GC/MS Analysis (Semi-Volatiles)
(Method 8270C)
Description
Method 8270C(SW-846) is used to determine Semi-Volatile organic components in a variety of matrices. (See SOP #6010, 6020 for preparatory information) Generally, this method is applied to RCRA site assessments and hazardous waste determinations. These methods are applicable to nearly all types of samples, including sludges, oily wastes, soils, sediments, extracts and waters.
Semi-Volatile components are introduced into the GC by direct injection post solvent extraction or dilution. The GC is temperature programmed to allow a narrow bore capillary column to separate the compounds, which are measured, via a quadruple mass spectrometer (MS).
Method sensitivity varies by matrix. The estimated quantitation limits on average are 0.5 mg/Kg (wet weight) for soils, 1-200mg/Kg (wet weight) for wastes and 10 mg/L for waters and extracts.
Precautions
Compressed gases (see procedure 0040)
Corrosive (see procedure 0020)
General Requirements (see procedure 0010)
Solvents (see procedure 0030)
Sample Preservation and Preparation:
Samples to be analyzed for semi-volatiles must be collected in a glass container with a Teflon-lined lid. Samples for semi-volatiles must be transported and retained under refrigeration at 4°C. Soil samples may be held for 14 days under refrigeration. Aqueous samples may be held for 7 days prior to extraction and 40 days prior to analysis. Store the sample extracts at –10°C, protected from light, in sealed vials.
Interferences
Interferences can exist as a result of poor extraction techniques, contaminated reagents and instrumentation cleanliness. All glassware associated with the extraction and concentration processes must be thoroughly cleaned and oven baked prior to use. Caution must be taken to avoid any plastic sample or reagent containers to avoid possible phthalate contamination. A rigorous preventative maintenance routine is mandatory to maintain instrument performance.
Apparatus and Materials
-Mass Spectrometer: HP 5973 Quadrapole, 6890 GC, 7683 ALS
-Column: RTX-5ms, 30M, 0.25mmID and 0.5mm film thickness
-Gas Chromatograph: HP 6890, with 7683 AutoSampler
-GC/MS interface: Direct coupling of column to mass spectrometer
-Data System: HP Chemstation 1701B
-10mL syringes
Reagents and Standards
-Methylene Chloride
Sodium Hydroxide, pellets
Sulfuric Acid, concentrated
-Standards are purchased as certified solutions
-Surrogates: (Spiked prior to extraction procedure)
§ Nitrobenzene-d5 100mg/mL
§ 2-Fluorobiphenyl 100mg/mL
§ Terphenyl-d14 100mg/mL
§ Phenol-d6 200mg/mL
§ 2-Fluorophenol 200mg/mL
§ 2,4,6- Tribromphenol 200mg/mL
-Internal Standards: Prepare standard from purchased stock
Prior to injection a 1mL extract is spiked with 10mL of a 4000
spiked with 10mL of a standard resulting in 40mg/mL of:
§ 1,4-Dichlorobenzene-d4
§ Naphthalene-d8
§ Acenaphthene-d10
§ Phenanthrene-d10
§ Chrysene-d12
§ Perylene-d12
-DFTPP Standard: Prepare standard from purchased stock by diluting 1.0mL of
1.0mg/mL with MeCl2 to 20mL.
50mg/mL in Methylene Chloride is used as tuning standard. 1.0mL is injected.
-Calibration Standards: Calibration standards at a minimum five
concentration levels are prepared. One standard must be at or near, but above the method detection limit. Calibration standards are prepared weekly as required and are spiked with 10mL of I.S.
-Prepare calibration standards from purchased stock of 2000mg/mL by diluting
1.0mL to 10mL in MeCl2 to deliver 200mg/L secondary stock solution.
