Technical Assistance

Technical assistance resources for the Organic Chemistry Branch can be accessed below: 

Trip Blanks are a required and essential element for quality control during sampling and analysis for Volatile Organics (VOA). Trip Blanks must accompany all sample containers during sampling and shipment.

NOTE: Tap Water is not an acceptable source for volatile organics trip blanks. Trihalomethanes, chlorinated compounds and other interferents are predominant in tap water. Bottled waters may exhibit similar problems.

The following are acceptable sources of analyte-free water for trip blanks:

  • Well water with charcoal filtration

  • Bottled water that has been charcoal-filtered

  • Laboratory-grade deionized water, ASTM Type II, from a system including carbon filtration cartridges (with regular maintenance/replacement of filters). 

  • Deer Park brand spring water in clear plastic bottles (no filtration necessary). Other brands of spring water may also be acceptable, but have not been tested.

Trip blank water filtration apparatus.

The most reliable source of water for VOA trip blanks is well water or distilled water that has passed through an activated carbon filter. Activated carbon is used to remove chlorine and organic contaminants from water. The Central Laboratory uses well water through a wide-bore burette packed with baked, activated charcoal (approximately 1 cubic foot of charcoal should provide sufficient contact area within in the burette). The charcoal should be replaced about every three to four months. Click here for a list of the supplies needed for this filtration setup. This is not meant to be an endorsement of any one product or brand, but simply a list of the supplies used currently at the Central Laboratory.

For questions, please contact Victor Andrews, Volatile Organics Unit, at (919) 733-3908 extension 260.