About water

Clean water is the most important chemical reagent in a laboratory. Hydrolab offers systems producing water fitting the parameters of every water purity class, specified in PN-EN ISO 3696:1999, ASTM, CLSI, FP IX standards.

Water quality in a modern laboratory, depending of a usage purpose, should remain unchanged and proper, and its parameters (for example conductivity and temperature) should be constantly monitored. Basic standard of water quality in force in Poland are ISO 3696:1999 for analytical laboratories, and Farmakopea IX for pharmaceutical. The PN-EN ISO 3696:1999 standard describes three classes of water purity:


Class 1

Water without diluted contamination (colloidal ionic or organic), fitting the strictest analytical requirements, including a high-performance liquid chromatography. It is advised to obtain it from second purity class water, treating it with further processes (for example reverse osmosis or deionization, and then filtering through 0,2μm membrane for substance removal, or double distillation in a quartz apparatus). 


Class 2

Water with very low non-organic, organic and colloidal contamination. Should be obtained by a distillation, or a distillation forwarded by a deionization or a reverse osmosis.


Class 3

Water for general purposes, used for "wet" chemical tasks. Obtained by a single distillation, a deionization or a reverse osmosis.


ISO 3696:1999
ParameterClass 1Class 2Class 3
pH value n/a n/a 5,0-7,5
Conductivity µS/cm <0,1 <1 <5
254nm absorbance, 1cm absorbing layer thickness <0,001 <0,01 n/a
Remains after evaporation in a temp. 110 ºC mg/kg n/a <1 <2
silica mg/l <0,01 <0,02 n/a


Farmakopea IX
ParameterPurified water PWHighly purified water HPW
Conductivity, µS/cm in 25 ºC <4,8 -
TOC, ppb C <500 <500
Nitrates, ppm <0,2 <0,2
Heavy metals, ppm jako Pb <0,1 <0,1
Bacteria, cfu/ml <100 <10