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pdfLaboratory of Organic Analytical Chemistry
Wadsworth Center
New York State Department of Health
STANDARD OPERATING PROCEDURE
Analyte: Monohydroxy-Polycyclic Aromatic Hydrocarbons (OH-PAHs)
Matrix: Urine
Method: Isotope Dilution Gas Chromatography/High-Resolution Mass
Spectrometry *
*This Method was Modified Based on CDC Method No. 09-0D
Revised: July 27, 2006
As performed by:
Division of Environmental Health Sciences
Wadsworth Center
Department Health of New York State
Contact:
Dr. Shijun Lu
Phone: (518) 474-3979
E-mail: lus@wadsworth.org
Dr. Kenneth Aldous,
Director, Division of Environmental Health Sciences
Phone: (518) 473-0030
E-mail: kma01@health.state.ny.us
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
Table of Contents
1. Clinical Relevance and Summary of Test Principle
2. Safety Precautions
a. Reagent Toxicity or Carcinogenicity
b. Radioactive Hazards
c. Microbiological Hazards
d. Mechanical Hazards
e. Protective Equipment
f. Training
g. Personal Hygiene
h. Disposal of Wastes
3. Computerization, Data-System Management
a. Software and Knowledge Requirements
b. Sample Information
c. Data Maintenance
4. Procedures for Collecting, Storing, and Handling Specimens; Criteria for Specimen
Rejection
a. Sample Collection
b. Sample Handling
c. Criteria for Specimen Rejection
5. Preparation of Reagents, Calibration (Standards), Controls, and All Other Materials;
Equipment and Instrumentation
a. Reagents and Sources
(1) Reagent Preparation
(2) Standards Preparation
b. Manual Equipment (indicated equipment or equivalent)
c. Other Materials 7
d. Instrumentation (indicated equipment or equivalent) 7
(1) High Resolution Mass Spectrometer (HRMS) Configuration
(2) Mass Spectrometer Instrument Control Language (ICL) Programs
(3) Gas Chromatography (GC) Configuration and Temperature Program
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Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
6. Calibration and Calibration-Verification Procedures
a.
Mass Spectrometer
b.
Calibration Curve
c.
Calibration Verification
d.
Proficiency Testing (PT)
7. Operating Procedures; Calculations; Interpretation of Results
a.
Sample Preparation
b.
Hydrolysis
c.
Extraction
d.
Concentration
e.
Derivatization Procedure
f.
Analysis
g.
Processing of Data
h.
Replacement and Periodic Maintenance of Key Components
8. Reportable Range of Results
a.
Linearity Limits
b.
Analytical Sensitivity
c.
Accuracy
d.
Precision
9. Quality Control (QC) Procedures
a.
QC Material
b.
Urine Enrichment
c.
Dispensing
d.
Characterization of QC Materials
e.
Use of QC Samples
f.
Final Evaluation of QC Results
10. Recoveries of Method
11. Remedial Action if Calibration or QC Systems Fail to Meet Acceptable Criteria.
12. Limitations of Method; Interfering Substances and Conditions
13. Reference Ranges (Normal Values)
14. Critical-Call Results ("Panic" Values)
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Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
15. Specimen Storage and Handling During Testing
16. Alternate Methods for Performing Test and Storing Specimens if Test System Fails
17. Transfer or Referral of Specimens; Procedures for Specimen Accountability and
Tracking References
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Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
1. Clinical Relevance and Summary of Test Principle
This method is used to assess human exposure to selected polycyclic aromatic
hydrocarbons (PAHs), a class of potential human carcinogens (1, 2), by determining the
concentrations of their mono-hydroxy metabolites in urine. Common routes of
occupational exposure to PAHs may include work involving diesel fuels and coal tars
through paving and roofing as well as possible environmental exposures including
smoking, diet, smog, and forest fires.Threshold levels for carcinogenicity have not been
determined for most PAHs.
The specific analytes measured in this method are monohydroxy-polycyclic
aromatic hydrocarbons (OH-PAHs). The procedure involves enzymatic hydrolysis of urine
(to hydrolyze PAH conjugates), liquid-liquid extraction, derivatization, and analysis using
capillary gas chromatography coupled to high-resolution mass spectrometry (GC/HRMS).
This method uses isotope dilution with carbon C-13-labeled internal standards. Ions from
each analyte and each C-13-labeled internal standard are monitored, and the abundances of
each ion are measured. The ratios of these ions are used as criteria for evaluating the data.
(See Table 1 for the analytes measured in this procedure.) By evaluating the
concentrations of these analytes in urine, laboratorians can assess human exposure to the
particular PAH analyzed.
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Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
Table 1. Analytes Measured and Their Abbreviations
Parent PAH
Metabolite/Analyte
Abbreviation
1
Naphthalene
1-hydroxynaphthalene
1-nap
2
Naphthalene
2-hydroxynaphthalene
2-nap
3
Fluorene
2-hydroxyfluorene
2-fluo
4
Fluorene
3-hydroxyfluorene
3-fluo
5
Fluorene
9-hydroxyfluorene
9-fluo
6
Phenanthrene
1-hydroxyphenanthrene
1-phen
7
Phenanthrene
2-hydroxyphenanthrene
2-phen
8
Phenanthrene
3-hydroxyphenanthrene
3-phen
9
Phenanthrene
4-hydroxyphenanthrene
4-phen
10
Phenanthrene
9-hydroxyphenanthrene
9-phen
11
Fluoranthene
3-hydroxyfluoranthene
3-flran
12
Pyrene
1-hydroxypyrene
1-pyr
13
Benzo(c)phenanthrene
1-hydroxybenzo(c)phenanthrene
1-bcp
14
Benzo(c)phenanthrene
2-hydroxybenzo(c)phenanthrene
2-bcp
15
Benzo(c)phenanthrene
3-hydroxybenzo(c)phenanthrene
3-bcp
16
Chrysene
1-hydroxychrysene
1-chry
17
Chrysene
2-hydroxychrysene
2-chry
18
Chrysene
3-hydroxychrysene
3-chry
19
Chrysene
4-hydroxychrysene
4-chry
20
Chrysene
6-hydroxychrysene
6-chry
21
Benzo(a)anthracene
1-hydroxybenzo(a)anthracene
1-baa
22
Benzo(a)anthracene
3-hydroxybenzo(a)anthracene
3-baa
23
Benzo(a)anthracene
9-hydroxybenzo(a)anthracene
9-baa
24
Benzo(a)pyrene
3-hydroxybenzo(a)pyrene
3-bap
6
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
2. Safety Precautions
a. Reagent Toxicity or Carcinogenicity
Some of the reagents necessary to perform this procedure are toxic. Exercise caution
to avoid inhalation of or dermal exposure to these reagents by wearing a lab coat and
gloves.
