Annex III
C. Apparatus
Wash all glassware with detergent (Micro
Laboratory Cleaner, International Products,
PO Box 118, Trenton, NJ 08601-0118) and
rinse thoroughly with hot tap H20 followed
by distilled or de-ionized H20. Then rinse 3
times with acetone and 3 times with toluene.
Dry in hood.
Equivalent apparatus may be used except
use packed column specified.
(a) Centrifuge. Model IEC CRU-5000 or
CR6000 (International Equipment Co.).
(b) Centrifuge tubes. Glass, 50 mL capacity with Teflon-lined screw caps (Cat. No.
9212-K78, Thomas Scientific).
(c) Graduated cylinders. Glass, class A,
50 mL capacity, with ground-glass stoppers
(Kimbie 20036).
(d) Transfer pipettes. Disposable glass,
Pasteur-type.
(e) Dropping pipettes. Glass,S mL capacity (No. 13-710B, Fisher Scientific Co.).
(f) Mechanical shaker. Model S-500
shaker-in-the-round, with timer (Glas-Col
Apparatus Co., 711 Hulman St, PO Box 2128,
Terre Haute, IN 47802.).
(g) Gas chromatograph. Hewlett-Packard
Model 5710A equipped with linear 63Ni electron capture detector, Model 7131A recorder,
and 6 ft x 2 mm id silanized glass column
packed with 5% DEGS-PS on 100-120 mesh
Supelcoport (Supelco, Inc.). Pack column no
closer than 2.0 cm from injection and detector port nuts and hold packing in place with
2 cm high quality, silanized glass wool at
both ends. Install oxygen scrubber and molecular sieve dryer (No. HGC-145, Analabs,
Inc.) between carrier gas supply and column.
Condition column according to manufacturer's instructions as follows: flush column
0.5 h with carrier gas flowing at 30 mL/min
at room temperature. Then heat 1 h at 50°C.
Next, heat column to 200°C at 4°C/min
and hold at 200°C overnight. Do not connect column to detector during this conditioning process. Maintain 30 mLlmin carrier gas flow at all times during conditioning,
treatment and use. Operating conditions:
column 155°C, injector 200 °C, detector
300°C; carrier gas flow 30 mLlmin; recorder
chart speed 0.5 -1.0 cm/min. Under these
conditions and with HgCl2 column treatment procedure described below, CH3HgCI
peak appears 2-3 min after injection of
extract.
187
D. Mercuric Chloride Column Treatment
Column of 5% DEGS-PS, conditioned according to manufacturer's instructions, can
be used to determine CH3HgCI only after
treatment by HgCl2 solution. Because column
performance degrades with time, also treat
column periodically during use. Perform
appropriate HgCl2 treatment procedures
described below.
(a) Following 200°C column conditioning
and after every 2 - 3 days of analyses. If
column has just been conditioned according
to manufacturer's instructions or has been
used 2 - 3 days to analyse extracts, proceed as
follows: adjust column temperature to 200 °C
and inject 20 }lL HgCl2 treatment solution 5
times at 5-10 min intervals. Maintain 200°C
temperature overnight. Chromatogram will
contain large, broad peaks. Adjust column
temperature to 155°C next morning and
inject 20 }lL HgCl2 treatment solution 2 more
times. Large, broad chromatographic peaks
appearing at ca. 1- 2 h signal completion of
treatment process and that column is ready
for use.
(b) On day preceding analyses. If column
has been treated by procedure (a) or used
1 day at 155°C to analyse extracts, column
may be treated at end of working day for next
day's use as follows: Lower column temperature to 115°C and inject 20 }lL HgCl2 treatment solution 1 time. After large, broad peaks
appear in chromatogram (11-20h), treatment process is complete. Next working day,
increase column temperature to 155°C operating temperature. When baseline is steady,
column is ready for use.
(c) During extract analyses at 155 °C. If
column has been used at 155°C to analyse
extracts or if column performance and peak
height have degraded enough to require
HgClz treatment, inject two 20 }lL aliquots of
HgCl2 treatment solution. Large, broad peaks
will appear in chromatogram 1- 2 h after
HgCIz injection, signalling completion of
treatment process. Wait for steady baseline;
then column is ready for use.
