METHOD 8275 THERMAL CHROMATOGRAPHY/MASS SPECTROMETRY (TC/MS) FOR SCREENING SEMIVOLATILE ORGANIC COMPOUNDS

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1 METHOD 8275 THERMAL CHROMATOGRAPHY/MASS SPECTROMETRY (TC/MS) FOR SCREENING SEMIVOLATILE ORGANIC COMPOUNDS 1.0 SCOPE AND APPLICATION 1.1 Methd 8275 is a screening technique that may be used fr the qualitative identificatin f semivlatile rganic cmpunds in extracts prepared frm nnaqueus slid wastes and sils. It is nt intended fr use as a rigrus quantitative methd. Direct injectin f a sample may be used in limited applicatins. The fllwing analytes can be qualitatively determined by this methd: Cmpund Name CAS N. a 2-Chlrphenl Methylphenl ,4-Dichlrphenl Naphthalene Chlr-3-methylphenl Chlrnaphthalene ,4-Dinitrtluene Flurene Diphenylamine Hexachlrbenzene Dibenzthiphene Phenanthrene Carbazle Aldrin Pyrene Benz(k)fluranthene Benz(a)pyrene a Chemical Abstract Services Registry Number. 1.2 Methd 8275 can be used t qualitatively identify mst neutral, acidic, and basic rganic cmpunds that can be thermally desrbed frm a sample, and are capable f being eluted withut derivatizatin as sharp peaks frm a gas chrmatgraphic fused-silica capillary clumn cated with a slightly plar silicne. 1.3 This methd is restricted t use by r under the supervisin f analysts experienced in the use f gas chrmatgraph/mass spectrmeters and skilled in the interpretatin f mass spectra. Each analyst must demnstrate the ability t generate acceptable results with this methd. CD-ROM Revisin 0

2 2.0 SUMMARY OF METHOD 2.1 A prtin f the sample ( g) is weighed int a sample crucible. The crucible is placed in a pyrcell and heated. The cmpunds desrbed frm the sample are detected using a flame inizatin detectr (FID). The FID respnse is used t calculate the ptimal amunt f sample needed fr mass spectrmetry. A secnd sample is desrbed and the cmpunds are cndensed n the head f a fused silica capillary clumn. The clumn is heated using a temperature prgram, and the effluent frm the clumn is intrduced int the mass spectrmeter. 3.0 INTERFERENCES 3.1 Cntaminatin by carryver can ccur whenever lw-level samples are analyzed after high-level samples. Whenever an unusually cncentrated sample is encuntered, it shuld be fllwed by the analysis f an empty (clean) crucible t check fr crss cntaminatin. 4.0 APPARATUS AND MATERIALS 4.1 Thermal Chrmatgraph (TC) System TM Thermal chrmatgraph, Ruska Labratries, r equivalent Clumn - 30 m x 0.25 mm ID (r 0.32 mm ID), 1 µm film thickness, silicne-cated, fused-silica capillary clumn (J&W Scientific DB-5 r equivalent) Flame Inizatin detectr (FID). 4.2 Mass Spectrmeter (MS) system Mass Spectrmeter - Capable f scanning frm 35 t 500 amu every ne secnd r less, using 70 vlts (nminal) electrn energy in the electrn impact inizatin mde TC/MS interface - Any GC-t-MS interface prducing acceptable calibratin data in the cncentratin range f interest may be used Data System - A cmputer must be interfaced t the mass spectrmeter. The data system must allw the cntinuus acquisitin and strage n machine-readable media f all mass spectra btained thrughut the duratin f the chrmatgraphic prgram. The cmputer must have sftware that can search any GC/MS data file fr ins f a specific mass (r grup f masses) and that can plt such in abundances versus time r scan number. This type f plt is defined as an extracted in chrmatgram (EIC). Sftware must als be available that allws fr integratin f the abundances in, and EIC between, specified time r scannumber limits. CD-ROM Revisin 0