b. Radioactive Hazards
There are no radioactive hazards associated with this procedure.
c. Microbiological Hazards
Although urine is generally regarded as less infectious than serum, the possibility of
a laboratorian being exposed to various microbiological hazards exists. Take
appropriate measures to avoid any direct contact with the specimen (see Section
2.e.). A Hepatitis B vaccination series and a baseline test for health care and
laboratory workers who may be exposed to human fluids and tissues are
recommends. Observe universal precautions.
d. Mechanical Hazards
Following standard safety practices while performing this procedure minimizes the
risk for mechanical hazards. Avoid any direct contact with the electronic
components of the mass spectrometer unless all power to the instrument has been
shut off. Only qualified technicians should perform electronic maintenance and
repair.
e. Protective Equipment
Use standard personal protective equipment when performing this procedure. This
includes wearing a lab coat, safety glasses, durable gloves (nitrile medical
examination gloves or equivalent gloves), and appropriate footwear. Process
specimens and prepare samples using a chemical fume hood.
f. Training
Anyone performing this procedure must be trained and experienced in the use of a
high-resolution mass spectrometer. Formal training by an experienced operator of
the instrument is necessary. Personnel must also read the operation manuals from
the manufacturer. Anyone involved in sample preparation must be trained in
liquid-liquid extraction and have basic chemistry laboratory skills.
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Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
g. Personal Hygiene
Follow universal precautions. Exercise special care when handling any biological
specimen. Use personal protective equipment and wash hands properly after
completing lab work.
h. Disposal of Wastes
According to Wadsworth Hazardous Chemical Waste Management, collect solvents
and reagents in appropriate containers clearly marked for waste products, and
temporarily store them in a flame-resistant cabinet. Autoclave or decontaminate
with 10 percent bleach containers, glassware, etc., that come in direct contact with
the specimens. Wash, recycle, or dispose of the glassware in an appropriate manner
according to the Wadsworth Center Safety Guidelines. Dispose of all biological
samples and diluted specimens in a biohazard autoclave bag at the end of the
analysis according to Wadsworth Center Safety Guidelines for disposal of
hazardous waste.
3. Computerization, Data-System Management
a. Software and Knowledge Requirements
Raw data are processed for qualitative and quantitative analysis using
QualBrowser®, QuanBrowser®/QuanDesk® (Thermo Electron Corporation),
respectively. Perform statistical data analyses using Statistical Analysis System
(SAS)® software (SAS Institute, Cary, NC), or Excel® (Microsoft ). Knowledge and
experience with these software packages (or their equivalent) are required to use and
maintain the data-management structure.
b. Sample Information
Electronically transfer or manually enter information pertaining to particular
specimens into the database. Data that are manually entered should include the
sample identification number, sample type, standard number, and other information
not associated with the mass spectral analysis.
c. Data Maintenance
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Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
After inputting sample and analytical data into the database, backup the database
onto a computer hard drive and/or writable compact disk (CD-R) weekly. Backup
raw data onto the CD-RW, and/or DVD-RW monthly.
4. Procedures for Collecting, Storing, and Handling Specimens; Criteria for
Specimen Rejection
a. Sample Collection
Use standard urine collection cups to collect urine specimens from donors.
Refrigerate samples as soon as possible and transfer them within 4 hours of
collection. Collect a minimum of 20 ml of urine and pour it into sterile, 30-ml
Qorpak vials with screw-cap tops. Label specimens, immediately freeze them to
-20°C, and store them in dry ice for shipping. Carefully pack vials to avoid breakage
during shipment. If long-term storage is anticipated, then store all samples at -80 °C.
b. Sample Handling
Samples and residual specimens are stored at -80 °C until needed to be thawed,
aliquoted, and analyzed.
c. Criteria for Specimen Rejection
Specimens must be frozen when delivered to the lab. The minimum volume required
is 1.0 ml. If either of these criteria is violated or contamination due to improper
collection procedures or collection devices is suspected, the specimen should be
rejected.
5. Preparation of Reagents, Calibration (Standards), Controls, and All Other
Materials; Equipment and Instrumentation
a. Reagents and Sources (see Table 2)
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Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
Table 2. Reagents and the Respective Manufacturers
Reagent
1-nap; 2-nap, 2-fluo, 3-fluo, 9- fluo,
9-phen, 1-pyr
1-phen, 2-phen, 4-phen
3-phen, 3-flran, 1-bcp, 2-bcp, 3-bcp,
1-chry, 2-chry, 3-chry, 4-chry, 1-baa,
3-baa, 3-bap
Manufactures*
Sigma Chemicals, St Louis, MO
RCT, Laramie, WY
Midwest Research Institute, National Cancer
Institute, Kansas City, MO
6-chry, PCB-61
AccuStandard,
13
C6 1-nap
CDC, synthesized in house, Atlanta, GA
13
C6 1-baa, 13C6 3-bcp, 13C6 3-chry, 13C6 Midwest Research Institute, NCI Kansas
3- flran, 13C6 1-pyr
City, MO
13
Cambridge Isotope Laboratories, Andover,
C6 3-phen, 13C6 6-chry
MA
β-Glucuronidase / arylsulfatase (Type
H-3, 98,000 Unit/ml, from Helix
Sigma Chemicals, St Louis, MO
pomatia)
N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA)
Sigma Chemicals, St Louis, MO
Toluene (Nanograde)
Mallinckrodt Baker, Inc., Paris, KY
Pentane (HPLC grad)
J.T. Baker, Philipsburg, NJ
Organic Pure Water (o.p. H2O)
Prepared in house, (Milli Q water)
n-Dedocane
ChemService, West Chester, PA 19381
Buffer Solution, (pH 5.00)
Anachemia, Rouses Point, NY
Argon
BOC Group Inc., Murray Hill, NJ
* Use an equivalent manufacturer when the manufacture noted is not available.
