XAD-8 & XAD-4
Experimental Procedure
* This procedure is for extracting NOM fractions with XAD-8 resin. The procedure for XAD-4
is generally the same as XAD-8. Differences such as flow rates are noted.
Prior Procedures Needed
 XAD resin cleaning
Supplies needed
* Based on 6, ~500 ml samples
 6 - Spectrum ~50 ml, 1 cm diam. columns
 18 - 600 ml glass bottles (thoroughly washed)
 ~22 - 40 ml glass sample vials for DOC analysis (thoroughly washed)
 48 ml XAD-8 resin
 36 ml XAD-4 resin
 1 glass pipette with large opening for loading the columns. (If pipette does not fit in column,
another pipette will be needed for water removal from columns during loading)
 2L 0.1 N NaOH (8 g NaOH in 2 L MQ water)
 2L 0.1 N H3PO4 (14 ml concentrated H3PO4 in 2 L MQ water)
 MQ squirt bottle
 10 ml graduated cylinder
 timer
Apparatus
Red line = 8 ml
Blue line = 6 ml
Column
Pump
To Sample Bottle
or
Waste
Feed Sample
02/12/16
1
116103888
Tubing clamp
Air Purge Screw
Overall Procedure
* Based on recommended sample and resin volumes (see “XAD-Background”)
1) Pack column with XAD-8 resin
2) Rinse Column
3) Check DOC
4) Prepare Sample
5) Run Sample
6) Repeat for XAD-4 resin (omit Step 4, below)
Notes:
 Acidified samples do not need to be acidified if using the Sievers DOC machine.
Therefore, set the acid flow rate in the Sievers to zero for these samples.
 H3PO4 was used instead of the original HCl to accommodate for the use of the Sievers DOC
machine. The Cl- in HCL causes an oxidant demand and subsequent decrease in oxidant
available for the oxidation of the NOM.
 It is recommended that you use different colored tape to mark the raw, XAD-8 eluent and
XAD-4 eluent sample bottles to avoid confusing samples
 Columns may drain via gravity, so check their status on occasion
 On top fitting, Do NOT over tighten fitting because the glass may crack.
 On bottom fitting (shown below), All Fittings should not be adjusted during operation or
cleaning. If the valve becomes loose, Do NOT over tighten because the Teflon threads will
strip and the valve will need replacement
Do Not Loosen for
cleaning or Over Tighten
Do Not Over Tighten if loose
(Thread stripping will occur)

When turning the valve on and off, be sure to hold the valve with the other hand to prevent
over tightening of the fitting.
02/12/16
2
116103888
XAD-8
Flow rate = 1.3 – 2.0 ml/min.
Step 1 – Load Column
1) Ensure valve is turned off to prevent column from running dry.
2) Load column with resin to appropriate volume. Be aware that the resin may settle over time
(up to 0.5 ml)
3) Before screwing on top of column, make sure all resin beads are removed from threads and
lip of column. (Failure to do so will damage the threads and seal and may cause leaks)
Step 2 – MQ rinse
1) Purge air from column and rinse column with MQ overnight (~12 hours) or with at least 500
ml.
Step 3 – Acid/Base Rinse
Note: When pumps are not running (i.e. when switching rinsing solutions), it is recommended
that the column valves be shut off to prevent columns from draining by gravity. (Turn the valve
off first and then immediately turn the pump off to prevent a pressure spike)
1) Rinse column with 0.1 N NaOH for ~1-3 hours. At the end, take a sample of the feed NaOH
solution and the product. Lower the pH of theses two samples to ~7 with H3PO4 and
measure the DOC. The difference between the feed and product should be no more than a
few hundred ppb. The NaOH will cause a rise in the DOC of the feed MQ solution to ~500
ppb. While waiting for the DOC to run, complete steps 2 and 3.
2) Rinse column with ~ five column volumes (void volume + head space  4 ml) of MQ (t  25
min.)
1) Rinse with
NaOH
2) Rinse with MQ
3) Rinse with
H3PO4
To Waste
To Waste
Collect vial for
DOC measurement
To Waste
02/12/16
Collect vial for
DOC measurement
3
116103888
3) Rinse column with ~ five column volumes of 0.1 N H3PO4, phosphoric acid (t  25 min.)
4) If the differential DOC is too high, repeat the steps, re-measuring the product DOC.
5) Be sure to finish off with steps 2 and 3 before running the sample
Step 4 – Sample prep
1) Obtain at least 600 ml of  0.45 m filtered sample
Note: If sample is limited, values (i.e. XAD volume) will have to be adjusted
2) Acidify sample to pH = 1.90 – 2.00 with H3PO4, check with pH paper.
(If samples have high carbonate levels they will likely require sparging to remove the CO2
gas produced. Sparge for 5-10 minutes with He (g) passed through a glass fritted sparger)
3) Collect sample for raw water DOC and UV analysis
Step 5 – Sample run
1) Run sample through column to waste with one column volume + tubing volume to rinse out
MQ water (~6 min.). Check flow rate with graduated cylinder and timer.
2) Run sample through column according to previous calculation (see “XAD Background”)
3) Collect column effluent in 600 ml glass bottle for XAD-4 analysis.
4) Remove 2 - 40 ml samples from glass bottle at end of run for DOC and UV analysis.
1) Run 1 column
volume of sample
To Waste
2&3) Run sample
Collect effluent
XAD
Effluent
Clean Up) Rinse
Column with MQ
Collect effluent
To Waste
XAD
Effluent
8) Collect 2 vials, for DOC
and UV measurement
4) Collect 2 vials, for DOC
and UV measurement
02/12/16
6&7) Elute off
absorbed NOM
4
116103888
Note (Steps 5-8): Back elution is performed to be able to obtain UV measurements materials
attached to the resin and/or to perform a mass balance. If this info is not needed, go to clean-up.
It is possible to do this in a reverse direction, by reversing the tubing, but this often clogs the top
fitting with suspended resin.
5) Pump 0.1 NaOH at the lowest flow possible for ~1 hr (dependent on amount of absorbed
organic matter
6) Collect sample and lower the pH to ~2 with H3PO4
7) Remove 2 – 40 ml samples from glass bottle at end of run for DOC and UV analysis
Step 6 – Clean-up
1) If DOC sorbed on the resin was not eluted, run 0.1 N NaOH solution through column for 0.51 hour to remove the humic substances.
2) Run MQ through system to clear all of the sample from the tubing.
3) Remove resin from column
4) Redraw lines on column that indicate volume (red, blue, black)
5) Clamp column upside down to dry (column top removed)
6) Organize tubing
7) Replenish used supplies (MQ, acid, base)
Photo: General look of cleaned up work space and column
02/12/16
5
116103888
QA/QC:
XAD extraction of NOM can have a high variability in results due to the many steps and
variables in the process. One cause can be the entrainment of air in the column which creates
higher flow rates and decreased retention time. It is recommended that triplicate column tests be
performed on 10% of the samples to quantify the variability in results.
02/12/16
6
116103888