Tomorrow’s quantitation with the TSQ Fortis mass spectrometer: robust, reproducible quantitation workflows of haloacetic acids, bromate, and dalapon in water according to EPA Method 557

Significance of the topic

Drinking water disinfection generates halogenated by-products that pose health risks at trace levels including haloacetic acids bromate and dalapon

Study objectives and overview

The goal was to develop and implement a robust reproducible workflow for simultaneous quantitation of nine haloacetic acids bromate and dalapon in water according to EPA Method 557 using ion chromatography coupled to a triple quadrupole mass spectrometer

Methodology

• Samples municipal tap water preserved with 100 mg/L ammonium chloride direct injection no further prep
• Ion chromatography Dionex ICS-5000+ HPIC system with Dionex IonPac AS24A column guard column and ASRS-500 suppressor KOH gradient eluent generated electrolytically at 300 uL/min with isopropanol makeup at 200 uL/min matrix diversion valve at column outlet
• Mass spectrometry Thermo Scientific TSQ Fortis triple quadrupole in negative HESI mode SRM transitions optimized static spray voltage cycle time 2.3 s Q1 Q3 resolution 0.7 Da using TraceFinder 4.1

Used instrumentation

• Dionex ICS-5000+ Hybrid HPIC system
• Dionex IonPac AS24A and AG24A guard column
• ASRS-500 electrolytically regenerated suppressor
• Thermo Scientific TSQ Fortis triple quadrupole mass spectrometer
• TraceFinder software version 4.1

Main results and discussion

Chromatographic separation resolved all analytes from common inorganic anions with clear peaks for 11 targets
Linearity exceeded R2 0.99 over 0.25 to 20 ug/L two orders of magnitude dynamic range
Limits of detection at 0.25 ug/L for all haloacetic acids bromate and dalapon
Optimal detection for trichloroacetic acid at source temperature 200 degrees C and column temperature 15 degrees C
Application to real tap water confirmed analyte levels below regulatory limits with accurate recovery

Benefits and practical applications

• No derivatization or extensive sample preparation direct injection reduces analysis time and cost
• High sensitivity selectivity and reproducibility supports routine monitoring and regulatory compliance
• Reagent-free IC with suppressor reduces source contamination and background noise

Future trends and opportunities

• Expansion of the method to additional disinfection by-products and emerging contaminants
• Automation of sample handling and online monitoring in treatment plants
• Integration with high-resolution mass spectrometry and field-deployable platforms
• Data analytics and digital workflows to enhance laboratory efficiency

Conclusion

A direct injection IC-MS/MS workflow using the Dionex ICS-5000+ and TSQ Fortis provides a robust sensitive and reproducible solution for quantifying haloacetic acids bromate and dalapon in drinking water meeting EPA Method 557 requirements routinely and efficiently

References

1. Beck JR Wijeratne N Martins C Blackburn M EPA Method 557 quantitation of haloacetic acids bromate and dalapon in drinking water using ion chromatography and tandem mass spectrometry Thermo Fisher Scientific Poster Note 64430 2016
2. U S EPA Basic information about dalapon EPA website accessed 2018
3. Pisarenko AN Anderson JL Russell ME Rapid analysis of perchlorate chlorate and bromate ions in concentrated sodium hypochlorite solutions Analytica Chimica Acta 2010 659 1-2 8 15
4. Slignsby R Saini C Pohl C Jack R Measurement of haloacetic acids in drinking water using IC MS MS method performance Presented at the Pittsburgh Conference New Orleans LA March 2008
5. U S EPA Method 557 determination of haloacetic acids bromate and dalapon in drinking water by IC ESI MS MS 2009