All OH-PAH compounds are stored at -70°C and protected with Argon.
(1). Reagent Preparation
10
Standard Operating Procedure - Hydroxy PAHs in Urine
i.
July 2006
MSTFA. Open the sealed vial containing N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA) from the vendor and place the MSTFA solution in
a clean GC sample vial. Displace the air over the MSTFA with a gentle stream
of argon. Immediately screw the cap on the vial. Store the MSTFA in the vial at
4oC could last more than 1 month.
ii.
Enzymatic-buffer Combine 250mL of buffer solution (pH=5.0, Anachemia)
and 0.6mL of β-glucuronidase / sulfatase enzyme (derived from Helix Pomatia,
98900units/ml, Sigma) in a sterilized 250ml Wheaton bottle to generate
Enzymatic-buffer (β-glucuronidase / sulfatase enzyme 300 units/ml). Store at
4oC could last more than 1 month.
(2) Standards Preparation
Due to the potential carcinogenicity of these analytes, weigh each analyte on a
microbalance inside a ventilated plexiglass box. Because all OH-PAHs are
light- sensitive, take precautions to minimize their exposure to light.
i. Stock solutions of Individual Analytes (100ng/µL). Weigh approximately 1mg
of neat OH-PAH in a screw-cap vial. Add exactly 1 mL of acetonitrile and allow
the OH-PAH material to dissolve by gently swirling it or placing it in an
ultrasonic bath. Calculate and perform the dilution to100 ng/µL for a final volume
of ~10 mL of acetonitrile. Ampoulize the individual standard solution in clean
amber ampoules, use argon to displace any air in the ampoule and seal it. Stored
at -80°C (for up to 1.5 years).
ii. Working Standard Solution of 23 OH-PAH Mix. Combine 500 µL of each
OH-PAH standard stock solutions (100 ng/µL) and 1mL acetonitrile in a 20mL
scintillant tube to generate a mixture of 23 OH-PAHs working standard solution
(each OH-PAH concentration is 4 ng/µL). Solutions of other concentrations may
also be prepared, if needed. Use argon to displace any air in the vials. Then cap
the vials tightly, place the vials in a sealed double layer plastic bag filled with
argon, and store them at -80 oC until needed (for up to 6 months).
iii. Calibration Curve Standards. Concentrations for the six points that establish
the calibration curve are 10, 50, 100, 500, 2000, 5000 and 10000 ng/L. These
11
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
standards are made from the dilution of 23 OH-PAH working standard solution
[see Section 6.c.(2)].
iv. Working Solution of C-13-labeled OH-PAH. For each C-13-labeled OH- PAH,
make 100 ng/µL of the stock solution, combine and dilute aliquots of the
individual C-13-labeled OH-PAH solutions with acetonitrile to produce the
working solution with 100 pg/µL of each C-13- labeled OH-PAH. Use argon to
displace any air in the vials. Then cap the vials and store them at -80 °C until
needed (for up to12 months).
v. Mass Spectrometric Check Solution. Use this solution at least weekly to
monitor the operating performance of the GC column and the mass spectrometer.
Use a solution of 10 fg/µL of a tetra-chlorinated dioxin (2378 TCDD) as the
check solution. For a 1-µL injection, a minimum signal-to-noise ratio (using 4
standard deviations of baseline noise) of 4 is required. Use the ion intensity of
mass 321.894 for the signal-to-noise ratio measurement.
b. Manual Equipment (indicated manufacture or its equivalent)
(1) Water bath/sonicator (Cole Parmer, Vernon Hills, IL).
(2) Incubator (Fisher Scientific, Pittsburgh, PA).
(3) Oven for derivatization (Cole Parmer, Vernon Hills, IL).
(4) Microbalance (Sartorius Ultramicro, Westbury, NY).
(5) TurboVap® LV evaporator (Zymark Corp., Hopkinton, MA).
(6) Centrifuge 5804 (Eppendorf Corp., Westbury, NY)
(7) Repeater Plus (Eppendorf Corp., Westbury, NY)
(8) Vortex Genie vortex mixer (Scientific Industries Inc., Springfield, MA).
c. Other Materials (indicated manufacture or its equivalent)
(1) Miscellaneous glassware (Pyrex or Kimax, Scientific Services).
(2) 1.5ml amber autosampler vials (National Scientific, Inc.).
(3) 1.1ml 12x32mm, Pulled PT Vial (Sun Sri, Rockwood, TN)
(4) 4-mL, amber screw-top vials (Supelco, Inc.).
(5) 10-ml screw-top culture tubes
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Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
(6) 15-mL conical centrifuge tubes (Kimble, Vineland, NJ).
