⚗️ Bromate in Water — Ion Chromatography

Physicochemistry PN-EN ISO 15061

Overview

STATUS (as of 03.11.2026). PN-EN ISO 15061:2003 — Polish version, published on 29.08.2003, implements EN ISO 15061:2001 and ISO 15061:2001 [IDT]; it replaced the English version PN-EN ISO 15061:2002. The PKN catalogue card has no note of withdrawal. ISO 15061:2001 (first edition) is published in the ISO catalogue with the stage “to be revised” (90.92); the iTeh catalogue shows no newer edition or draft. The standard covers bromate only — bromide is determined according to PN-EN ISO 10304-1 (a separate method in the Knowledge Base: dissolved anions in water), and the method with post-column reaction is described in PN-EN ISO 11206.

SCOPE (clause 1). Dissolved bromate in water, e.g. drinking water, raw water, surface water, partially treated water and swimming pool water. Appropriate pretreatment of the sample — elimination of chloride, sulfate and metals, preconcentration or dilution — gives a range of applicability from 0.5 µg/l to 1000 µg/l of bromate. The working range is restricted by the ion-exchange capacity of the concentrator column and of the separator column; if necessary, the sample is diluted.

PRINCIPLE (clause 4). Sample pretreatment removes ozone and solids and reduces chloride, sulfate, carbonate, hydrogen carbonate and metals by means of cation exchangers. Bromate is separated by liquid chromatography on an anion exchanger — on the separator column or after elution from a concentrator column; the eluents are usually aqueous solutions of salts of weak mono- and dibasic acids. It is measured with a conductivity detector with chemical suppression, while a UV detector (190–205 nm) is suitable only to confirm the result. Strongly retained ions (nitrate, phosphate, sulfate) are removed from the column with a more concentrated eluent; the concentration is determined after calibration of the overall procedure.

ESSENTIAL MINIMUM REQUIREMENTS (clauses 5 and 8). Recovery of bromate with preconcentration 80–120 %. Peak resolution between bromate and the nearest peak (usually chloride) of at least 1.3, calculated as R = 2(tR2 − tR1)/(w1 + w2), where tR are the retention times and w the peak widths at the base. Conductivity detection with chemical suppression, calibration according to ISO 8466-1 or ISO 8466-2, a validity check of the calibration function; if necessary, replicate determinations and, with matrix interferences, the method of standard addition.

INTERFERENCES (clause 3). Nitrate, chloride, carbonate and sulfate may reduce the capacity of the concentrator column and the recovery of bromate; chloride, sulfate, carbonate and hydrogen carbonate interfere with the determination, and depending on the column also other ions. Metals — e.g. barium and silver ions released during sample pretreatment — bind to the column packing; they are eliminated with a metal clean-up column or special exchangers. Solids and organic compounds (mineral oils, detergents, humic acids) shorten the lifetime of the columns; the effect of the organic acids checked was found not to be significant (Annex E).

REAGENTS AND SOLUTIONS (clause 6). Water of grade 1 according to ISO 3696. Bromate stock solution 1000 mg/l BrO₃⁻: 1.306 g of potassium bromate dried for at least 1 h at (105 ± 5) °C is dissolved in a 1000 ml volumetric flask, stored at 2–6 °C and renewed every 12 months (alternatively a commercial solution). Standard solutions: I — 100 mg/l (renewed every 6 months), II — 1 mg/l (every 3 months). There are 5–10 calibration solutions, prepared on the day of use, e.g. for the range 0.5–5.0 µg/l from solution II. Two eluents are used: a separation eluent (lower concentration) and a flushing eluent (higher — removes strongly retained ions); the eluents are degassed, stored in the dark and renewed every 3 days, and their composition is chosen for the column and detector.

FORMATION AND REGULATIONS. Bromate may form during ozonation of water containing bromide — in a direct reaction of ozone with bromide or via radicals; IARC has classified it in group 2B as possibly carcinogenic (textbook “Chemia wody” [Water chemistry], Wrocław University of Science and Technology 2024, section 5.6). The parametric value for bromate in water intended for human consumption is 10 µg/l (Regulation of the Minister of Health of 22 May 2026, Dz.U. 2026 item 748, Annex 1 part B item 11); the method must have a limit of quantification of no more than 30 % of the parametric value and a measurement uncertainty of no more than 40 % (Annex 4 part B). The regulation applies from 24.06.2026; the previous regulation of 7.12.2017 (Dz.U. 2017 item 2294) ceased to have effect on that day.

