Working To Keep Drinking Water Safe
Blog May 21, 2019
There’s nothing as refreshing as a nice, crystal clear glass of water. But what if that innocuous looking liquid were to be harboring harmful chemicals? Not so appealing now. Environmental testing is key in maintaining water safety and quality. Official limits are in place regarding the levels of a multitude of substances that are deemed to be safe and acceptable to ensure that standards are maintained. In order to fulfill these requirements however, analysts need the tools to enable them to do this.
We spoke to Yan Liu, Director of Chemistry R&D, and Katariina Majamaa, Senior Manager in Product Marketing, at Thermo Fisher Scientific about their new columns designed to enable rapid separations of contaminants prior to analysis using ion chromatography-mass spectrometry (IC-MS).
Karen Steward (KS): What prompted the development of this new column?
Yan Liu and Katariina Majamaa (YL & KM): Haloacetic acids (HAAs) are contaminants in drinking water formed during the water disinfection process that use chlorine or chloramine. As a result of their suspected carcinogenicity and toxicity, HAAs are regulated by the United States (U.S.) Environmental Protection Agency (EPA) as part of the Safe Drinking Water Act (SDWA), with the maximum contamination levels for five of the HAAs (HAA5: MCAA, DCAA, TCAA, MBAA and DBAA) set at 60 µg/L. EPA Method 552.2 uses gas chromatography with electron capture detection (GC-ECD) to determine HAAs after sample acidification, extraction, and derivatization. This method is time consuming and labor intensive due to the need for sample preparation and analyte derivatization. EPA Method 557 is an improved method for the determination of HAAs, bromate, and dalapon in drinking water samples. As part of this method, ion chromatography with electrospray ionization tandem mass spectrometry (IC-ESI-MS/MS) is used to analyze HAAs, bromate, and dalapon in drinking water samples directly without the need of sample preparation and analyte derivatization. Thermo Scientific Dionex IonPac AS24 columns have been used already in EPA Method 557 to successfully resolve and separate the HAAs, bromate, and dalapon from the matrix ions such as chloride, sulfate, carbonate, and nitrate. To meet the increasing demand for the faster separation of HAAs, bromate, and dalapon from the matrix ions, a new range of IC columns was developed: the Thermo Scientific Dionex IonPac AS31 columns.
KS: How do these columns compare with existing options, what makes them particularly suited to drinking water analysis?
YL & KM: We innovate chemistry within a column according to the needs of the application, such as drinking water analysis, to ensure their suitability and maximum performance. Thermo Fisher Scientific recently launched the Dionex IonPac AS31 columns that are packed with a novel anion exchange resin developed specifically for faster analysis of HAAs, bromate, and dalapon in drinking water samples. The IonPac AS31 columns have high ion exchange capacity and allow large loop injections for trace analysis (μg/L) without sample pre-treatment. The IonPac AS31 columns operates at 15°C and about 3200 psi, so work well with the Thermo Scientific Dionex ICS-5000+ or Thermo Scientific ICS-6000 High Pressure Ion Chromatography (HPIC) systems. Our research & development (R&D) team has demonstrated that IonPac AS31 columns can meet or exceed the performance requirements of EPA Method 557. The IonPac AS31 columns deliver 39 % faster run times relative to IonPac AS24 columns, reducing the EPA Method 557 run time from 57 minutes to 35 minutes. The IonPac AS31 columns have also been designed to increase the productivity and reduce operational costs for laboratories that employ EPA Method 557 for the determination of HAAs, bromate, and dalapon in drinking water samples.
KS: What might a user be looking to detect in a drinking water sample?
YL & KM: Drinking water quality is a universal health concern with global impact. Analyses of drinking water are regulated by recommendations given by regional, federal or global agencies, and water quality is monitored to ensure strict compliance with the applicable regulatory requirements. These agencies have developed standards for water analysis to assure that the community is consuming only safe drinking water. The SDWA sets legal limits on the levels of certain contaminants in drinking water. Under the SDWA, the U.S. EPA enforces the National Primary Drinking Water Regulations (NPDWRS or primary standards) that apply to all public water systems. The NPDWR mandates maximum concentration levels of certain drinking water contaminants, also called “maximum contaminant levels” or “MCLs”. The EPA also provides a list of acceptable techniques for treating drinking water to reduce regulated contaminants to acceptably low levels. In Europe, the Drinking Water Directive provides the essential quality standards for water quality. These quality standards were developed using guidelines from the World Health Organization (WHO) and the European Commission’s Scientific Advisory Committee. Contaminant levels (and therefore what users would aim to detect) in drinking water are continuously subject to reassessment by these regulatory bodies, both regarding revised levels, as well as the addition of new contaminants to the list of existing monitored substances. The SDWA alone requires testing for over 90 possible contaminants using approved analytical methods for contaminants such as inorganic anions and cations, metals, radionuclides and organic pollutants.
IC technology is used to detect ions and polar molecules based on their affinity to an ion exchanger (column). It is most commonly used to analyze inorganic anions (EPA 300.0 or EPA 300.1) and for anion analysis measuring nitrate, nitrite, fluoride, and disinfection by-products (bromate, chlorite, perchlorate, HAA) or metals, for example hexavalent chromium Cr(VI).
KS: New contaminants are emerging all the time, how do you to keep pace with the change?
YL & KM: The team at Thermo Fisher commits a significant amount of time and effort to keep pace with these changes. We collaborate and partner with regulatory agencies and standardization bodies to develop new analytical methods that are used in compliance monitoring for environmental contaminants– both current and emerging. It is essential that our product, application and method development responds to, for example, newly proposed contaminants such as the latest list of chemicals included within the U.S. EPA’s unregulated contaminant monitoring rule (UCMR). We are participating in round robin studies to ensure methods meet performance standards in any laboratory. We also update methods with our latest technology to help make these methods more cost-effective and robust so that labs are more efficient–a great example of this is the development of the new Dionex IonPac AS31 analytical column in IC-MS workflow.
KS: What drinking water contaminant would you consider to be the biggest current threat to health and the environment and what do you foresee being the biggest threat in the future?
YL & KM: As drinking water quality also has a significant local impact–the environmental and human health risk is largely dependent on the region/location, source water, distribution infrastructure and the water purification methods used (such as disinfection). The challenge is complex and therefore it’s hard to name just one or two of the biggest threats. Therefore, we will continue to be focused on R&D and method development in collaboration with regulatory bodies as well as customers to address their needs. Currently most pressing drinking water challenges are related to contaminants of human made origin: disinfection by-products, pesticides, perfluorinated compounds (PFOS, PFOA) and potentially endocrine disruptors.
Yan Liu and Katariina Majamaa were speaking to Dr Karen Steward, Science Writer for Technology Networks.