Analyzing anions in environmental samples

Municipalities and industries alike analyze unwanted anions in drinking, waste, and environmental waters to keep water safe and to comply with national and local regulatory agencies. These anions include:

For more than 20 years, Thermo Fisher Scientific has been working with U.S. EPA, ASTM, ISO, and other regulatory agencies in anion method development. The environmental testing industry makes wide use Thermo Scientific™ Dionex™ ion chromatography (IC), IC-MS, ICP-MS, and ion-exchange columns for determination of anions in water matrices.

Importance of Common Anions Analysis

Monitoring Inorganic Anions in Waters Using Sensitive EPA Method 300.1

Common anions include fluoride, chloride, nitrate, nitrite, sulfate, bromide, sulfate, and phosphate. Some of these ions are regulated for their impact on taste and odor, whereas other ions  are hazardous to our health when present at amounts above the regulated concentration.

Key Regulatory Developments
  • U.S. water quality is legislated through the Safe Drinking Water Act (SDWA) and the Clean Water Act (CWA)
    • CWA aims to reduce the discharge of pollutants into waters
    • SDWA ensures the integrity and safety of drinking waters
  • U.S. has regulated drinking water standards for primary (e.g., fluoride, nitrite, and nitrate) and secondary (e.g., fluoride, chloride, and sulfate) inorganic anions. These inorganic anions have been sensitively monitored by ion chromatography (IC) using U.S. EPA Method 300.0 (and now EPA Method 300.1) since the mid-1980s
  • In 1992, U.S. EPA Method 300.0 has been promulgated for compliance monitoring in all U.S. EPA regions for the analysis of inorganic anions in wastewater under the National Pollution Discharge Elimination System program
  • ISO 10304-1  and ASTM D4327  are also validated for anion analysis
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Importance of Hexavalent Chromium Analysis

Working with U.S. EPA in Cr(VI) Method Development for Over
20 Years

Although Cr(III) is an essential element for humans, Cr(VI) is a highly toxic form of chromium. A contaminant often resulting from industrial use of chromium, Cr(VI) is regulated and monitored as a primary drinking water contaminant in the U.S.

Key Regulatory Developments
  • Thermo Fisher Scientific has worked with the U.S. EPA for over 20 years. We helped develop Method 218.6 and Method 218.7 for the determination of Cr (VI) in drinking water
  • We’ve also worked in conjunction with the:
    • U.S. EPA Office of Ground Water and Drinking Water
    • California Department of Environmental Protection
    • EPA Office of Solid Waste to develop Method 7199
    • California EPA Air Resources Board to develop Method 425
  • Development of the EPA 218.6 and 218.7 is based on:
  • The 2 mm column, also approved in Method 218.7, is described in details in
  • Updates to Methods 218.6 to 218.7 are described in this article published in The Column
  • Application Note 1116 describes a new, sensitive method for Cr (VI) that does not required post-column derivatization used in Methods 218.6 and 218.7
For more information

Importance of Perchlorate Analysis

U.S. EPA Regulates Perchlorate in Water; Scrutiny May Expand
into Food

Perchlorate has been found in drinking and surface waters and poses a risk to public health risk, especially children and pregnant women, due to the interference with iodide uptake in the human thyroid.

Key Regulatory Developments
  • The U.S. EPA has regulated perchlorate levels under the Safe Drinking Water Act (SDWA) in February 11, 2011
  • Several U.S. states have enacted drinking water standards for perchlorate, while other states have established non-enforceable, advisory levels for perchlorate
  • The State of California Office of Environmental Health and Hazard Assessment (OEHHA) recently set a new Public Health Goal for Perchlorate at 1 ppb
  • While not officially regulated in European countries, European and International Standardization committees have recently started working on standardizing IC methods to monitor perchlorate
  • The U.S. FDA has been examining perchlorate occurrence in food supplies, while the Centers for Disease Control (CDC) have targeted assessment of human exposure
  • Robust IC, IC-MS, IC-MS/MS, and LC-MS methods are now available for measurement of perchlorate in a variety of sample matrices

To review U.S. EPA Methods for perchlorate using suppressed conductivity
For more information 

Importance of Haloacetic Acid Analysis

U.S. EPA Regulates Five HAAs Referred to as HAA5

Haloacetic acids (HAAs) are a class of disinfectant byproducts (DBP) that can be formed during the disinfection step of processing water. They are potentially harmful to humans.

Key Regulatory Developments
  • The U.S. EPA has regulated five haloacetic acids referred to as HAA5: monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, and dibromoacetic acid
  • U.S. EPA Stage 1 Disinfectants/Disinfection Byproducts Rule  regulates the HAA5 at 60 µg/L annual average
  • U.S. EPA Methods 552.1 , 552.2  and 552.3 are presently used for analyzing the HAAs, but are labor intensive and require multiple extraction, toxic reagents, and derivatization steps
  • U.S. EPA Method 557 is a direct-injection IC-MS/MS method that has been validated for determination for nine HAAs, bromate and dalapon with greater than 90% recovery in the presence of high concentrations of matrix ions such as chloride and sulfate
  • We are currently validating a new 2D-IC method with the U.S. EPA that allows direct injection of drinking water (without the need for derivatization) and achieves the same sensitivity as the IC-MS/MS method
For more information

Importance of Bromate Analysis

Which Method is Right for You?

Bromate is a disinfection byproduct (DBP) generated from the oxidation of bromide in drinking water by ozonation. Bromate is also a known carcinogen and is regulated in many countries.

Key Regulatory Developments 
  • The U.S. EPA has established a maximum contaminant level goal (MCLG) of 0.8 µg/L and a regulatory maximum contaminant level (MCL) of 10 µg/L of bromate in drinking water
  • The Japanese Ministry of Health, Labor and Welfare has a similar regulated limit
  • The European Commission established a lower MCL of 3 μg/L bromate in natural mineral waters and spring water treated by ozonation
  • The U.S. EPA developed multiple methods for bromate analysis:
    • U.S. EPA Method 300.0 Part B uses suppressed conductivity detection
    • U.S. EPA Method 300.1 Part B (which replaces EPA Method 300.0 Part B) and ISO 15061
    • U.S. EPA Method 317.0, Method 326.0 and ISO 11206 methods using post-column reagent and absorbance detection to analyze  water samples containing high concentrations of chloride and sulfate
    • U.S. EPA Method 302.0 uses  2D-IC without post-column derivitization to analyze water samples with high concentrations of chloride and sulfate: Download Application Note 187
For more information 

Importance of Chlorate Analysis


Chlorate is a toxic disinfection byproduct (DBP) generated during water processing and therefore a public health concern.

Key Regulatory Developments
  • The U.S. EPA has listed chlorate in the contaminant candidate list 3 (CCL3) and monitored in the unregulated contaminant monitoring rule 3 (UCMR 3) for its health effects and frequency and levels of occurrence monitoring and evaluation
  • The UCMR3 requires the use of EPA Method 300.1 for chlorate monitoring
  • ASTM D6581-08  and Standard Methods 4110D (1997)  methods have also been validated for chlorate analysis
For more information 
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