IC analysis of disinfection by-products in ultrapure and drinking water samples
To maintain safe drinking water, a critical amount of
disinfectant must be added to kill pathogens while also
minimizing the production of DBPs to levels that are
below acceptable limits.
have set the maximum level of
bromate permissible in tap water at 10 μg/L. The FDA
adopts this same regulatory limit for bottled water.
In Europe, natural mineral waters and spring waters
treated by ozonation have a maximum permissible
bromate limit of 3 μg/L
; this value is 10 µg/L for
Levels of bromate, chlorate and
chlorite in drinking water are commonly assessed by IC
following EPA method 300.1.
We analyzed tap water and ultrapure water freshly
delivered from a Milli-Q
IQ 7000 system equipped
with a Millipak
?nal ?lter. Bromate, chlorate and
chlorite levels in the ultrapure water were below the
limits set by regulatory bodies (Table 2). Even if some
DBPs were present in the feed tap water, DBPs were
not detected in the ultrapure water dispensed from
The combination of technologies in the water
puri?cation chain (consisting of an Elix
system feeding a Milli-Q
IQ 7000 system) e?ciently
removes trace levels of DBPs to produce ultrapure
water that is suitable for drinking water analysis by IC.
Analyses were performed by an independent accredited
• Chlorite and chlorate: according to norm NF EN ISO
• Bromate: according to norm NF EN ISO 15061
• Eluent: carbonate/bicarbonate
• Column: Metrohm Metrosep A supp 7 – 250/4.0,
45 °C, suppressed conductivity detection
Table 2. Quanti?cation of DBPs in tap water (Guyancourt, France) and ultrapure water determined by
IC analysis, and compared to regulatory bodies limits for drinking water.
DBP Tap water Ultrapure water LOQ WHO guidelines
/ EPA MCL
Bromate (µg/L) 1 < LOQ 1 10 10 10
Chlorate (µg/L) 35 < LOQ 10 700 n/a 250
Chlorite (µg/L) < LOQ < LOQ 10 700 1 000 250
Suitability of ultrapure water produced by a Milli-Q
water puri?cation system for
the IC analysis of drinking water
This study demonstrates that ultrapure water freshly
produced by a Milli-Q
IQ 7000 water puri?cation
system is suitable for the tasks performed as part of
the IC analysis of drinking water. Speci?cally, for the
preparation of eluents, samples, and standards, and for
use as blanks. Even if the tap water feeding the system
contains the ions to be measured, these contaminants
are removed by the combination of technologies
present in the water puri?cation chain.
IQ 7000 ultrapure water system can be fed
by an Milli-Q
IX pure water system, which includes
EDI technology. Alternatively, a Milli-Q
7003/05/10/15 pure and ultrapure system dispenses
ultrapure water suitable for IC analysis using tap water
as its feed source.
Samples were tested by an independent accredited laboratory. Ultrapure water was delivered from a Milli-Q
IQ 7000 water puri?cation system.
EPA, US Environmental Protection Agency; FDA, US Food and Drug Administration; LOQ, Limit of Quanti?cation; MCL, Maximum Contaminant
Level; n/a, no data available; SOQ, Standards of Quality; WHO, World Health Organization.