(7) 2-micron filter (Nalgene, Rochester, NY)
(8) Pipetman 10µL, 25µL, 100µL, 250µL,1mL, 5mL (Gilson Co., Middletown,
WI)
d. Instrumentation (indicated manufacture or its equivalent)
Perform the analyses on a Finnigan MAT -95XL high-resolution mass spectrometer
that is equipped with an electron impact ionization source and is interfaced to a
Thermo Finnigan Trace Ultra 2000 gas chromatograph system (Thermo Finnigan,
San Jose, CA). A PAL injection system (CTC Analytics, Switzerland) handles the
GC injections automatically. All instruments are connected and controlled by a Dell®
computer with Microsoft® Windows XP® operating system
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Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
(1) High Resolution Mass Spectrometer (HRMS) Configuration (see Table 4)
Table 4. Thermo Finnigan MAT 95 XL HRMS Configuration
MS Parameter
Setting
Scan mode
Multiple ion detection
Ionization type
Electron impact
Ion polarity mode
Positive
Electron energy
40 eV
Resolution
10,000
Ion source
260 °C
Transfer line
290 °C
Conversion dynode voltage
Positive
Continuous dynode electron
1.45 -2.25 kV (106 gain)
multiplier voltage
(2) Masses and retention times of targeted OH-PAHs on MAT 95 XP HRMS are
shown in the Table 5.
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Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
Table 5. Masses and Retention Time of Targeted OH-PAHs
Analyte-O-Si (CH3)3
Mole. Mass
Ion Mass
R.T. min
1-nap
C6 1-nap
2-nap
9-fluo
13
C6 9-fluo
3-fluo
13
C6 3-fluo
2-fluo
13
C6 2-fluo
4-phen
9-phen
3-phen
13
C6 3-phen
1-phen
2-phen
13
C6 2-phen
1-bcp
3-flran
13
C6 3-flran
1-pyr
13
C6 1-pyr
2-bcp
1-baa
13
C6 1-baa
4-chry
6-chry
13
C6 6-chry
3-bcp
13
C6 3-bcp
3-chry
13
C6 3-chry
1-chry
3-/9-baa
2-chry
3-bap
13
C6 3-bap
7-bap
216.0970
222.1172
216.0970
254.1127
260.1328
254.1127
260.1328
254.1128
260.1328
266.1127
266.1127
266.1127
272.1328
266.1127
266.1127
272.1328
316.1283
290.1127
296.1328
290.1127
296.1328
316.1283
316.1283
322.1485
316.1283
316.1283
322.1485
316.1283
322.1485
316.1283
322.1485
316.1283
316.1283
316.1283
340.1282
346.1484
340.1282
201.0735
207.0937
201.0735
239.0892
245.1093
239.0892
245.1093
239.0892
245.1093
251.0890
251.0890
251.0890
257.1093
251.0890
251.0890
257.1093
301.1048
275.0892
281.1093
275.0892
281.1093
301.1048
301.1048
307.1250
301.1048
301.1048
307.125
301.1048
307.1250
301.1048
307.1250
301.1048
301.1048
301.1048
325.1042
331.1249
325.1042
8.44
13
15
I-Std.
x
8.70
11.13
12.65
12.85
13.73
14.10
14.37
x
14.43
14.73
16.79
17.03
x
17.40
x
19.07
19.13
x
19.22
19.30
x
19.71
x
20.03
20.10
20.35
20.43
23.63
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
(3) Gas Chromatography (GC) Configuration and Temperature Program
Chromatographic separation is performed on a Finnigan Thermo Trace GC
Ultra 2000 gas chromatograph fitted with a J&W DB-5MS, 25-m, fused silica
capillary column. The column ID is 0.25 mm and the film thickness is 0.25
micron (J&W, # 22-5022 or its equivalent). The GC purge flow is 10 mL/min,
the saver time is 2 min, and the saver flow is 20 mL/min. The temperature
program lasts a total of 33.3 min. (See Table 6 for GC Configuration and Table
7 for the GC Temperature Program.)
Table 6. GC Configuration
GC Parameter
Setting
Carrier gas
Helium
Constant flow rate
1.0 ml/minute
Injection mode
Splitless
Injector purge delay
2.0 minutes
Injector temperature
270 °C
Mode
Constant pressure
Table 7. GC Oven Temperature Program for Hydroxy PAHs
Time (minutes)
Temperature ('C)
0
100
2
100
6
160
19.5
295
25.5
295
26
300
35
300
16
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
6. Calibration and Calibration-Verification Procedures
a. Mass Spectrometer
Calibrate and tune the Thermo Finnigan MAT 95 XP mass spectrometer using
FC43 (perfluorotributylamine) according to the instructions in the operator's
manual. After calibrating the instrument with 10,000 resolution and maximum
sensitivity, prepare the instrument to analyze the PAH metabolites (see Section
8).
b. Calibration Curve
(a). Construct a 6-point calibration curve by performing a weighted regression
(i.e., weighted to 1/concentration) analysis of relative response factor (i.e.,
area native/area internal label) versus standard concentration. Perform a
minimum of seven repeat determinations for each point on the standard
curve.
(b). The lowest point (10 ng/L) on the calibration curve is near the measurable
detection limits; the highest point (10,000 ng/L) is above the expected range
of normal results.
(c). Measure and calculate blank levels; subtract the blank amounts from the
calibration points.
(d). Determine the slope and intercept of the calibration curve by linear least
squares fit with weighted 1/concentration using QuanBrowser®,
QuanDesk® , or SAS® software.
(e). R-squared values for the curve must be greater than 0.90. Linearity of
standard curves should extend over the entire standard range. Intercepts
(calculated from the least squares fit of the data) should not be significantly
different from 0; if they are, then identify the source of bias, make necessary
corrections, and run again.
(f). Periodically recalculate the standard curve to incorporate the newest data
points. Reestablish the standard curve when new working standard
solutions or new isotope solutions are prepared.
c. Calibration Verification
17
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
(a). Analyze the calibration-verification materials after any substantive change
in the method or instrumentation occurs to verify the integrity of the
calibration curve, slope, linearity, and dynamic range (e.g., the instrument
has used in another method; installed a new column; performed
preventative maintenance; or cleaned the ion source of the mass
spectrometer).