3 4.3 Tls and equipment Fused quartz spatula Fused quartz incineratr ladle Metal frceps fr sample crucible Sample crucible strage dishes Prus fused quartz sample crucibles with lids Sample crucible cleaning incineratr Cling rack Micrbalance, 1 g capacity, g sensitivity, Mettler Mdel M-3 r equivalent. 4.4 Vials - 10 ml, glass with Tefln lined screw-caps r crimp tps. 4.5 Vlumetric flasks, Class A - 10 ml t 1000 ml. 5.0 REAGENTS 5.1 Reagent grade inrganic chemicals shall be used in all tests. Unless therwise indicated, it is intended that all reagents shall cnfrm t the specificatins f the Cmmittee n Analytical Reagents f the American Chemical Sciety, where such specificatins are available. 5.2 Slvents Methanl, CH OH - Pesticide grade r equivalent Acetne, CH C0CH - Pesticide grade r equivalent Tluene, C H CH - Pesticide grade r equivalent Methylene chlride, CH Cl - Pesticide grade r equivalent Carbn disulfide, CS - Pesticide grade r equivalent Hexane, C H - Pesticide grade r equivalent Other suitable slvents - Pesticide grade r equivalent. 5.3 Stck Standard slutins - Standard slutins may be prepared frm pure standard materials r purchased as certified slutins Prepare stck standard slutins by weighing abut 0.01 g f pure material. Disslve the material in pesticide quality acetne, r CD-ROM Revisin 0

4 ther suitable slvent, and dilute t 10 ml in a vlumetric flask. Larger vlum es may be used at the cnvenience f the analyst Transfer the stck standard slutins int glass vials with Tefln lined screw-caps r crimp tps. Stre at -10EC t -20EC r less and prtect frm light. Stck standard slutins shuld be checked frequently fr signs f degradatin r evapratin, especially prir t use in preparatin f calibratin standards Stck standard slutins must be replaced after 1 year, r sner if cmparisn with quality cntrl check samples indicates a prblem. 5.4 Internal Standard slutins - The internal standards recmmended are 1,4-dichlrbenzene-d 4, naphalene-d 8, acenapthene-d 10, phenanthrene-d 10, chrysene-d, and perylene-d. Other cmpunds may be used as internal standards as lng as the requirements given in Sec. 7 are met. Disslve abut g f each cmpund with a small vlume f carbn disulfide. Transfer t a 50 ml vlumetric flask and dilute t vlume with methylene chlride, s that the final slvent is apprximately 20/80 (V/V) carbn disulfide/methylene chlride. Mst f the cmpunds are als sluble in small vlumes f methanl, acetne, r tluene, except fr perylene-d. Prir t each analysis, depsit abut 10 µl 12 f the internal standard nt the sample in the crucible. Stre internal standard slutins at 4 C r less befre, and between, use. 5.5 Calibratin standards - Prepare calibratin standards within the wrking range f the TC/MS system. Each standard shuld cntain each analyte r interest (e.g. sme r all f the cmpunds listed in Sec. 1.1 may be included). Each aliqut f calibratin standard shuld be spiked with internal standards prir t analysis. Stck slutins shuld be stred at -10 C t -20 C and shuld be freshly prepared nce a year, r sner if check standards indicate a prblem. The daily calibratin standard shuld be prepared weekly, and stred at 4 C. 6.0 SAMPLE COLLECTION, PRESERVATION, AND HANDLING 6.1 See the intrductry material t this Chapter, Organic Analytes, Sec PROCEDURE 7.1 Crucible Preparatin Turn n the incineratr and let it heat fr at least 10 minutes. The bre f the incineratr shuld be glwing red Lad the sample crucible and lid int the incineratr ladle and insert int the incineratr bre. Leave in the incineratr fr 5 minutes, then remve and place n the cling rack. CD-ROM Revisin 0

5 7.1.3 Allw the crucibles and lids t cl fr five minutes befre placing them in the strage dishes. CAUTION: D nt tuch the crucibles with yur fingers. This can result in a serius burn, as well as cntaminatin f the crucible. Always handle the sample crucibles and lids with frceps and tls specified All sample crucibles and lids required fr the number f analyses planned shuld be cleaned and placed in the strage dishes ready fr use. 7.2 Sample Preparatin and Lading The analyst shuld take care in selecting a sample fr analysis, since the sample size is generally limited t g r less. This implies that the sample shuld be mixed as thrughly as pssible befre taking an aliqut. Because the sample size is limited, the analyst may wish t analyze several aliquts fr determinatin The sample shuld be mixed r grund such that a t g aliqut can be remved. Remve ne sample crucible frm the strage dish and place it n the micrbalance. Establish the tare weight. Remve the sample crucible frm the balance with the frceps and place it n a clean surface Lad an amunt f sample int the sample crucible using the fused quartz spatula. Place the assembly n the micrbalance and determine the weight f the sample. Fr severely cntaminated samples, less than g will suffice, while g is needed fr lw cncentratins f cntaminants. Place the crucible lid n the crucible; the sample is nw ready fr analysis. 7.3 FID Analysis Lad the sample int the TC. Hld the sample at 30 C fr 2 minutes fllwed by linear temperature prgrammed heating t 260 C at 30 C/minute. Fllw the temperature prgram with an isthermal heating perid f 10 minutes at 260 C, fllwed by cling back t 30 C. The ttal analysis cycle time is 24.2 minutes Mnitr the FID respnse in real time during analysis, and nte the highest respnse in millivlts (mv). Use this infrmatin t determine the prper weight f sample needed fr cmbined thermal extractin/gas chrmatgraphy/mass spectrmetry. 7.4 Thermal Extractin/GC/MS Prepare a calibratin curve using a clean crucible and lid by spiking the cmpunds f interest at five cncentratins int the crucible and applying the internal standards t the crucible lid. Analyze these standards and establish respnse factrs at different cncentratins. CD-ROM Revisin 0