Table I provides dilution details for the following calibration standards:
F-Scan
TCLP Herbicides and/or Pesticides
Base Neutral
Acid
Benzidines
PAH’s
437 Additional Compounds
-Matrix Spike Standard: Matrix Spike compounds are spiked prior to extraction
include:
Phenol 200mg/mL 1,2,4-Trichlorobenzene 100mg/mL
2-Chlorophenol 200mg/mL Acenaphthene 100mg/mL
4-Methyl-3-Chlorophenol 200mg/mL 2,4-Dinitrotoluene 100mg/mL
4-Nitrophenol 200mg/mL Pyrene 100mg/mL
Pentachlorophenol 200mg/mL N-Nitrosodi-n-Propylamine 100mg/mL
1,4-Dichlorobenzene 100mg/mL
Di-n-Butylphthate 100mg/mL
-MS Tune Standard –Prepare from purchased stock by diluting 1.0mL of
1.0mg/mL with MeCl2 to 20mL. The standard will contain 50mg/mL of:
§ Benzidine
§ DFTPP
§ 4,4-DDT
§ Pentachlorophenol
1.0mL is injected.
-Laboratory Control Sample (LCS). Matrix spiking standard is used for LCS
-SPCC Standard – See calibration standard 50mg/L
-CCC Standard – See calibration standard 50mg/L
Note: All standards are stored at –10°C to –20°C in amber bottles with Teflon-
lined screw caps. All stock standards are stable for one year.
Procedure
1.0 Initial Calibration
1.1 Perform required preventative maintenance including injector liner, septa and guard column replacement or cleaning.
1.2 Check MS for leaks under autotune, if OK put PTA on and check mass calibrations. Recalibrate as necessary.
1.2.1 Set the operating conditions of the GC/MS as follows
Mass Range 35-500amu
Scan Time 1 sec/scan
Source Temperature 225°C
Injector Temperature 250°C
Transfer Line Temperature 280°C
Carrier Gas Helium at 30cm/second
1.3 Check MS tune by injecting 1.0mL of a 50mg/mL DFTPP standard. If conditions pass QC acceptance criteria go to next step, otherwise repeat step 1.3 until pass. See Table II and VI for specifications and instrument operating conditions.
1.4 Inject system performance check compounds (SPCC) to ensure the minimum average RF is met. See Table III and VI.
1.5 Run calibration standards at a minimum of five different concentrations. The resulting % RSD should be < 15%. See Table IV.
1.5.1 In addition, the % RSD for each calibration check compound (CCC) should be <30% (see Table V). The relative RT of each compound in each calibration run should agree within 0.06 minutes.
2.0 Daily Calibration/Quality Control
2.1 Perform required preventative maintenance checks including replacement and cleaning of injector liner, septa and guard column.
2.2 Run DFTPP/MS tune, establish QC acceptance. (See Table II and VI)
2.3 Analyze mid level calibration check standard (50mg/mL) and surrogates (200mg/mL). Compare instrument RF with SPCC and CCC acceptance criteria. (see Tables III and V).
2.4 Compare CCC compounds for % drift. If % difference for each compound is <20% calibration curve is validated. If the CCC analytes are not included in the calibration list, subject the entire compound list to the required drift criteria (ex. TCLP).
2.5 Check I.S. for chance in RT and EICP area. RT should not change by more than 30 seconds and EICP area should not change more than a factor of two (-50% +100%) from the last initial calibration check.
2.6 A method blank is to be analyzed for each extraction batch prior to any sample analysis and should reflect the matrix and analytical conditions of the samples to be analyzed. Blanks are analyzed to ensure the cleanliness of the entire analytical system and to guard against false positive results. If any compound of interest is identified in the blank, corrective action such as reanalysis, reextraction or instrument blanks should be employed. If the contamination cannot be eliminated, then all positive results from that batch should reported to the client with a “B” flag on the report.
2.7 A Laboratory Control Sample, essentially a blank spike, should be analyzed prior to any sample analysis. This should consist of at least the compounds listed in matrix spike table above but may contain all analytes of interest. The LCS is judged against spike recovery data for each compound.
2.8 One sample from each batch should be chosen for matrix spiking. The matrix spike should be done in duplicate. The MS/MSD are judged against spike recovery data for each compound, as well as relative percent deviation to measure precision and accuracy.
2.9 Sample duplicates can also be employed when results are questionable. (From carry-over contamination, etc.) If a matrix spike is not feasible (limited sample volume, for example), a sample duplicate and/or a LCS duplicate can be used for data validation.
