National Human Exposure Assessment Survey (NHEXAS) Arizona Study Quality Systems and Implementation Plan for Human Exposure Assessment Standard Operating Procedure SOP-BCO-L-10.0 Procedure for Cleaning Glassware to be Used for Inorganic Metals Analysis


vvEPA
United States
Environmental Protection Agency
OS3
Office of
Research arid Development
National Human Exposure Assessment Survey
(NHEXAS)
Arizona Study
Quality Systems and Implementation Plan
for Human Exposure Assessment
Title: Procedure for Cleaning Glassware to be Used for Inorganic
Metals Analysis
Source: The University of Arizona
Notice: The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development (ORD), partially funded
and collaborated in the research described here. This protocol is part of the Quality Systems Implementation Plan (QSIP)
that was reviewed by the EPA and approved for use in this demonstration/scoping study. Mention of trade names or
commercial products does not constitute endorsement or recommendation by EPA for use.
The University of Arizona
Tucson, Arizona 85721
Cooperative Agreement CR 821560
Standard Operating Procedure
SOP-BCO-L-10.0
U.S. Environmental Protection Agency
Office of Research and Development
Human Exposure & Atmospheric Sciences Division
Human Exposure Research Branch

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Procedure for Cleaning Glassware to be
Used for Inorganic Metals Analysis
1.0 Purpose and Applicability
This standard operating procedure (SOP) describes the general procedures to be followed
for cleaning glassware used in preparing and analyzing soil, house dust, air filter, surface
wipe, or dermal wash samples for inorganic metals.
2.0 Definitions
2.1 Method Blank: all reagents (and a blank filter or wipe when appropriate) carried
through the same digestion procedure as the samples, including filtration and any
subsequent dilution.
2.2 Zero Standard: a solution acidified similarly to the digested samples and other
calibration solutions. This solution is not spiked with any analytes, nor digested.
3.0 References
3.1 "Standard Practices for Apparatus, Reagents, and Safety Precautions for Chemical
Analysis of Metals," Standard E 50, American Society for Testing and Materials,
Annual Book of ASTM Standards, Vol. 3.05, 1990.
3.2 "Standard Specification for Reagent Water," Standard D 1193, American Society
for Testing and Materials, Annual Book of ASTM Standards, Vol. 11.01, 11.03,
1991.
3.3 "Standard Practice for Total Digestion of Sediment Samples for Chemical
Analysis of Various Metals," Standard D 4698, American Society for Testing and
Materials, Annual Book of ASTM Standards, Vol. 11.02, 1992.
3.4 " Standard Practice for Measurement of Metals in Workplace Atmosphere by
Atomic Absorption Spectrophotometry," Standard D 4185, American Society for
Testing and Materials, Annual Book of ASTM Standards, Vol. 11.03, 1990.

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4.0 Discussion
This method is a nitric acid leaching procedure designed to remove all inorganic
contaminants from glassware used for metals analyses. Preparation of both the detergent
and acid baths is described.
5.0 Responsibilities
5.1	The inorganic sample preparation technician is responsible for the cleaning and
subsequent storage of glassware to be used for any inorganic analytical
procedures.
5.2	The inorganic sample preparation technician is responsible for the preparation and
maintenance of both the detergent and acid baths, and recording pertinent
information in the acid bath record book.
6.0 Materials and Equipment
6.1 Materials
6.1.1	Drying convection drying oven, ~5 ft3 capacity, 30-120 °C range.
6.1.2	Cotton or synthetic towels.
6.1.3	Alconox powder detergent.
6.1.4	Acid resistant Neoprene rubber gloves (elbow-length).
6.1.5	Rectangular tanks, heavy-duty Nalgene, 18" x 18" x 12", 11 gallon
capacity, complete with cover.
6.1.6	Analytical balance, capable of weighing to 0.1 g.
6.1.7	Kimwipes (or equivalent).
6.1.8	Graduated cylinder, 1 L.
6.1.9	Fume hood.
6.1.10	Plastic-bristled brush.

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6.2 Reagents
6.2.1	Concentrated nitric acid (HN03), reagent grade
6.2.2	ASTM Type II water (ASTM D 1193)
6.2.3	Methanol, GR
Procedures
7.1	Safety
7.1.1	Nitric acid fumes are noxious and highly corrosive - use care when
pouring acid into water.
7.1.2	Avoid inhaling any particulate when pouring the Alconox into the
detergent bath.
7.1.3	Wear safety glasses and a laboratory coat at all times.
7.1.4	Wear elbow-length acid-resistant Neoprene gloves when submerging into,
or removing glassware from, the acid bath.
7.2	Preparation of Detergent Bath
7.2.1	Prepare a 7.5 g/L Alconox solution. Example:
7.2.1.1	Using a graduated cylinder, add 20 L of Type II ASTM water to
an 11-gallon Nalgene tank.
7.2.1.2	Using a balance, weigh out 150 g of Alconox powder.
7.2.1.3	With stirring, slowly add the Alconox powder to the water in the
tub.
7.2.1.4	Gently stir so as to avoid foaming, until all the Alconox is
dissolved. Replace the cover.
7.2.2	Prepare a fresh detergent bath at least once every six months.

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7.3	Preparation of Acid Bath
7.3.1	Prepare a 25% (v/v) HN03 solution. Example:
7.3.1.1	Using a graduated cylinder, add 5 L of Type IIASTM water to a
11-gallon Nalgene tank.
7.3.1.2	Move tub inside a fume hood.
7.3.1.3	Carefully add 5 L of concentrated nitric acid to the tank.
7.3.1.4	After fuming has stopped, relocate tub to the glassware cleaning
station.
7.3.1.5	Using a graduated cylinder, carefully add 10 L of Type II ASTM
water to the tank. Cover the tank with the shipped top and label
the tank, indicating acid content and strength.
7.3.2	Prepare a fresh acid bath at least once every six months.
7.4	Cleaning of Laboratory Glassware
7.4.1	Remove any tape from the glassware. Remove any markings using
methanol and a Kimwipe.
7.4.2	Rinse glassware with deionized water at least three times.
7.4.3	Place any glassware with visibly dirty residue on it in the detergent bath.
Otherwise skip to Step 7.4.4.
7.4.3.1	Scrub residue with plastic-bristle brush.
7.4.3.2	Rinse glassware three times with Type II ASTM water.
7.4.4	Submerge glassware in the acid bath overnight to leach out any inorganic
impurities.
7.4.5	Remove glassware from acid bath and rinse three times with Type II
ASTM water.
7.4.6	Place the glassware upside down on a clean surface, cover it with a clean
cotton or synthetic towel to prevent contamination, and allow to air dry.

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7.4.7	Glassware may be dried in a convection drying oven at 90 °C. Care
should be taken to avoid contamination from the metal surfaces in the
oven.
7.4.8	Once the glassware is dry (and cool, if dried in an oven), place stoppers in
the glassware, if appropriate, and then use for analysis or store at room
temperature. Store beakers upside down.
7.5 Quality Control
7.5.1	The acid bath must be re-prepared if anything metallic, e.g., a spatula, is
dropped into it.
7.5.2	If zero standards and/or method blank results have uncharacteristically
high metals concentrations, an aliquot will be taken from the acid bath and
analyzed. If the results show that the acid bath is contaminated, the bath
must be re-prepared.
Records
8.1	Records of glassware detergent and acid bath maintenance will be recorded in the
acid bath record book.
8.2	Electrical resistivity (megohms-cm, 25°C) of all Type II water stations will be
recorded with daily use in the deionised water stations.

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