FIELD TECHNIQUES--Field Preparation of Containers for Aqueous Samples In Reply Refer To: December 20, 1991 Mail Stop 412 OFFICE OF WATER QUALITY TECHNICAL MEMORANDUM 92.02 Subject: FIELD TECHNIQUES--Field Preparation of Containers for Aqueous Samples The purpose of this memorandum is to provide standard operating procedures for field rinsing and use of sample containers. Please note that the Office of Water Quality (OWQ) and the National Water Quality Laboratory (NWQL) are conducting studies to determine causes of observed contamination of trace-element samples (refer to OWQ Technical Memorandum 91.10). The results of these studies may require modifications of field procedures, including preparation of sample containers. Until the need for new procedures is documented, the following protocols should be adhered to for routine field rinsing of containers used for aqueous sample solutions. CONTAINERS FOR INORGANIC CONSTITUENTS (including major, minor, and trace elements, and isotopes of carbon, nitrogen, and sulfur) PROTOCOLS 1. All containers and their caps are to be rinsed at the field site immediately prior to sample collection with the sample solution that will be analyzed from that container. A. Use deionized water for blank samples. B. Use filtered sample solution to rinse containers designated: o filtered/acidified (FA, FAM, FAB), o filtered/untreated (FU), o filtered/chilled (FC). C. Use unfiltered sample solution to rinse containers designated: o raw/acidified (RA, RAM, RAB), o raw/untreated (RU), o raw/chilled (RC). 2. Teflon bottles or acid-rinsed polyethylene bottles that are received uncapped from the laboratory are NOT to be used (field rinsing is not an acceptable method of cleaning Teflon or acid-rinsed polyethylene bottles). A. Uncapped acid-rinsed polyethylene bottles are to be discarded. B. Uncapped Teflon bottles should be returned to the laboratory. EXCEPTIONS TO PROTOCOLS FOR INORGANIC CONSTITUENTS (for situations that are not clear cut or not covered by this memorandum, project personnel should consult with their Regional Water-Quality Specialist) 1. Sample containers for tritium, hydrogen, or oxygen isotope analysis are NOT to be prerinsed. (Although not specifically related to container preparation, please note that polyseal caps--caps with conical plastic inserts--are required for tritium, hydrogen, and oxygen bottles. 2. Containers supplied by a cooperator or laboratory other than the NWQL MAY NOT REQUIRE field rinsing. These containers may have been specially precleaned and(or) contain sample preservative. Field personnel should follow the supplier's instructions. 3. Rinsing sample containers with deionized (DI) water instead of sample solution may be necessary or desirable under certain field conditions, provided that the deionized water is of a known quality that, at a minimum, conforms to the standards and guidelines specified in OWQ Technical Memorandum 92.01. Cases for which a DI water rinse may be appropriate: A. Quantity of sample is low. Sources for which sample volume may be inadequate include: unsaturated-zone water, ground water from wells completed in low-yielding sediments, or atmospheric deposition. Calculations based upon data in Appendix II, OWQ Technical Memorandum 92.01, indicate that sample dilution from residue DI rinsate would be insignificant. B. Potential exists for a positively biased analysis owing to sorption of sediments to container walls during a rinse with environmental sample solution (that contains high concentrations of suspended materials) with subsequent desorption following acidification. The OWQ currently has no data that confirm or disprove the possibility that analyte sorption produces measurable positive or negative biases. Studies that the OWQ has planned eventually should provide more definitive guidance. Project chiefs are responsible to use professional judgement and implement quality-control procedures that are appropriate to ensure the level of data accuracy required for their project. CONTAINERS FOR ORGANIC COMPOUNDS PROTOCOLS 1. For organic compounds, do NOT rinse sample containers provided by the NWQL. These containers have been prepared according to strict procedures appropriate for the designated analysis and should be filled directly with sample solution. 2. Do NOT use bottles received from the laboratory for organic analyses that are uncapped. A. Uncapped bottles should be discarded or returned to the laboratory. EXCEPTIONS TO PROTOCOLS FOR ORGANIC COMPOUNDS None. David A. Rickert Chief, Office of Water Quality Key words: field rinsing, bottle/container rinse, field techniques, deionized water, inorganic elements, isotopes, organic compounds. This memorandum does not supersede any previous Office of Water Quality Technical Memorandum. Distribution: A, B, S, FO, PO