3.0 Sample Analysis
3.1 Spike 1mL of the sample extract with 10mL of IS solution prior to analysis.
3.2 Inject 1mL of extract into GC/MS. (See Table VI)
3.3 If any sample analysis yields a result greater then the highest concentration of the initial calibration curve, then the sample should be diluted to bring the results to the upper half of the calibration curve. Detection limits also get the dilution factor applied to them on the report. Since surrogates are fixed prior to extraction, a high dilution factor may eliminate them. If so, they should be reported as diluted out on the report.September 9, 2007
4.0 Data Analysis
4.1 Each sample inject is reviewed and quantitated against the surrogate and calibration libraries
4.2 The concentration of analyte and surrogate compounds are calculated and recorded. Surrogate recoveries must be compared to acceptability criteria. (See Table VIII)
4.3 If response to any quantitation is greater than the initial calibration curve extract dilution and reanalysis will be required.
5.0 Batch Acceptance Criteria
5.1 All parameter detailed in the initial calibration (section 1.0-1.5) and daily calibration/quality control (section 2.0-2.5) must be met.
5.2 In addition to the instrument performance outlined in the previous step, the batch QC parameters for spike/spike duplicate and sample duplicates must be evaluated. The current acceptable limits are presented in Table VII and attachment 0140.
6.0 Reporting of Results
6.1 All results for QC parameters and samples are reported on the batch list.
6.1.1 All results are reported to three significant figures.
6.2 Analytical results generated from the GC/MS software report ppb (mg/L). All results require correction for preparatory or analytical dilutions. Dilution factors must be recorded in the preparation log and on the raw data printout. All reportable data must fall within the calibration curve post dilution.
7.0 Calculations
7.1 For Water Samples
Concentration (mg/L) = {[(A)(B)]/[(C)(D)(E)]} * Dilution Factor
7.2 For Soil Samples
Concentration (mg/Kg) = {[(A)(B)(F)]/[(C)(D)(G)(H)(I)]} * Dilution Factor
7.3 Definition of Variables
§ A = Area of characteristic ion for compound being tested
§ B = Amount of internal standard injected (ng)
§ C = Area of characteristic ion for the internal standard
§ D = Mean relative response factor for the compound being measured
§ E = Volume of water purged (mL) taking into consideration any dilution made
§ F = Volume of total extract (mg/L) (used 10,000mg/L or a factor of this when dilutions are made.)
§ G = Volume of extract added (mg/L) for purging
§ H = Weight of sample extracted or purged (g)
§ I = % dry weight of sample/100, or 1 for a wet-weight basis
7.4 Record instrument performance QC data on the daily validation report sheet. File all raw data along with completed form by date of analysis.
Quality Control
· Initial Calibration parameters must be met after major maintenance, failed QC
or yearly
· A daily check is required of the MS tune, SPCC and CCC compounds to validate calibration. The standard checks must be run every 12 hours.
· Each analytical batch analyzed for semi-volatiles must be accompanied by a blank and a blank spike consisting of ultra-pure water or sand taken through all analytical steps.
· All weights, volumes, comments, etc. for each batch must be entered in notebook form for data review.
· As determined by notebook order, every 10th sample of similar matrix shall be analyzed in duplicate; every 20th sample shall be analyzed as a duplicate spike. (Calculations for RPD and % Recoveries must be calculated for each parameter, see procedure 0110 for calculations)
· A laboratory control sample (LCS) must be analyzed per batch of 20 samples of the same matrix
· Required recoveries for duplicate and spike duplicate recoveries shall be determined using historical data. The current acceptable limits for the parameters are listed in procedure 0140 and Table VIII.
· Failure to meet quality control acceptable limits requires corrective action (see procedure 0150). Require, locate, and correct the source of the problem and repeat the test. Failure to meet the quality control acceptable limits again will require new calibration curve
· All reported sample results must be checked for internal standard and surrogate recovery. A failed recovery should be reanalyzed to confirm, and reported as matrix interference if confirmed.
References:
SW 846 Method 8270C-1 to 8270C-54
Revision 3 December 1996
40 CFR PT 136 App. A Method 625 pp. 204-231
Revised July 1, 199
11
Procedure 6600
Revised 04/07