(b). Perform calibration verification at least once every 6 months while the
method is in use.
(c). If there is a significant difference from the established
calibration-verification pool limits, stop doing analyses using this method
until you can correct the problem and ensure that calibration-verification
materials are consistent with the calibration curve.
(d). Document all calibration-verification runs and results.
d. Proficiency Testing (PT)
Because no standard reference materials are available for urinary analysis of
hydroxy-PAH levels within an analytical study, duplicate measurements of
hydroxy-PAH levels were performed on a series of selected individual samples
at designated intervals during sample analysis. The analytical reproducibility of
a set of individual samples where levels of duplicate samples were determined
after every calculated sample increment in the study was considered an
acceptable measure of the proficiency of the method. The calculated increment
is a value that ranges from N/0.05N to N/0.02N (N= number of samples in the
study). PT criteria are under evaluation.
7. Operating Procedures; Calculations; Interpretation of Results
a. Sample Preparation
Allow unknown urine samples, QC samples, and a blank (2-mL o.p. water) to
thaw slowly in a refrigerator overnight to avoid cracking the glass containers.
b. Hydrolysis
In this stage, carefully pre-washed culture tubs with screw-cap tops, caps with
PTFE liner, glass pipets, and conical centrifugal tubes are used. Aliquot 2 mL of
18
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
urine into 10mL culture tube. Add 3mL enzymatic-buffer (pH=5.0, with
β-glucuronidase / sulfatase enzyme 300 units/ml, derived from Helix Pomatia),
and 10µL of combined C-13-labeled standards (100 pg/µL of each labeled
compound). Prepare QC samples, the same way. Aliquots of calibration
standards and QCs are usually made earlier in batches and stored in a freezer.
Place the caps loosely on the tubes and use a vortex mixer to mix the resulting
solution well. Incubate the samples at 37 °C over night. Remove samples from
the incubator and cool down them for a brief period. Urine samples can be
hydrolyzed and then place them in a refrigerator for extraction in the following
morning. (Note: This is an acceptable stopping point if you immediately
refrigerate the hydrolysates.) For the blank, and the calibration standard the solid
phase extraction should be done same day of the preparation.
c. Extraction
Add 5mL pentane to hydrolyzed samples tube. Screw on cap, mix and vent
pressure twice. Screw on cap tightly and mix samples by shaking rocker for 5
min. Evenly place the culture tubes on rocker of Eppendorf centrifuger and
centrifuge for 15min at 3000rpm, check the separation and set another 15min
run. Upper layer solvent transferred to a cleaned conical centrifugal tubes using
glass pipet. Due to the extracts are directly concentrated without further dry-up
in next stage, the transferring the solvent needs special care, no aqueous is
allowed to touch. Extraction repeated with another 5mL of pentane. Add 5µL
dodecane (keeper) to each tube prior to further concentrate.
d. Concentration
Concentrate the extracts using a TurboVap® (Caliper Life Sciences), set at 40
°C and with 5 psi of nitrogen, the final volume is about 10µL. The evaporation
takes approximately 10 minutes (Do not let the nitrogen stop until remove the
tubes from TurboVap®). Reconstitute the residual with 20µL high purity
toluene. Add 10µL PCB-61 (50pg/µL) as the external recovery standard (ERS),
use vortex mixer 15 seconds and transfer solution into a cleaned pulled 1.1 ml
GC vial use 100 µL pipettor.
e. Derivatization Procedure
19
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
The derivatization step converts the OH functional group to an O-trimethylsilyl
group. This step produces better limits of detection (LOD) and chromatography.
To derivatize the analytes after evaporation, add 20 µL of MSTFA in each vial
and then displace the air in the vial with a gentle stream of argon. Quickly screw
the vial. Place the vials in an incubator set at 60 °C for 1hour. Cover the samples
with aluminum foil. The derivatized samples are then ready for analysis on the
mass spectrometer. The samples can also be stored in a refrigerator (-4 °C) for
up to 1 week.
f. Analysis
Preliminary MAT 95 XL System Setup and Performance Check
(a) In the TUNE window, adjust the resolution between 9950 and 10050 using
2 µL of FC43.
(b) Run a GC/HRMS analysis of 10 fg tetra-chlorinated dioxin, check the
solution, and verify chromatographic resolution and peak intensity.
(c) In the logbook, record the signal-to-noise ratio of the check compound.
g. Processing of Data
(1) Quantification
All raw data files are quantified using the quantitation software of the MAT 95
XP in the QUAN window. This allows manual peak selection and baseline
determination for each ion. The entire quantification procedure is accomplished
by using the user buttons defined in the QUAN application.
(2) Transfer of Data
Use the USB jump drive or CD-R/RW copy the data files to other computer.
(3) Backup Data
Backup data to CD-R or other net hard drive weekly.
(4) Statistical Analysis and Interpretation of Data
Export information in the cleanup and mass spectrometry database tables from
the database to a fixed text (ASCII) file, and then import the file into SAS® .
Use SAS® programs for standard curve generation, QC analysis, blank analysis,
limit-of-detection determination, unknown calculations, data distribution, etc.
as needed.
20
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
h. Replacement and Periodic Maintenance of Key Components
(1) Routine Maintenance
(a) MAT 95 XL Mass Spectrometer
(i) Check cooling water level and temperature monthly.
(ii) Clean the ion volume or replace it monthly.
(iii) Clean the ion source or replace it annually.
(iv) Replace the calibration gas septum every two weeks.
(v) Trained Thermo Finnigan technicians will perform all other
maintenance based on an annual schedule or as requested.
(b) Trace Ultra 2000 GC gas chromatograph
(i) Change the injection port liner and septum daily.
(ii) Clean the injection port, clean or replace the gold seal monthly. (iii)
Replace the GC column at 1000 analyses or sooner.
(iv) Replace Helium tank when the pressure is lower than 500 psi.
(Note: The above maintenance schedules may be accelerated if necessary.)
