Lab Matters Fall 2023 | Page 43

APHL 2023 POSTER ABSTRACTS results show enhanced elution of compounds , yielding increased analyte recoveries and reduced carryover . The extractor ’ s controlled flow rate diminished human error and improved reproducibility of results . We further adapted the SPE-03 to EPA method 525.2 for semi-volatile organic compounds , further extending the extractor ’ s utility and versatility . Adoption of the SPE-03 could benefit other laboratories working to meet the testing demands of the PFAS contamination crisis .

Presenter : Maggie Wills , mawills1124 @ gmail . com

Improvements to Sensitive Pesticide Detection in Produce via Gas Chromatography-Tandem Mass Spectrometry ( GC- MS / MS ) using Analyte Protectants

J . Dickie , A . Lehner , J . Buchweitz ; Michigan State University Veterinary Diagnostic Laboratory

Pesticides play a beneficial role in agricultural production , but these chemicals can be toxic when ingested by non-target organisms in high concentrations . Because ready-to-eat commodities like fresh fruit and vegetables may retain residual amounts of pesticides , government agencies regulate the use of these compounds by establishing commodity-specific tolerances . In this study , pesticide residues were extracted from produce using the QuEChERS technique ( Quick , Easy , Cheap , Effective , Rugged , Safe ). Multiple Reaction Monitoring ( MRM ) methodologies were used to effectively scan and differentiate fifteen synthetic pyrethroid residues . Initially , chromatography performance worsened with decreasing standard concentrations ; gradual shifting in Retention Time ( RT ) and skewing of peak shapes were observed and hindered ease of quantitation . To address this issue , the concept of Analyte Protectants ( APs ) was applied , where a mixture of four compounds were introduced to pesticide standards prior to each injection onto the GC column . APs are known to transiently bind to column active sites that otherwise retard or distort the chromatography . Limits of Detection ( LOD ) and Limits of Quantitation ( LOQ ) for individual compounds improved by at least an order of magnitude with standard curves [ ranging 20 to 50,000 ppb ( ng / mL )] that yielded an average coefficient of determination , R2 = 0.99 . The extended application of APs to other pesticide classes , including organophosphate and organochlorine compounds , will be presented . A survey of pesticide content in local , Michigan-grown produce will also be conducted ; public policies and resources , including the Code of Federal Regulations ( CFR ), will be used to contextualize the findings .

Presenter : Julia Dickie , juliamdickie @ gmail . com

Microbial Source Tracking for Detecting Human and Nonhuman Fecal Contamination in Drinking and Surface Waters

D . Wright-Foulkes , S . Chmura , T . Hattenrath ; New York State Department of Health , Wadsworth Center

Fecal contamination of recreational and drinking waters by human and non-human sources is of significant concern for the safety of communities . Potential sources of contamination include raw sewage , urban stormwater runoff , wastewater effluents , fertilizer usage , or domestic farm animals and wildlife . Consumption of contaminated water containing pathogenic microbes can lead to outbreaks of severe illness . Microbial Source Tracking ( MST ) methods present solutions to determine sources of fecal contamination which can assist public health officials with monitoring and remediation . This research project was designed to launch an MST program in the New York State Department of Health ( NYS DOH ) Laboratory of Environmental Biology ( LEB ) utilizing EPA Method 1696.1 : Characterization of Human Fecal Pollution in Water by HF183 / BacR287 TaqMan ® Quantitative Polymerase Chain Reaction ( qPCR ) Assay . Laboratory standard operating procedures ( SOPs ) were created , a laboratory quality assurance program was developed , and the assays were validated for reliability and performance . Amplification efficiencies , limits of detection , and reproducibility were determined using DNA reference material . Additionally , to improve detection capabilities , various sample volumes were analyzed , and two qPCR thermocyclers were used , QuantStudio 5 and 7500 Fast ( Applied Biosystems , MA , USA ), to determine the comparability of the assays across different platforms . A validation package will be submitted to the New York State Environmental Laboratory Approval Program ( ELAP ) for accreditation consideration . The second aim of this project was to develop assays to detect non-human sources of fecal pollution ( i . e ., ruminants and wildlife ) to provide additional information to public health officials . Literature was reviewed for non-human targets that could determine if animals from agricultural communities or wildlife native to NYS played a role in the contamination . The data gained from this part of the project will determine other potentially abundant sources of pollution , which could help determine steps for remediation .

Presenter : Dorothy Foulkes , dmwrigh1 @ outlook . com

PFAS Detection in Drinking Water Method Development

J . F . Fennessey ; Colorado Department of Public Health and Environment

Per- and polyfluorinated Substances ( PFAS ), synthetic chemicals used throughout industry , including in numerous nonstick and water resistant products , have been linked to cancer , high cholesterol levels , weakened vaccine response in children and numerous other health problems . Despite increased public awareness of PFAS toxicity , the chemicals remain a major health threat . Since the 1950s , PFAS has contaminated virtually every living thing and ecosystem on the planet . The carbon-fluoride bonds of PFAS renders them extremely resistant to destruction , making remediation extremely difficult . Even PFAS that have been phased out are still being detected in water and blood samples . Although PFAS can ’ t be easily removed from drinking water , the types and amount can be determined through liquid Chromatography-mass spectrometry ( LCMS ). As PFAS are used in the production of Teflon , used in various laboratory materials , PFAS testing requires specialized equipment to minimize laboratory contamination . The CDPHE Laboratory purchased a custom Solid Phase Extraction instrument , EZPFC , and is awaiting the installation of the State of Colorado . There are currently two EPA drinking water methods , EPA 537.1 and EPA 533 , which will standardize our procedure and validate for use on these instruments in our laboratory . Once we are able to accurately and precisely measure PFAS in water , this method will be available for use on water samples collected across the state . We can then use the wastewater method EPA 1633 , which can detect