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Mercury
Work Group
Other Reports >> RFP Guidelines
For more
information, contact David Eppstein by email at
deppstein@masco.harvard.edu,
or by calling 617-632-2860.
ARCI 245.1
MERCURY IN LIQUID
Revised 12/1996 245.1-2
1.0 SCOPE AND APPLICATION:
1.1 Method 245.1 is a cold vapor atomic absorption procedure approved for determining
the concentration of mercury (organic and inorganic) in mobility- procedure extracts,
aqueous wastes, and ground waters. All samples must be subject to the appropriate
dissolution step prior to analysis.
2.0 SUMMARY OF METHOD:
2.1 Prior to analysis, the liquid sample must be prepared according to the procedure
discussed in this method.
2.2 Method 245.1, a cold vapor atomic absorption technique, is based on the absorption
of radiation at 245 nm by mercury vapor. The mercury is reduced to the elemental state and
aerated from solution in a closed system. The mercury vapor passes through a cell
positioned in the light path of an atomic absorption spectrophotometer. Absorbance (peak
height) is measured as a function of mercury concentration.
2.3 The typical detection limit for the instrument used is 0.0002mg/L. TCLP analysis
detection limits for this method are 0.002mg/L.
3.0 INTERFERENCES:
3.1 Potassium permanganate is added to eliminate possible interferences from sulfide.
3.2 Copper has also been reported to interfere; however, copper concentrations as high
10mg/L had no effect on recovery, of mercury from spiked samples.
4.0 APPARATUS AND MATERIALS
4.1 Mercury Analyzer, Perkin Elmer, FIMS (Flow Injection Mercury System): A single beam
atomic-absorption spectrometer with integral flow injection sample-delivery system.
4.2 BOD bottles: 300ml BOD bottles rinsed with concentrated sulfuric acid and reagent
grade water.
4.3 Water Bath: Water Bath capable of reaching 95 degrees Celsius.
5.0 REAGENTS:
5.1 ASTM Type II water (ASTD D1193): Water should be monitored for impurities.
5.2 Sulfuric Acid: Concentrated, Reagent Grade.
5.3 Nitric Acid: Concentrated, Reagent Grade of low mercury content.
5.4 Hydrochloric Acid: Concentrated, Reagent Grade.
5.6 3% Hydrochloric Acid: Add 30m/L concentrated Hydrochloric Acid to 500m/L of reagent
grade water, dilute to 1 L.
5.7 1.1% Stannous Chloride in 3% Hydrochloric Acid: Dissolve 11 grams of Stannous
Chloride in 500ml of reagent grade water, Add 30ml of Hydrochloric acid to the solution
and dilute to 1L with reagent grade water.
5.8 Sodium Chloride-Hydroxylamine Hydrochloride Solution: Dissolve 60grams of NaCI and
60grams of Hydroxylamine hydrochloride in 400ml of reagent grade water, dilute to 500ml.
5.9 Potassium Permanganate: Dissolve 50grams of Potassium Permanganate in 900ml of
reagent grade water, dilute to 1L.
5.10 Potassium Persulfate: Dissolve 50grams of potassium persulfate in 900ml of reagent
grade water, dilute to I L.
5.11 Stock Mercury Standard: 1000ppm standard purchased.
5.12 Mercury Working Standard: Make successive dilutions of the stock mercury standard
to obtain a working standard containing 0.1 g/ml with a total volume of 1Liter. The
working standard is to be prepared daily.
6.0 SAMPLE PRESERVATION, AND HANDLING
6.1 Aqueous samples must be acidified to a pH<2 with HNO3. The suggested maximum
holding time for these samples is 38 days in glass containers and 13 days in plastic
containers.
6.2 Nonaqueous samples shall be refrigerated, when possible, and analyzed as soon as
possible.
7.0 PROCEDURE
7.1 STANDARD PREPARATION: Prepare standard curve using the working mercury
standard by transferring 0.0, 0.4, 1.0, 2.5, and 5.0 ml of standard into four BOD bottles.
Bring bottles up to volume (100mL) with reagent grade water. Add to each bottle 8mL of 2:1
sulfuric-nitric acid, and 15 mL of potassium permanganate to each and let stand for 15
minutes. If purple color remains constant for 15 minutes, add 8mL of potassium persulfate
to each bottle and heat for 2 hours in a water bath maintained at 95 degrees C. After 2
hours, remove the sample bottles from the water bath and allow them to cool. When they
have cooled, add 6mL of hydroxylamine hydrochloride to each bottle and swirl until
solution is decolorized. Prepare along with each run, a continuing calibration standard
consisting of 2.0 mL of working standard from a different stock source as the curve. Every
10 samples analyzed is also to be accompanied by matrix spike, and spike
duplicate with the familiar matrix. These samples are to be prepared using the same
standard source as the ccv standards.
7.2 SAMPLE PREPARATION: Transfer 100mL of sample or an aliquot diluted to 100mL
to a 300mL BOD bottle. Add 8 mL of 2:1 sulfuric-nitric acid and swirl sample to mix. Add
15mL of potassium permanganate to each sample and allow to sit for 15 minutes. Sewage
samples may require additional potassium permanganate. Ensure that the same amounts of
potassium permanganate are added to standards and blanks, as all samples should receive
the same amount of potassium permanganate until the purple color persists. Add 8mL of
potassium persulfate and swirl sample bottles to mix. Samples should then be heated in a
water bath for 2 minutes at 95 degrees Celsius. After 2 hours remove the samples from the
water bath and allow to cool. When cool, add 6mL of hydroxylamine hydrochloride and swirl
until the solution has decolorized.
7.3 ANALYSIS: All samples and standards are to be read using the FIMS system.
After allowing the FIMS to warm up (energy level > 40) analyze the standard calibration
curve obtaining a graph of the curve. Read the CCV and depending on the percent recovery
of the standard (80%-120%) accept the curve or rerun the curve if not within accepted
parameters. Analyze samples, recording results in ug/L and converting to mg/L if needed.
Detection limits for non-diluted samples is 0.0002mg/L. Detection Limits for TCLP metals
is 0.002mg/L.
8.0 QUALITY CONTROL
8.1 Calibration Curves: Calibration curves are to be composed of a minimum of four
standards as well as a method blank. All calibration curves are to be printed out and
saved in the mercury data binder. Calibration is checked for every run through the use of
the check standard analysis with the frequency 15%. If percent recovery for ICV is out of
20% range, rerun the calibration standards and remake the check standards from an
independent preparation stock standard.
8.2 Dilution: Samples that are higher than the highest sample used to calibrate the
instrument must be diluted and rerun with results falling into the range of the curve
standards.
8.3 Blanks: One method blank is to be run with every batch of mercury samples analyzed
to determine if contamination or any memory effects are occurring.
8.4 Matrix Spikes: Matrix spikes and spike dupes are to be run every I0 samples.
Recovery range should not exceed 20%.
11.0 REFERENCES
11.1 Methods for Chemical Analysis of Water and Wastes, EPA-600/4-82- 055, December
1982, Method 245.1.
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