EPA Method 8270 for SVOC Analysis on the 5977A Series GC/MSD Author Dale R. Walker Agilent Technologies Santa Clara CA, 95636 Application Note Introduction Several environmental agencies in the world use the methodology described by the United States Environment Protection Agency (USEPA) in Method 8270, which uti- lizes gas chromatography/mass spectrometry (GC/MS) to analyze solid, liquid and gaseous samples for semi-volatile organic compounds. Method 8270 presents sev- eral analytical challenges due to the requirement for simultaneous measurement of acid, base, and neutral compounds over a wide concentration range. Many laboratories strictly follow the method and typically analyze more than 70 compounds in a single analytical run, at a working concentration range between 20–160 parts per million (ppm), while a growing number of laboratories are pushing for lower detection limits and a wider dynamic range. New instrumentation, tech- nologies and techniques are constantly evolving to meet these analytical demands.
12
Embed
EPA Method 8270 for SVOC Analysis on the 5977A Series GC/MSD
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
EPA Method 8270 for SVOC Analysis onthe 5977A Series GC/MSD
Author
Dale R. Walker
Agilent Technologies
Santa Clara CA, 95636
Application Note
Introduction
Several environmental agencies in the world use the methodology described by theUnited States Environment Protection Agency (USEPA) in Method 8270, which uti-lizes gas chromatography/mass spectrometry (GC/MS) to analyze solid, liquid andgaseous samples for semi-volatile organic compounds. Method 8270 presents sev-eral analytical challenges due to the requirement for simultaneous measurement ofacid, base, and neutral compounds over a wide concentration range.
Many laboratories strictly follow the method and typically analyze more than70 compounds in a single analytical run, at a working concentration range between 20–160 parts per million (ppm), while a growing number of laboratories are pushingfor lower detection limits and a wider dynamic range. New instrumentation, tech-nologies and techniques are constantly evolving to meet these analytical demands.
2
This Application Note describes the use of the highly inertand sensitive Agilent 5977A Series GC/MSD, coupled to theAgilent 7890B GC, to meet the performance requirements ofthe USEPA 8270 method over a working range of 0.2–100 ppm(Figure 1). The inert Extractor EI source, which has an opera-tional temperature of up to 350 °C, plays a major role in delivering improved sensitivity. While Agilent MassHunterWorkstation software was used for data acquisition andanalysis, the 5977A Series GC/MSD continues to be compatible with the GC/MSD ChemStation data analysis software.
Experimental
Reagents and StandardsEPA 8270 GC-MS tuning solution containing benzidine, 4,4′- dichlorodiphenyltrichloroethane (DDT), decafluorotriph-enylphosphine (DFTPP), and pentachlorophenol was used toevaluate the tuning of the 5977A Series GC/MSD. The calibra-tion and performance evaluation standards were spiked withinternal standard at a concentration of 5 ppm.
InstrumentsThis method was developed on the Agilent 5977A GC/MSDcoupled to the Agilent 7890B Gas Chromatograph using asplit/splitless inlet and the Agilent G1544-8070 liner. Theinstrument conditions used are shown in Table 1. MassHunterWorkstation software was used for data acquisition and processing.
Figure 1. Total compound chromatogram (TCC) of 20 ppm standard.
Table 1. Agilent 7890 GC and Agilent 5977A Series GC/MSD InstrumentConditions
Injection mode Pulsed splitless, 25 psi for 1 minute
Oven temperature gradient 0.5 minute hold at 40 °C
40 °C to 100 °C at 10 °C/min, hold for 0 minutes
100 °C to 260 °C at 25 °C/min, hold for 0 minutes
260 °C to 280 °C at 5 °C/min, hold for 0 minutes
280 °C to 320 °C at 15 °C/min, hold for 2 minutes
Carrier gas Helium, constant flow at 1.2 mL/min
Transfer line temperature 280 °C
Run time 21.6 minutes
MS conditions
Ion source temperature 300 °C
Quadrupole temperature 150 °C
Ionization EI mode
Scan mode Full scan, m/z 35–500
EMV mode Gain factor
Gain factor 0.30
Resulting EM voltage 1,259.3 V
Solvent delay 2.5 minutes
*This column is used in the 0.2 to 100 ppm detection range, and the DB-UI8270D 30 m × 250 µm, 0.50 µm column (p/n 122-9736) is used in the 20 to160 ppm detection range.
6.5
×106
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
05 6 7 8 9 10 11 12 13
Acquisition time (min)
Coun
ts
14 15 16 17 18 19 20 21
3
Results and Discussion
Instrument TuningThe 5977A Series GC/MSD was tuned using both Atune andEtune automatic tuning algorithms. The Etune algorithm pro-vides the optimal condition for stability and sensitivity for the5977A Series GC/MSD system. A voltage is applied to theextractor lens and ion body which accelerates and focusesthe ions from the ionization volume. This provides higher iontransfer into the quadrupole and in turn improves the instru-ment sensitivity. This increase in sensitivity favors highermasses and, therefore, produces a DFTPP spectrum with a tiltdifferent than the tuning criteria outlined in Method 8270(Table 2). However, Method 8270B does allow for alternativetuning criteria if published and recommended by a manufacturer (§11.3.1).
The system tune performance for both tuning algorithms wasevaluated using a 1-µL injection of a 50 µg/mL DFTPP solu-tion. For Etune, the obtained DFTPP spectrum was comparedto that of the NIST library, and it demonstrated a proper tuneby meeting a match factor score of greater than 90 (Figure 2).
Atune was evaluated using the traditional DFTPP criteria setforth by the USEPA as listed in Table 2. MassHunterQuantitative Analysis was used to determine if the DFTPPions produced by the tuned system met the EPA criteria. BothEtune and Atune passed their respective evaluative criteria.
