Drinking Water Analysis by EPA 524.2

Summary

EPA 524.2 is used to determine the concentrations of Total Trihalomethanes (TTHMs) in drinking water. Total Trihalomethanes are volatile organic compounds listed in the National Primary Drinking Water Regulations.

Technique

EPA 524.2 is performed using gas chromatography/mass spectrometry (GC/MS).

Holding Time

When chilled, dechlorinated, and HCL-preserved, samples have a 14-day holding time. Samples not analyzed within this period must be discarded and replaced.

Container and Preservative

Collect all samples in (2) 40-mL vials which contain 25 mg of ascorbic acid. Slowly fill each vial ½ way, making sure not to flush out the dissolving ascorbic acid from the vial. Carefully add 2 drops of 1:1 HCl to each vial. Finish filling the vial to that the water "crowns" at the top of the vial. Cap the vial and invert 3 to 4 times to mix.

Shipping/Transport Instructions

Immediately chill all samples within 15 minutes of collection to at or below 4 degrees C (≤4°C) by placing the samples in a sample refrigerator or in a cooler with ice. Samples must be maintained at that temperature until analysis. Field samples that will not be received at the laboratory on the day of collection must be packaged for shipment with sufficient ice to ensure that they will be >0°C to ≤4°C upon arrival at the laboratory.

Analytes and Reporting Limits

Analytes included on our State of Michigan Drinking Water Certification are designated as such.

  Michigan Certified

  Michigan does not offer certification

  Please request additional information on test

Analyte	CAS Number	Reporting Limit	MI Cert
Bromodichloromethane	75-27-4	1.0 μg/L
Bromoform	75-25-2	1.0 μg/L
Chlorodibromomethane	124-48-1	1.0 μg/L
Chloroform	67-66-3	1.0 μg/L