Automated determination of major anions and oxyhalides in drinking water using OMNIS IC and single-standard calibration

Safe drinking water monitoring requires accurate determination of both major inorganic anions and regulated disinfection byproducts (DBPs) such as bromate, chlorite, and chlorate. This white paper demonstrates how OMNIS IC combines high analytical performance with advanced laboratory automation for drinking water analysis. Automated eluent production and Metrohm intelligent Partial Loop Injection Technique (MiPT) simplify calibration and routine operation while reducing manual workload and potential sources of error.

For routine analysis of major anions (i.e., fluoride, chloride, nitrite, bromide, nitrate, phosphate, and sulfate) according to EPA Method 300.0 Part A and ISO 10304-1, the Metrosep A Supp 19 provides robust separation even in challenging, high-matrix water samples. Complete separation is achieved within 20 minutes, while MiPT enables calibration over a 1:400 concentration range from a single mixed standard, delivering excellent precision, recoveries, and negligible carryover.

For laboratories that need to monitor both major anions and trace-level oxyhalide DBPs (chlorate, chlorite, bromate, and dichloroacetate (DCA)), the Metrosep A Supp 20 enables the simultaneous determination of EPA Method 300.1 Parts A and B analytes, as well as ISO 10304 Parts 1 and 4 (excluding DCA), in a single chromatographic run. Elution is completed in less than 30 minutes. The combination of high column capacity, excellent selectivity, and OMNIS IC automation provides an efficient workflow for regulatory drinking water monitoring, from routine quality control to compliant trace-level analysis.

Highlights discussed in the white paper:

• Regulatory-compliant analysis according to EPA 300.0/300.1 parts A and B and ISO 10304 parts 1 and 4
• Major anions separated in under 20 minutes with the Metrosep A Supp 19
• Major anions and trace-level DBPs determined in a single chromatographic run in under 30 minutes with the Metrosep A Supp 20
• Automated 1:400 calibration from a single mixed standard using MiPT
• Reliable results with less manual work, excellent recoveries, and negligible carryover