Environmental Testing Services

Total Cyanide in Drinking Water by EPA 335.4


EPA 335.4 is used to determine the concentrations of Total Cyanide in drinking water.


EPA 335.4 is performed using semi-automated colorimetry following distillation.

Holding Time

Samples have a 14-day holding time. Samples not analyzed within this period must be discarded and replaced.

Container and Preservative

Chlorinated samples must first be dechlorinated with ascorbic acid. If sulfide is present in the sample, it must be removed by treatment with lead carbonate. A sample containing aldehydes must be treated with ethylenediamine (EDA). A sample containing a high nitrate level must be treated with sulfamic acid. Following necessary pretreatments, collect the sample in a 120 mL poly bottle which contains sodium hydroxide.

Shipping/Transport Instructions

Samples must be chilled to >0°C to ≤4°C or less at the time of collection and 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
Total Cyanide 57-12-5 1.0 μg/L