Analysis of Semi-Volatile Compounds in Marine Sediment By GC
Transcript of Analysis of Semi-Volatile Compounds in Marine Sediment By GC
Analysis of Semi-Volatile Compounds in
Marine Sediment By GC/MS-MS Greg Perez
Senior Environmental Analyst
City of Tacoma Environmental Services Laboratory
History
• 1983 - EPA identified Thea Foss and Wheeler-Osgood
waterways as part of the 12-acre Commencement Bay
Superfund site.
• 2002 – 2006 426,000 cubic yards were dredged from the
waterway, at a cost of $105 million.
History
• 2007 - Ongoing monitoring begins
• The City monitors storm drains by testing the water and
sediments regularly for possible contaminants.
• This "nonpoint" source pollution comes mostly from
stormwater runoff, soapy water, oil and fertilizers which
travel from residential areas through the City's 18,000
storm drains and 500 miles of pipes.
Sediment Quality
Objectives
• Sediment Quality Objectives (SQOs) were developed as
part of the Commencement Bay Nearshore / Tideflats
Remedial Investigation / Feasibility Study.
• The SQOs were used to identify problem chemicals,
identify sources of problem chemicals, and define
problem areas during the remedial design.
Sediment Quality
Objectives
The City and the EPA found the following chemicals
polluting the sediment in the waterways:
• Phthalates
• Polyaromatic Hydrocarbons
• Phenolics
• Pesticides
• Arochlors
• Metals
Analytes - Phenolics
• Phenol
• 2-Methylphenol
• 4-Methylphenol
• 2,4-Dimethylphenol
• Pentachlorophenol
Analytes – LPAH’s
• Naphthalene
• 2-Methylnaphthalene
• Acenaphthylene
• Acenaphthene
• Fluorene
• Phenanthrene
• Anthracene
Analytes – HPAHs
• Fluoranthene
• Pyrene
• Benzo(a)Anthracene
• Chrysene
• Benzo(a)Pyrene
• Benzo(b&k)fluoranthenes
• Indeno(1,2,3-cd)pyrene
• Dibenzo(a,h)anthracene
• Benzo(g,h,i)perylene
Analytes – Phthalates
• Dimethyl Phthalate
• Diethyl phthalate
• Di-n-Butyl phthlalate
• Butylbenzylphthalate
• Bis(2-ethylhexyl)phthalate
• Di-n-octylphthalate
Analytes – Chlorinated
Aromatics
• 1,3-Dichlorobenzene
• 1,2-Dichlorobenzene
• 1,4-Dichlorobenzene
• 1,2,4-Trichlorobenzene
• Hexachlorobenzene
Analytes – Miscellaneous
• Hexachlorobutadiene
• Benzyl Alcohol
• Benzoic Acid
• Dibenzofuran
• N-nitrosodiphenylamine
Challenges
• Reporting Limits
Analyte
SQO
ug/Kg
Reporting Limit
ug/Kg
Hexachlorobenzene 22 11
Hexachlorobutadiene 11 5.5
N-Nitrosodiphenylamine 28 14
Traditional Process
• Extensive Cleanup
• Gel Permeation Chromatography
• Copper cleaning
• Alumina
• Dilution
Traditional Process
• Analysis by GC/MS
• Multiple injections
• Most samples analyzed at least twice per analyte group.
