(SOPs): GC/MS ANALYSES AND DATA PROCESSING METHODS

STANDARD OPERATING PROCEDURES (SOPs):
GC/MS ANALYSES AND DATA PROCESSING METHODS FOR
ORGANOCHLORINE CONTAMINANTS IN TRADITIONAL FOODS
Analyte list
1. Select the contaminants to measure in traditional foods. Suggested compounds:
1.1. Chlordanes: alpha-chlordane, gamma-chlordane, cis-nonachlor, trans-nonachlor and nonachlor
III
1.2. DDT compounds: p,p'-DDT, p,p'-DDE and p,p'-DDD
1.3. PCB congeners: 18, 28, 44, 52, 66, 101, 105, 118, 128, 138, 153, 170, 180, 187, 195, 206 and
209
1.4. Hexachlorobenzene
1.5. Toxaphenes: 2 congeners, an octachlorotoxaphene and a nonachlorotoxaphene
GC/MS Instrumental Analyses
2. Select the instrument settings and conditions for gas chromatography/mass spectrometry in order to
measure the analytes selected above.
GC/MS settings:
injection volume
injection type
GC inlet temperature
inlet purged time
carrier gas
constant head pressure
septum purge flow
split vent flow
column dimensions
column phase
detector temperature
3-µL
splitless
270° C
1 min.
Helium
40 psi
1 mL/min.
50 mL/min.
60 mm long x 0.25 mm internal diameter
0.25 µm film-thickness "DB-5"
300° C
GC oven temperature program:
80° C for 1 min.
80° C to 150° C at 10° C/min.
150° C to 190° C at 0.5° C/min.
190° C to 315° C at 3° C/min.
315° C for 15 min.

MS selected-ion monitoring:
Approximate
Time range (min.)
Dwell
Window
Mass Time Analyte or Internal Standard
1 24-31 207 1000 Tetrachloro-meta-xylene (GC Internal
Standard
2 31-37 284 1000 Hexachlorobenzene
3 37-55 256 1000 PCB 18 and 28
4 55-65 292 1000 PCB 44 and 52
5 65-68 326 1000 PCB 103 (Internal Standard)
6 68-71 115 1000 Oxychlordane
7 71-75 292 1000 PCB 66
8 75-78 373 1000 gamma-chlordane
9 78-87 326 333 PCB 101
409 333 nonachlor III and trans-nonachlor
373 333 alpha-chlordane
10 87-92 246 1000 p,p'-DDE
11 92-97 329 1000 octachlorotoxaphene
12 97-99.6 326 1000 PCB 118
13 99.6-103 409 500 cis-nonachlor
235 500 p,p'-DDD
14 103-107 360 500 PCB 153
326 500 PCB 105
15 107-110 235 500 p,p'-DDT
360 500 PCB 138
16 110-116 394 333 PCB 187
327 333 nonachlorotoxaphene
360 333 PCB 128
17 116-122 394 500 PCB 180
430 500 PCB 170
18 122-126 430 1000 PCB 195
19 126-129 464 1000 PCB 206
20 129-132 498 1000 PCB 209
1. Adjust the Time ranges as necessary (e.g., after GC maintenance) based on the retention times of
the analytes.
2. Analyze sets of samples along with five or more calibration standards (referred to as multi-level
standards)
2.1. Each multilevel calibration standard contains the analytes at a different concentration so that the
concentrations of the calibration standards span the range of analyte concentrations expected to
be found in the tissue samples.
2.2. Monitor the GC/MS reproducibility using the mid-level calibration standard. Analyze a mid-level
calibration standard at the beginning, middle and end of the series of samples and standards.
Data Processing
3. Calculate the concentrations of the analytes relative to the Internal Standard in the samples using the
quadratic regression of signal versus concentration in the multilevel standards. [Note that this
calibration/calculation process will have its own SOP once the analysis has been validated and the
August 17, 2000 2

calculation databases have been developed.]
4. Calculate the lower quantitation limits for analytes in samples using the GC/MS minimum area
equivalent to the area of the analytes in the lowest level calibration standard analyzed with the set.
5. Calculate the % recovery of the Internal Standard PCB 103 using the GC Internal Standard
Tetrachloro-meta-xylene.
6. Calculate the estimated concentration of total PCBs by multiplying 2 times the sum of the
concentrations of the 17 PCB congeners.
- DRAFT -
August 17, 2000 3