WHAT WE DO NOT GIVE HERE. The publicly available text of the standard ends with clause 8 (quality requirements for the separator column). Sampling and sample pretreatment (clause 9 — removal of ozone, cartridges), the procedure with preconcentration (clause 10), the calculation of the result, examples of eluents and regeneration solutions (Annexes A, B), an example configuration with preconcentration (Annex C) and the interlaboratory trial (Annex D) are outside it — which is why we do not give the composition of eluents, sample volumes, retention times, limits of detection or precision data.

Method principle

Bromate is separated from the other anions on an anion exchanger by ion chromatography and measured with a conductivity detector with chemical suppression. Before the measurement ozone and solids are removed from the sample, and the content of chloride, sulfate, carbonate and metals is reduced on cartridges with cation exchangers. At low concentrations bromate is preconcentrated on a concentrator column, and the concentration is determined from the calibration function of the overall procedure (ISO 8466-1 or ISO 8466-2); the UV detector serves only to confirm the result.

Applications

• Water intended for human consumption — parametric value for bromate 10 µg/l (Dz.U. 2026 item 748, Annex 1 part B item 11)
• Raw, surface and partially treated water (clause 1)
• Swimming pool water (clause 1)
• Ozonated water — bromate forms during ozonation of water containing bromide (textbook “Chemia wody”, Wrocław University of Science and Technology 2024, section 5.6)

Key parameters

Standard

Standard number

PN-EN ISO 15061:2003

Title (PL)

Jakość wody — Oznaczanie bromianów rozpuszczonych — Metoda chromatografii jonowej

Title (EN)

Water quality — Determination of dissolved bromate — Method by liquid chromatography of ions

Step-by-step procedure

1. Sampling

   Take the sample according to ISO 5667-1, ISO 5667-2 and ISO 5667-3 (normative references); preservation and storage are described in clause 9, which is outside the available text of the standard.

2. Sample pretreatment

   Remove ozone and solids, and reduce chloride, sulfate, carbonate, hydrogen carbonate and metals on cartridges with cation exchangers; remove metals released from the cartridges with a metal clean-up column (3.3, 4.1, 7.2).

3. Eluents

   Prepare a separation eluent (lower concentration) and a flushing eluent (higher concentration) suitable for the column and detector; degas them, avoid renewed air pick-up (e.g. by helium sparging), store them in the dark and renew every 3 days (6.10).

4. Calibration

   On the day of use prepare 5–10 calibration solutions distributed evenly over the working range — e.g. 0.5–5.0 µg/l from standard solution II — and establish the calibration function of the overall procedure according to ISO 8466-1 or ISO 8466-2 (4.6, 6.13).

5. Resolution check

   In the chromatograms of samples and standard solutions check that the resolution between the bromate peak and the nearest peak (usually chloride) is at least 1.3: R = 2(tR2 − tR1)/(w1 + w2) (clause 8).

6. Measurement

   Introduce the sample onto the separator column directly or, at low concentrations, via the concentrator column (recovery 80–120 %); measure with the conductivity detector with suppression, and if necessary confirm the result with the UV detector (4.2–4.4, clause 5).

7. Column flushing

   Remove strongly retained ions (e.g. nitrate, phosphate, sulfate) from the column with the higher-concentration flushing eluent (4.5, 6.10.2).

8. Quality control

   Check the validity of the calibration function; if necessary carry out replicate determinations, and with matrix interferences use the method of standard addition (clause 5).

Required equipment and apparatus

Reagents, media and consumables

Health and safety (OHS)

• Potassium bromate — harmonised CLP classification: H271 (may cause fire or explosion; strong oxidiser), H301 (toxic if swallowed), H350 (may cause cancer)
• The acids and ethylenediamine listed in clause 6 of the standard are handled according to their safety data sheets
• Sodium carbonate — harmonised CLP classification: H319 (causes serious eye irritation)

Frequently asked questions