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Synonym(s):
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VOCs in Water
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Requisition Form
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G-22
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Test Description
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Volatile organic compounds VOCs by GC-MS,
EPA method 524.2
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Pre-Approval Needed
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N/A
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Supplemental Information Required
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Measure and record the chlorine residual. If the chlorine residual is >5 mg/L,
additional dechlorinating agent is required. For every mg/L of chlorine above
the initial 5 mg/L add an additional 5 mg of ascorbic acid. For example: a
sample with 7 mg/L chlorine would require 35 mg (25 + 5 + 5) of ascorbic acid.
Be careful not to add too much dechlorinating agent to the sample because this
may cause interference in the analysis.
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Supplemental Form(s)
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N/A
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Performed on Specimens from (sources)
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Environmental |
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Sample/Specimen Type for Testing
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Drinking Water |
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Minimum Volume/Size Required
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Collect two vials of drinking water and two vials of reagent water for a field blank with every sample.
Glass screw-top vial equipped with a Teflon (PTFE) faced silicone septum; 40 mL
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Storage/Preservation Prior to Shipping
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- Be sure each bottle is labeled with a waterproof marker prior to sample collection. DO NOT write on labels until after all samples are collected and vials are sealed.
- Add 25 mg of ascorbic acid to an empty vial (to dechlorinate).
- Pre-spiking of sample vials is NOT permitted
- Open the tap and allow the system to flush until the water temperature stabilizes, at least 5 minutes. Turn flow down to a smooth, pencil thin stream.
- Remove cap from the bottle, tilt, and place under stream.
- Next, half fill the vial. DO NOT SHAKE.
- Next, add sufficient 6N HCl in order to achieve a pH of < 2. (HCl is used as a
preservative) ( Don’t measure the pH in the sample bottle! Verify the amount of preservative to achieve proper pH for each sample in a separate container.) - Complete filling the vial and seal.
- Mix gently for one minute. DO NOT SHAKE.
- Store samples away from any organic solvent vapors, and avoid direct sunlight or intense light.
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Transport Medium
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N/A
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Specimen Labeling
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- Label
each bottle with a water proof marker.
- Pre-printing
labels is acceptable.
- Sample
identification must match submission form.
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Shipping and Specimen Handling Requirements
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- Ship according to
Dangerous Goods Regulations, IATA, and/or CFR 49.
- Ship on ice (4°C).
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Method
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EPA 524.2
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Turn-around Time
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Samples must be
analyzed by the lab within 14 days of collection.
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Interferences/Limitations
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Avoid collecting this type of sample in
any situation where you can smell petroleum or solvent type fumes.
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| Common Causes for Rejection
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Insufficient quantity, unacceptable
specimen type or source, improper shipping conditions, expired media or
collection container, discrepancies between specimen label and submission
form, and/or incomplete or missing submission form
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Additional Information
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Collecting Field Blanks:
- A
field blank consisting of two vials is required when collecting all VOC
samples to rule out air contamination. Treat the field blank in the same
manner as the water sample.
- The
field blank is collected at the same location and time that the water sample
is collected.
- Label
the containers to indicate that it is a field blank (“FB” or “Field Blank”).
- Add
ascorbic acid to each empty vial.
- Add
laboratory grade reagent water instead of sample water. Once the container of
laboratory reagent water is opened for this field blank, it can’t be used
again.
- Add
HCl to a pH <2.
- Complete
filling the vials and seal.
- Mix
for one minute. Invert the bottle repeatedly, do not shake.
Contact the laboratory at (512) 776-7587
for currently supported analyte list.
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