E. Extraction of Methyl Mercuric Chloride
Perform all operations except weighing in
laboratory hood. Take empty centrifuge tube
through all steps for method blank determination. Accurately weigh 1 g homogenized
test sample into 50 mL centrifuge tube. Add
25 mL acetone; tightly cap and vigorously
C. Apparatus
Wash all glassware with detergent (Micro
Laboratory Cleaner, International Products,
PO Box 118, Trenton, NJ 08601-0118) and
rinse thoroughly with hot tap H20 followed
by distilled or de-ionized H20. Then rinse 3
times with acetone and 3 times with toluene.
Dry in hood.
Equivalent apparatus may be used except
use packed column specified.
(a) Centrifuge. Model IEC CRU-5000 or
CR6000 (International Equipment Co.).
(b) Centrifuge tubes. Glass, 50 mL capacity with Teflon-lined screw caps (Cat. No.
9212-K78, Thomas Scientific).
(c) Graduated cylinders. Glass, class A,
50 mL capacity, with ground-glass stoppers
(Kimbie 20036).
(d) Transfer pipettes. Disposable glass,
Pasteur-type.
(e) Dropping pipettes. Glass,S mL capacity (No. 13-710B, Fisher Scientific Co.).
(f) Mechanical shaker. Model S-500
shaker-in-the-round, with timer (Glas-Col
Apparatus Co., 711 Hulman St, PO Box 2128,
Terre Haute, IN 47802.).
(g) Gas chromatograph. Hewlett-Packard
Model 5710A equipped with linear 63Ni electron capture detector, Model 7131A recorder,
and 6 ft x 2 mm id silanized glass column
packed with 5% DEGS-PS on 100-120 mesh
Supelcoport (Supelco, Inc.). Pack column no
closer than 2.0 cm from injection and detector port nuts and hold packing in place with
2 cm high quality, silanized glass wool at
both ends. Install oxygen scrubber and molecular sieve dryer (No. HGC-145, Analabs,
Inc.) between carrier gas supply and column.
Condition column according to manufacturer's instructions as follows: flush column
0.5 h with carrier gas flowing at 30 mL/min
at room temperature. Then heat 1 h at 50°C.
Next, heat column to 200°C at 4°C/min
and hold at 200°C overnight. Do not connect column to detector during this conditioning process. Maintain 30 mLlmin carrier gas flow at all times during conditioning,
treatment and use. Operating conditions:
column 155°C, injector 200 °C, detector
300°C; carrier gas flow 30 mLlmin; recorder
chart speed 0.5 -1.0 cm/min. Under these
conditions and with HgCl2 column treatment procedure described below, CH3HgCI
peak appears 2-3 min after injection of
extract.
187
D. Mercuric Chloride Column Treatment
Column of 5% DEGS-PS, conditioned according to manufacturer's instructions, can
be used to determine CH3HgCI only after
treatment by HgCl2 solution. Because column
performance degrades with time, also treat
column periodically during use. Perform
appropriate HgCl2 treatment procedures
described below.
(a) Following 200°C column conditioning
and after every 2 - 3 days of analyses. If
column has just been conditioned according
to manufacturer's instructions or has been
used 2 - 3 days to analyse extracts, proceed as
follows: adjust column temperature to 200 °C
and inject 20 }lL HgCl2 treatment solution 5
times at 5-10 min intervals. Maintain 200°C
temperature overnight. Chromatogram will
contain large, broad peaks. Adjust column
temperature to 155°C next morning and
inject 20 }lL HgCl2 treatment solution 2 more
times. Large, broad chromatographic peaks
appearing at ca. 1- 2 h signal completion of
treatment process and that column is ready
for use.
(b) On day preceding analyses. If column
has been treated by procedure (a) or used
1 day at 155°C to analyse extracts, column
may be treated at end of working day for next
day's use as follows: Lower column temperature to 115°C and inject 20 }lL HgCl2 treatment solution 1 time. After large, broad peaks
appear in chromatogram (11-20h), treatment process is complete. Next working day,
increase column temperature to 155°C operating temperature. When baseline is steady,
column is ready for use.
(c) During extract analyses at 155 °C. If
column has been used at 155°C to analyse
extracts or if column performance and peak
height have degraded enough to require
HgClz treatment, inject two 20 }lL aliquots of
HgCl2 treatment solution. Large, broad peaks
will appear in chromatogram 1- 2 h after
HgCIz injection, signalling completion of
treatment process. Wait for steady baseline;
then column is ready for use.
E. Extraction of Methyl Mercuric Chloride
Perform all operations except weighing in
laboratory hood. Take empty centrifuge tube
through all steps for method blank determination. Accurately weigh 1 g homogenized
test sample into 50 mL centrifuge tube. Add
25 mL acetone; tightly cap and vigorously