Table 2. USEPA Tuning Criteria for DFTTP
Mass (m/z) Ion abundance criteria
51 10-80% of Base peak
68 <2% of mass 99
70 <2% of mass 69
127 10-80% of Base peak
197 <2% of mass 198
198 Base peak, or >50% of mass 442
199 5-9% of mass 198
275 10-60% of Base peak
365 >1% of mass 198
441 Present but <24% of mass 442
442 Base peak, or >50% of mass 198
443 15-24% of mass 442
Figure 2. Evaluation of the instrument performance by spectral matching DFTPP to the NIST library.
4
Initial CalibrationA multipoint calibration was run and the relative responsefactor was determined for each concentration of each compo-nent of the calibration standard (Figure 3). The meanresponse factor was then calculated across all of the averagerelative response factors for the calibration curve of eachcompound, along with its relative standard deviation (RSD).Table 3 displays the mean response factor and RSD. Due to
the large number of compounds analyzed by this method,some compounds may fail to meet the Method 8270 relativeresponse factor criterion of an RSD less than 20%. In suchcases, an alternate curve fit algorithm is employed (in thiscase linear). When a linear curve fit is used, it is noted with a(-------) in the %RSD column in Table 3 and the calibrationcoefficient (R2) of the fit is displayed instead of the RSD.
Figure 3. Evaluation of calibration using Agilent MassHunter Quantitative Analysis, in this case using the nitrobenzene component of the 8270 test mix.
5
Table 3. Calibration Curve Data for 84 Compounds Specified by Method 8270
Average response factor determined at each of 11 points on the calibration curve
*Mean response factor calculated across all of the average response factors
Method Reproducibility StudyTen replicates of the 8270 low standard, 0.2 ppm, were run toillustrate system reproducibility and accuracy (Table 4). Morethan 80% of the compounds exhibited RSDs below 6%, withseveral below 2%.
7
Table 4. Ten Replicate Determinations of 0.2 ppm Samples of Each of 84 Analytes
Tune ComparisonsUsing Etune provides an increase in signal area counts bymore than a factor of two over Atune, offering the potential ofreaching lower detection limits (Table 5). The RSD values forthe Etune results are generally equivalent or lower.
Table 5. Comparison of Raw Peak Areas at 0.2 ppm for Atune and Etune
Etune area Atune areaRatio Etune/Atune area Etune %RSD Atune %RSD
Table 5. Comparison of Raw Peak Areas at 0.2 ppm for Atune and Etune (continued)
Etune area Atune areaRatio Etune/Atunearea Etune %RSD Atune %RSD
Dimethyl phthalate 113728 41251 2.76 3% 2%
Acenaphthylene 155179 57453 2.70 3% 3%
3-Nitroaniline 7467 2762 2.70 4% 7%
2,6-Dinitrotoluene 349976 136026 2.57 2% 1%
Acenaphthene 139129 48627 2.86 2% 1%
Dibenzofuran 203450 70580 2.88 2% 2%
2,4-Dinitrotoluene 7002 2421 2.89 6% 7%
Diethyl phthalate 76983 30769 2.50 3% 3%
Fluorene 142357 50280 2.83 2% 2%
4-Chlorophenyl-phenylether 87024 29242 2.98 2% 2%
4-Nitroaniline 7294 2703 2.70 4% 5%
N-Nitrosodiphenylamine 83057 29465 2.82 3% 3%
Azobenzene 33767 12258 2.75 3% 3%
2,4,6-Tribromophenol (surr5) 8112 2446 3.32 9% 9%
4-Bromophenylphenyl ether 46174 16368 2.82 2% 2%
Hexachlorobenzene 66655 23317 2.86 2% 2%
Phenanthrene 217071 75086 2.89 2% 2%
Anthracene 153651 56359 2.73 3% 3%
Di-n-butylphthalate 47057 22083 2.13 4% 4%
Fluoranthene 156372 58980 2.65 3% 2%
Pyrene 183429 66699 2.75 5% 2%
d14-Terphenyl (surr6) 124115 42921 2.89 3% 3%
Butylbenzylphthalate 5804 3208 1.81 4% 4%
3,3'-Dichlorobenzidine 7062 3683 1.92 6% 7%
Benzo(a)anthracene 82722 32431 2.55 6% 5%
Chrysene 190329 50968 3.73 4% 2%
bis(2ethylhexyl)phthalate 8024 4943 1.62 6% 4%
Di-n-octyl phthalate 9967 6055 1.65 2% 5%
Benzo(b)fluoranthene 28907 11587 2.49 5% 19%
Benzo(k)fluoranthene 85712 23457 3.65 4% 5%
Indeno(1,2,3-cd)pyrene 28327 11083 2.56 5% 9%
Dibenzo(a,h)anthracene 34104 12335 2.76 2% 6%
Benzo(g,h,i)perylene 73434 26528 2.77 2% 5%
Average 2.71 3.0% 3.5%
11
Conclusion
The system shows good performance for all compounds spec-ified by Method 8270 with regards to sensitivity and linearity.The calibration range used is well below what has been his-torically used by USEPA laboratories. The MassHunter datasystem brings added value and flexibility to routine analysiswhile providing visual indicators to supplement the numericalvalues typically used when indicating the pass/fail criteriadefined by Method 8270. Using the extractor lens and Etunetuning procedure offers superior performance and reliability.
For More Information
These data represent typical results. For more information onour products and services, visit our Web site atwww.agilent.com/chem.
www.agilent.com/chem
Agilent shall not be liable for errors contained herein or for incidental or consequentialdamages in connection with the furnishing, performance, or use of this material.
Information, descriptions, and specifications in this publication are subject to changewithout notice.