. From our experience, this system has a pay back within two years (routine basis)."
Empresa Portuguesa das Águas Livres (EPAL)