Traditional Process
• Time Intensive
• Labor intensive
• QC Issues caused by matrix interference
• Internal Standard Failures
• Surrogate Failures
• Matrix Spike Failures
A New Approach using
GC/MS-MS
• Instrument sensitivity allows
• Smaller sample size
• Less matrix effects
• More specificity
Method
• J&W DB-5 20m X 0.18 µm X 0.18 µm
• 40° for 1 min/ 23°C/min to 260° for 0 min
• Then 10°C/min to 290°C for 4 min
• Flow 1.3ml/min
• Acquisition time 17.6 minutes
Data
Analyte 2g Result 10g data
Hexachlorobutadiene 0.6 0.5
N-Nitrosodiphenylamine 8 11
Hexachlorobenzene 9 0.6
Data
Analyte 2g 10g
µg/Kg dry µg/Kg dry
Fluoranthene 940 770
Pyrene 2600 1700
Butyl benzyl phthalate 490 150
bis(2-Ethylhexyl)phthalate 1000 880
Benzo(a)anthracene 650 410
QC Recoveries – 10g
2-Fluorophenol 24.0 12.4 35.3
Phenol-d5 44.0 37.5 53.5
Nitrobenzene-d5 51.0 59.1 56.9
2-Fluorobiphenyl 63.0 70.2 69.8
2,4,6-Tribromophenol 38.5 14.8 57.8
Terphenyl-d14 98.7 99.5 123
1,4-Dichlorobenzene-d4 108 109 103
Naphthalene-d8 108 109 103
Acenaphthene-d10 114 113 108
Phenanthrene-d10 113 113 106
Chrysene-d12 74.4 75.9 57.5
Perylene-d12 28.7 27.8 17.1
QC Recoveries – 2g
2-Fluorophenol 73.2 68 57.5 46.3
Phenol-d5 51.8 90.3 44.3 55.5
Nitrobenzene-d5 70.1 111 61.9 110
2-Fluorobiphenyl 50.2 64 43.9 54.8
2,4,6-Tribromophenol 131 149 83.4 118
Terphenyl-d14 123 128 111 97.6
1,4-Dichlorobenzene-d4 98.7 80.6 99.5 86.9
Naphthalene-d8 72.3 102 74.5 73.3
Acenaphthene-d10 265 139 274 96.1
Phenanthrene-d10 380 201 408 162
Chrysene-d12 103 102 105 117
Perylene-d12 59.7 76.3 59.6 93.3
Some remaining issues
• MDL for Bis(2-ethylhexyl)phthalate & Di-n-butyl
phthalate did not meet the acceptance criteria. blank
levels close to spike level.
• Benzoic Acid extraction recoveries were very low and
erratic. MDL did not meet the acceptance criteria. MDL
< mean recovery.
Some remaining issues
• Additional calibration points could be added to the curve
to decrease the gap between MDL and MRL except for
Benzyl Alcohol and Di-n-octyl phthalate.
• MMI injection could use more optimization
Some remaining issues
• Wide range of reporting limits for project makes selection
of calibration points difficult.
• Have to balance sensitivity for non-detects to meet
reporting limits.
• Refine method optimization by selecting less sensitive
transition or collision energy for compounds requiring a
higher upper range.
Transitions Selection
Analyte Method RT
Precursor
Ion Product Ion Dwell Time
Collision
Energy
Relative
Intensity
Indeno[1,2,3-cd]pyrene 19.23 138.1 137.1 10 10 100%
Indeno[1,2,3-cd]pyrene 19.23 137.0 136.0 10 15 89%
Indeno[1,2,3-cd]pyrene 19.23 276.0 274.1 10 40 34%
Indeno[1,2,3-cd]pyrene 19.23 138.1 125.1 10 15 20%
Indeno[1,2,3-cd]pyrene 19.23 137.0 124.0 10 15 20%
Indeno[1,2,3-cd]pyrene 17.23 274.1 272.0 10 40 8%
Conclusions
The sensitivity of the MS-MS, allows us to simplify
sample prep by:
• Reducing sample size
• Minimizing the amount of extract cleanup required
• Improving extraction efficiency by increasing solvent
to sample ratio
Conclusions
• MS-MS Improves analysis by:
• Minimizing the effect of matrix in the
chromatogram
• Providing options to reduce the effect of
interfering peaks.
• Product ions add additional level of confidence in
the identification of target compounds.
Contact Information
• Greg Perez
• Leonora Litzi-Davis