(2) Performance Maintenance
Perform maintenance procedures if you detect a decrease in system
performance (i.e., sensitivity and/or S/N ratio) without other apparent technical
reasons.
8. Reportable Range of Results
The linear range of the standard calibration curves determines the highest and lowest
analytical values of an analyte that are reportable. The calibration verification of the
method encompasses this reportable range. However, you can dilute and analyze a urine
sample with an analytical data value exceeding the highest reportable limit so that the
result will be within the reportable range.
a. Linearity Limits
Analytical standards were linear for all analytes through the range of concentrations
evaluated. The linear range for all analytes was 10 ng/L to 5,000 ng/L. Urine samples
whose concentrations exceed these ranges must be analyzed again with a diluted
solution or using a smaller aliquot.
21
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
b. Analytical Sensitivity
The method detection limit (MDL) is defined as 3 times the standard deviation (SD)
at zero concentration (3SD). It is determined by weighted regression
(1/concentration) analysis of the absolute SD versus the concentration. For analytes
with detectable blank signals, the MDL is calculated by adding the average blank
level to 3SD (see Table 8 for the MDL determined for the analytes). Generally, MDL
range from 2ng/L to 10 ng/L, depending upon blank levels.
22
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
Table 8. Method Detection Limits (MDLs)
Analyte
MDL (ng/L)
1-nap
5.7
2-nap
4.7
2-fluo
4.4
3-fluo
7.0
9-fluo
2.0
1-phen
8.0
2-phen
4.4
3-phen
1.2
4-phen
1.3
9-phen
1.9
3-flran
5.8
1-pyr
4.9
1-bcp
4.5
2-bcp
2.2
3-bcp
6.9
1-chry
4.8
2-chry
3.8
3-chry
1.3
4-chry
9.5
6-chry
5.3
1-baa
8.6
3-baa
8.7
3-bap
72.1
23
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
c. Accuracy
Enriching urine samples with known concentrations of the OH-PAH and comparing
the calculated and expected concentrations determine the accuracy of the method.
The accuracy can be expressed as the slope and the intercept of a weighted regression
(1/concentration) analysis of the expected values versus the calculated values. A
slope of 1.0 and an intercept of 0 indicate that the results are identical. The method
accuracy is shown in Table 9.
24
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
Table 9. Accuracy of the Method
Weighting
Analyte
Slope
Intercept
R-Squared
1-nap
0.0015489
0.0142736
0.9982
1/ Conc.
2-nap
0.0016431
0.00441331
0.9982
1/ Conc.
2-fluo
0.0029785
0.00425533
0.9968
1/ Conc.
3-fluo
0.0019075
0.0050077
0.9975
1/ Conc.
9-fluo
0.0014534
0.000940282
0.9971
1/ Conc.
1-phen
0.0029675
0.00299927
0.9969
1/ Conc.
2-phen
0.0026923
0.005438
0.9979
1/ Conc.
3-phen
0.0028350
0.00563754
0.9959
1/ Conc.
4-phen
0.0029070
0.00333788
0.9972
1/ Conc.
9-phen
0.0021514
0.00336125
0.9983
1/ Conc.
3-flran
0.0015743
0.00224427
0.9975
1/ Conc.
1-pyr
0.0025646
0.00356015
0.9958
1/ Conc.
1-bcp
0.0013202
0.00498609
0.9939
1/ Conc.
2-bcp
0.0016979
0.00632489
0.9973
1/ Conc.
3-bcp
0.0019940
0.00548789
0.9961
1/ Conc.
1-chry
0.0034276
0.0211208
0.9962
1/ Conc.
2-chry
0.0017045
0.00689675
0.9962
1/ Conc.
3-chry
0.0028450
0.0210635
0.9977
1/ Conc.
4-chry
0.0035895
0.00712345
0.9987
1/ Conc.
6-chry
0.0021580
0.00605751
0.9950
1/ Conc.
1-baa
0.0020282
0.00339295
0.9917
1/ Conc.
3-/9-baa
0.0007313
0.00185813
0.9968
1/ Conc.
3-bap
0.0009369
-0.00932439
0.9940
1/ Conc.
25
index
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
d. Precision
The precision of this method is reflected in the variance of QC samples over time.
The major contributor to the overall coefficient of variation (CV) is the variation
between runs. (See Table 10 and Table 12 for CV values.)
9. Quality Control (QC) Procedures
a. QC Material
Use urine pools enriched with known amounts of OH-PAH as the control materials
for each analytical run.
b. Urine Enrichment
Split the urine pool into four smaller urine pools. Reserve the first pool for blank
check. Enrich the second pool with the 23 OH-PAH working solution to yield a low
pool with an added concentration of 100 ng/L. Enrich the third pool with the 23 OHPAH working solution to yield a middle pool with an added concentration of 300
ng/L. Enrich the fourth pool with the 23 OH- PAH working solution to yield a High
pool with an added concentration of 900 ng/L.
c. Dispensing
Dispense 2-mL aliquots of urine into screw-capped vials. Mark the vials
appropriately with identification stickers and store the QC materials at -70 °C until
time of analysis. Buffer and internal standards could be added at the day of analysis
when unknown urines are prepared.
d. Characterization of QC Materials
Characterize the QC pools (including the unspiked pool) by 20 consecutive runs of
each QC material. Use the data from these runs to establish the mean and upper- and
lower- 99th and -95th confidence intervals. Determine the confidence intervals and
adjust them according to the number of each QC material analyzed in each run.
e. Use of QC Samples
During each analytical run, analyze at least one QC material from each pool.
f. Final Evaluation of QC Results
26
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
After the completion of a run, consult the QC limits to determine if the run is in
control. The following QC rules apply to the average of the beginning and
ending analyses of each of the bench QC pools:
(1) If both the low and the high QC results are within the 2s limits, then accept the
run.
