StayClean™ Ion Source QSight LC-MS/MS for Quantitation of Microcystins and Nodularin in Drinking Water According to EPA Method 544

Drinking Water
Oral Presentation

Prepared by S. CAI1, J. Wu2, T. Hey3, A. Payne1, N. Kennedy1
1 - PerkinElmer, 710 Bridgeport Ave, Shelton, CT, 06484, United States
2 - PerkinElmer Canada, Inc., Jingcun Wu, 501 Rowntree Dairy Rd, # 6, Woodbridge, ON, L4L 8H1, Canada
3 - PerkinElmer Canada, Inc., 501 Rowntree Dairy Rd, # 6, Woodbridge, ON, L4L 8H1, Canada


Contact Information: [email protected]; 951-258-2470

ABSTRACT

Cyanobacteria, also known as blue-green algae, can produce cyanotoxins known as microcystins and nodularins. Cyanobacteria are found in surface waters such as lakes, streams, and ponds and when conditions are favorable, cyanobacteria can bloom and release cyanotoxins into the water. Blooms caused by cyanobacteria can be harmful to the human health, animals, and the environment. Molecular tests are available to determine if cyanobacteria carry the toxin gene but quantitative analysis, such as liquid chromatography tandem mass spectrometry (LC-MS/MS), is required to determine if cyanobacteria are producing cyanotoxins. EPA Method 544 uses solid phase extraction (SPE) LC-MS/MS for quantitation of six intracellular and extracellular microcystins and nodularin in 500 mL drinking water samples (microcystin-LA, microcystin-LF, microcystin-LR, microcystin-LY, microcystin-RR, microcystin-YR, nodularin-R). This study outlines an LC-MS/MS method for the analysis of microcystins and nodularin in drinking water samples as outlined in EPA Method 544 using a PerkinElmer QSight LX50 ultra-high performance liquid chromatography (UHPLC) system along with a PerkinElmer QSight 200 series triple quadrupole mass spectrometer. Our LC method allows for a 13-minute reduction in runtime compared to the suggested LC method in EPA Method 544. The determined MRLs, ranging from 16-80 ng/L, for all analytes, are well below the US EPA guidelines and WHO guidelines for the maximum levels of microcystins in drinking water. The method showed good accuracy with all recoveries within 70-130% and good precision with all RSD below 30%. The field sample analysis showed the two field drinking water samples analyzed were below the MRL for this method.