Specimen Collection & Handling Flashcards

Which of the following is the BEST way to label a sample container in the field?

Answer: Use a waterproof label with a unique sample ID, date, time, sampler, preservative, and analyses

Complete, waterproof labels on each container tie the sample to field records and the chain of custody.

A field blank differs from a trip blank because the field blank is:

Answer: Opened and exposed to field conditions at the sampling location

Field blanks are poured or exposed at the site to detect contamination from ambient field conditions.

What is a key concern when collecting groundwater samples with a bailer for VOC analysis?

Answer: Aeration and agitation during bailing can cause volatile loss

Bailer insertion and pouring agitate and aerate the water, which can bias VOC concentrations low.

For a composite soil sample, which analysis is generally NOT appropriate?

Answer: Volatile organic compounds

Compositing requires mixing that releases volatiles, so VOC samples are collected as discrete grabs.

Rock hand specimens collected for petrographic thin sections should be:

Answer: Fresh, unweathered, and marked with location and orientation as needed

Fresh material shows true mineralogy and texture, and documented location and orientation preserve geologic context.

The holding time for an unpreserved water sample analyzed for nitrate is about:

Answer: 48 hours

Under 40 CFR Part 136, unpreserved nitrate samples must be analyzed within 48 hours when cooled to 6°C or below.

When decontaminating sampling equipment for organic analysis, what is a typical sequence?

Answer: Non-phosphate detergent wash, tap water rinse, solvent rinse if required, analyte-free water rinse, air dry

Standard decontamination moves from detergent scrubbing to progressively cleaner rinses, adding solvent rinses for organics as the project plan specifies.