HAA Extraction Procedure

DBP

HAA Extraction Procedure

* This procedure is for Extracting HAA’s from chlorinated water samples based on USEPA method 552.2.

Supplies needed

* Based on 1 sample (not duplicated)

Reagents

·  250 mL Diazomethane (see “Diazomethane Preparation Procedure”)

·  1 ml concentrated sulfuric acid

·  3 ml MtBE (methyl tert-butyl ether)

·  ~ 13g sodium sulfate

·  ~10 mg silica gel

·  65 mg ammonium chloride (if needed)

Equipment

·  disposable pasteur pipette (if stopping chlorination)

·  disposable pasteur pipette (per sample)

·  pipette bulb

·  5 ml glass pipette

·  pipette bulb - acid resistant

·  40 ml glass sample vial

·  1 ml glass syringe

·  250 ml glass syringe

·  2 ml volumetric flask (per sample)

·  medium weighing tray

·  GC vial & cap (per sample)

·  GC vial holder tray

·  waste beaker

·  orbital mixer

·  timer

·  red tape

·  red pen, black pen

Procedure

Note: samples can be left for up to 9 days between step 2 and 3

A) Sample transfer

1)  Mark a 40 ml vial at 30 ml’s and fill to the mark. It is recommended that you keep a permanent stock of marked 40 ml vials.

B) Sample prep

2)  Stop the chlorination process if needed by the addition of 65 mg ± ~3 mg Ammonium Chloride

3)  Add 1 ml of sulfuric acid (via glass pipette)

4)  Add 13 g ± ~0.1 g of sodium sulfate to saturate (decreases solubility of ether in water & increases partitioning)

5)  Add 3 ml of MtBE (via bottle top pipetter)

6)  Recap vials, mix on orbital mixer until all salts are dissolved (about 20 sec. w/ a vortex)

7)  Let stand for ~15 minutes (for separation).

C) Extraction

8)  Remove exactly 2 ml of the top organic layer with a pasteur pipette and add to 2 ml volumetric flask.

9)  Place 2 ml volumetric flask w/ sample in freezer for 25-30 minutes.

10) Add 250 ml of diazomethane via the glass syringe and mix gently by inverting twice.

11) Place sample in 4oC refrigerator for 15 minutes during esterification

12) Remove sample and allow it to reach room temperature for 15 minutes.

13) Add approximately 10 mg of silica gel to sample to stop reaction (When bubbles stop forming upon the addition of silica gel, the reaction is complete)

14) Transfer ~ 2 ml of sample to GC vial and cap. Ensure that no silica gel solids transfer. Analyze as soon as possible, but may be kept in freezer for 21 days @ -11 oC.

15) Make one blank with only MtBE.

D) Clean-up

Excess diazomethane should be destroyed by the addition of silica gel to bind the diazo groups. All residual MtBE and samples should be left in the hood to evaporate. White salt crystals will be left in the waste containers following evaporation; these should be cleaned out after all MtBE has evaporated.

QA/QC:

HAA analysis can have a high variability in results due to the many steps and variables in the process. It is recommended that triplicate analyses be performed on 10% of the samples to quantify the variability in results.

08/18/01 1 DBP - HAA Extraction procedure.doc