(2) If one of two QC results is outside the 2s limits, then apply the rules below and
reject the run if any condition is met.
(Note: each one is given a code [0- 4] to be entered in the database.)
Code
0 -Extreme outlier: the result is outside the characterization mean by more than 4SD.
1 -13s -The average of both low QC results QB the average of both high QC results is
outside a 3s limit.
2 –22s -The average of both low QC results AND the average of both high QC results is
outside a 2s limit on the same side of the mean.
3- R4s 5equential- The average of both low QC results AND the average of both high
QC results is outside a 2s limit on opposite sides of the mean.
4 -1Ox sequential -The previous nine average QC results (for the previous nine runs)
were on the same side of the mean for either the low QB high QC results.
If the run is declared out of control, the analysis results for all patient samples analyzed
during that run are invalid for reporting. If more than ten consecutive QCs are on the
same side of the mean of the characterized QC material, suspend all operations until
you determine whether a bias is present in the method. (See Tables 10- 12 for the
characterization of both QC pools.)
27
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
Table 10. Mean Value, SD, and CV of Low QC Pool
(Replicates =20)
Analyte
Mean (ng/L)
SD
CV
1-nap
231
30
25
2-nap
590
66
50
2-fluo
166
29
24
3-fluo
114
17
13
9-fluo
108
19
15
1-phen
168
25
19
2-phen
146
12
8
3-phen
171
24
17
4-phen
166
29
24
9-phen
100
12
9
3-flran
116
8
5
1-pyr
135
7
4
1-bcp
66
14
12
2-bcp
95
10
8
3-bcp
93
6
4
1-chry
88
9
6
2-chry
98
13
9
3-chry
98
11
7
4-chry
82
9
7
6-chry
90
17
11
1-baa
90
10
7
3-baa
104
16
11
3-bap
137
20
5
28
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
Table 11. Mean Value, SD, and CV of Middle QC Pool
(Replicates =20)
Analyte
Mean (ng/L)
SD (%)
CV
1-nap
369
41
34
2-nap
781
59
44
2-fluo
357
72
59
3-fluo
317
71
54
9-fluo
326
80
72
1-phen
429
94
76
2-phen
361
63
47
3-phen
291
16
11
4-phen
357
73
59
9-phen
214
45
33
3-flran
238
13
9
1-pyr
248
12
10
1-bcp
173
24
18
2-bcp
222
17
10
3-bcp
222
13
9
1-chry
215
16
12
2-chry
246
23
20
3-chry
234
17
15
4-chry
195
21
17
6-chry
221
26
19
1-baa
219
17
15
3-baa
248
25
19
3-bap
288
51
36
29
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
Table 12. Mean Value, SD, and CV of High QC Pool
(Replicates =20)
Analyte
Mean (ng/L)
SD
CV
1-nap
930
82
60
2-nap
1189
127
93
2-fluo
806
90
73
3-fluo
766
97
71
9-fluo
656
97
71
1-phen
868
94
73
2-phen
813
63
42
3-phen
862
47
35
4-phen
801
81
67
9-phen
656
97
67
3-flran
752
55
43
1-pyr
789
55
45
1-bcp
628
82
64
2-bcp
790
49
37
3-bcp
765
31
22
1-chry
759
70
54
2-chry
859
88
72
3-chry
812
78
55
4-chry
698
82
64
6-chry
813
107
84
1-baa
762
57
45
3-baa
861
105
84
3-bap
1148
161
116
30
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
10. Recovery of Method
The recoveries of OH-PAHs use this method are calculated based on the amount of
spiked isotope labeled internal standards vs measured amount with the external
recovery standard correction. The recovery values reflect the performance of sample
preparation.
Table 13 Internal Standard Acceptable Recovery Ranges
Spike
Recovery Range, %
1-OH-Naphthol C13
35-95
3-OH-Phenanthrene C13
35-95
3-OH-Fluoranthene C13
35-95
1-OH-Pyrene C13
50-120
1-OH-Benzo(a)anthracene C13
50-120
6-OH-Chrysene C13
50-120
3-OH-Benzo(c)phenanthrene C13
50-120
31
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
11. Remedial Action if Calibration or QC Systems Fail to Meet Acceptable Criteria
If the calibration or QC systems fail to meet acceptable criteria, suspend all operations
until you identify the source or cause of failure. If you can easily identify the source of
failure (e.g., failure of the mass spectrometer or an error in pipeting), then correct the
problem. Otherwise, prepare fresh reagents and clean the mass spectrometer system.
Before beginning another analytical run, reanalyze several QC materials (in the case of
QC failure) or calibration-verification materials (in the case of calibration failure).
After reestablishing calibration or QC, resume analytical runs.
12. Limitations of Method; Interfering Substances and Conditions
This method is an isotope-dilution mass-spectrometry method, which is widely
regarded as the definitive method for the measurement of organic toxicants in human
body fluids. By using high-resolution mass spectrometry, it eliminates most
interferants. Occasional unknown interferants have been encountered because of the
matrix used in this procedure. Chromatographic interferences with the internal
standards will result in the rejection of analysis. If repeat analysis results in an
interference with the internal standard, do not report the results for that analyte.
13. Reference Ranges (Normal Values)
The reference ranges for OH-PAH in the U.S. population are based on the NHANES
2005 study. (See Table 14 for reference range values from NHANES 2005.)
32
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
Table 14. Reference Range of OH-PAHs in Urine
Analyte
1-nap
Without Creatine Correction
Mean
Low 50th High 95th
95% C.I.
(ng/L)
(ng/L)
(ng/L)
2050
1490
26600
Creatine Corrected
Mean
Low 50th High 95th
95% C.I.
