Samples for glyphosphate analysis are collected in 40-mL vials, leaving headspace in case of sample expansion. Volatile organic compounds are collected in 40 mL baked glass vials without headspace. Do not field rinse bottles prepared for organic-compound samples . Collect three vials per sample for ground water and four vials per sample for surface water. Do not use tape on the vials.
Tape causes the autosampler to jam.
Do not aerate the sample. Samples with air bubbles must be discarded. To determine the number of HCl drops needed to lower sample pH to 2 before collecting the sample, collect a test sample toward the end of purging and pour 40 mL of the sample into a beaker or spare VOC vial. Do not use pH indicator strips that are old or expired. If the vial was supplied with chemical treatment, do not fill vial to overflowing.