(ng/L)
(ng/L)
(ng/L)
1910
1370
20800
2-nap
2470
1920
29700
2310
1670
19200
2-fluo
441
422
9470
408
382
6860
3-fluo
170
86.3
4680
157
79.9
4060
9-fluo
219
185
1300
205
181
1120
1-phen
154
105
1390
142
102
1270
2-phen
98.3
79.7
937
90.3
67.8
748
3-phen
127
113
721
116
101
574
4-phen
41.9
46.0
339
39.2
56.5
411
9-phen
33.9
36.0
396
31.7
36.3
290
3-flran
13.4
17.5
147
12.3
14.7
127
1-pyr
79.8
76.9
926
74.2
63.1
607
1-bcp
*
< LOD
54.0
*
< LOD
70.8
2-bcp
*
< LOD
28.1
*
< LOD
30.9
3-bcp
*
< LOD
16.0
*
< LOD
16.7
1-chry
*
< LOD
138
*
< LOD
104
2-chry
*
< LOD
45.0
*
< LOD
35.0
3-chry
*
< LOD
46.0
*
< LOD
62.5
4-chry
*
< LOD
< LOD
*
< LOD
< LOD
6-chry
*
< LOD
10.1
*
< LOD
76.4
1-baa
*
< LOD
30
*
< LOD
32.4
3-/9-baa
*
< LOD
31.0
*
< LOD
35.5
3-bap
*
< LOD
251
*
< LOD
248
< LOD means less than the limit of detection
* Not calculated. Portion of results below limit of
From CDC Third Report on Human Exposure to Environmental Chemicals
33
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
14. Critical-Call Results ("Panic" Values)
There are no established critical-call values for this method. It is unlikely that any result
would be a critical-call, which would only occur with poisonings.
15. Specimen Storage and Handling During Testing
Refrigerate urine samples overnight at -4 °C to expedite thawing prior to aliquoting the
samples. Store the urine extracts in autosampler vials at -70 °C after analysis. Current
studies indicate (CDC data) that the extracts are stable for up to 3 weeks.
16. Alternate Methods for Performing Test and Storing Specimens if Test System
Fails
The method is designed to run on a GC/HRMS instrument and is not generally
transferable to other instrumentation.
There are no acceptable alternative methods for analysis or backup systems. If the
analytical system fails, store specimens in a refrigerator overnight. If long-term
interruption is anticipated, store at -80 °C.
17. Transfer or Referral of Specimens; Procedures for Specimen Accountability and
Tracking
Use standard record-keeping systems (i.e., notebooks, sample logs, data files,
creatinine logs, demographic logs) to keep track of all specimens.
34
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
References
1. International Agency for Research on Cancer. IARC Monographs on the Evaluation of
Carcinogenic Risk of Chemicals to Man: Polycyclic Aromatic Compounds. Part 1.
Chemical and environmental data 1983; Vol 32. (IARC, Lyon).
2. International Agency for Research on Cancer. IARC Monographs on the Evaluation of
Carcinogenic Risk of Chemicals to Man: Tobacco Smoking 1985; Vol. 38. (IARC,
Lyon).
3. Angerer J, Mannschreck C, GOndel J. Biological monitoring and biochemical effect
monitoring in the case of PAH exposure. Int Arch Environ Health 1997; 70: 365.
4. Chaung JC, Callahan PJ, Lyu CW, Wilson NK. Polycyclic aromatic hydrocarbon
exposures of children in low-income families. J Expos Anal Environ Epidemiol 1999;
2: 85.
5. Dor.F;Haguenoer J-M, Zmirou D, Empereur-Bissonnet P, Jongeneelen FJ, Nedellec V,
Person A, Ferguson CC. Urinary 1-hydroxypyrene as a biomarker of polycyclic
aromatic hydrocarbons exposure of workers on a contaminated site: Influence of
exposure conditions. J Occup Environ Medicine 2000; 42: 391.
6. Gmeiner G, Krassnig C, Schmid E, Tausch H. Fast screening method for the profile
analysis of polycyclic aromatic hydrocarbon metabolites in urine using derivatisationsolid phase microextraction. J Chromatog B 1998; 705: 132.
7. Grimmer G, Jacob J, Dettbarn G, Naujack K-W, Heinrich U. Urinary metabolite profile
of PAH as a potential mirror of the genetic disposition for cancer. Exp Toxic
Patho11995; 47: 421.
8. Grimmer G, Jacob J, Dettbarn G, Naujack K-W. Determination of urinary metabolites of
polycyclic aromatic hydrocarbons for the risk assessment of PAH-exposed workers. Int
Arch Occup Environ Health 1997; 69: 231.
9. GOndel J, Angerer J. High performance liquid chromatographic method with
fluorescence detection for the determination of 3-hydroxybenzo(a)pyrene and 3hydroxybenzo(a)anthracene in the urine of polycyclic aromatic hydrocarbon exposed
workers. J Chromatog B 2000; 728: 47.
10. GOndel J, Schaller KH, Angerer J. Occupational exposure to polycyclic aromatic
hydrocarbons in a fireproof stone producing plant: biological monitoring of 1hydroxypyrene, 1-,2-,3- and 4- hydroxybenz(a)anthracene and 3hydroxybenzo(a)pyrene. Int Arch Occup Environ Health 2000; 73: 270.
11. Hansen AM, Christensen JM, Sherson D. Estimation of reference values for urinary
1-hydroxypyrene and alpha-naphthol in Danish workers. Sci Total Environ 1995; 163:
211.
35
Standard Operating Procedure - Hydroxy PAHs in Urine
July 2006
12. CDC, Third National Report on Human Exposure to Environmental Chemicals. NCEH
Pub. 2005; No. 05-0570, 77-131
13. Zheng Li, Lovisa C. Romanoff, Debra A. Trinidad, Measurement of Urinary
Monohydroxy Polycyclic Aromatic Hydrocarbons Using Automated Liquid-Liquid
Extraction and Gas Chromatography/Isotope Dilution High-Resolution Mass
Spectrometry, Anal. Chem. 2006;
36
Standard Operating Procedure - Hydroxy PAHs in Urine
37
July 2006
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