6 7.4.2 Weigh ut the amunt f fresh sample that will prvide apprximately 1000 t 3000 mv respnse. Fr example, if g f sample gives an FID respnse f 500 mv, then t g (0.040 g ± 50 %) shuld be used. If g gives 8000 mv, then g ± 50 % shuld be used After weighing ut the sample int the crucible, depsit the internal standards (10 µl) nt the sample. Lad the crucible int the pyrcell, using the same temperature prgram in Sec Hld the capillary at 5 C during this time t fcus the released semivlatiles (the intermediate trap is held at 330 C t pass all cmpunds nt the clumn). Maintain the splitter zne at 310 C, and the GC/MS transfer line at 285 C. After the isthermal heating perid is cmplete, temperature prgram the clumn frm 5 C t 285 C at 10 C/minute and hld at 285 C fr 5 minutes. Acquire data during the entire run time If the respnse fr any quantitatin in exceeds the initial calibratin curve range f the TC/MS system, a smaller sample shuld be analyzed. 7.5 Data Interpretatin Qualitative Analysis The qualitative identificatin f cmpunds determined by this methd is based n retentin time, and n cmparisn f the sample mass spectrum, after backgrund crrectin, with characteristic ins in a reference mass spectrum. The reference mass spectrum must be generated by the labratry using the cnditins f this methd. The characteristic ins frm the reference mass spectrum are defined t be the three ins f greatest relative intensity, r any ins ver 30% relative intensity if less than three such ins ccur in the reference spectrum. Cmpunds shuld be identified as present when the criteria belw are met The intensities f the characteristic ins f a cmpund maximize in the same scan r within ne scan f each ther. Selectin f a peak by a data system target cmpund search rutine where the search is based n the presence f a target chrmatgraphic peak cntaining ins specific fr the target cmpund at a cmpund-specific retentin time will be accepted as meeting this criterin The RRT f the sample cmpnent is within ± 0.06 RRT units f the RRT f the standard cmpnent The relative intensities f the characteristic ins agree within 30% f the relative intensities f these ins in the reference spectrum. (Example: Fr an in with an abundance f 50% in the reference spectrum, the crrespnding abundance in a sample spectrum can range between 20% and 80%.) CD-ROM Revisin 0

7 Structural ismers that prduce very similar mass spectra shuld be identified as individual ismers if they have sufficiently different GC retentin times. Sufficient GC reslutin is achieved if the height f the valley between tw ismer peaks is less than 25% f the sum f the tw peak heights. Otherwise, structural ismers are identified as ismeric pairs Identificatin is hampered when sample cmpnents are nt reslved chrmatgraphically and prduce mass spectra cntaining ins cntributing by mre than ne analyte. When gas chrmatgraphic peaks bviusly represent mre than ne sample cmpnent (i.e., a bradened peak with shulder(s) r a valley between tw r mre maxima), apprpriate selectin f analyte spectra and backgrund spectra is imprtant. Examinatin f extracted in current prfiles f apprpriate ins can aid in the selectin f spectra, and in qualitative identificatin f cmpunds. When analytes celute (i.e., nly ne chrmatgraphic peak is apparent), the identificatin criteria can be met, but each analyte spectrum will cntain extraneus ins cntributed by the celuting cmpund Fr samples cntaining cmpnents nt assciated with the calibratin standards, a library search may be made fr the purpse f tentative identificatin. The necessity t perfrm this type f identificatin will be determined by the purpse f the analyses being cnducted. Cmputer generated library search rutines shuld nt use nrmalizatin rutines that wuld misrepresent the library r unknwn spectra when cmpared t each ther. Fr example, the RCRA permit r waste delisting requirements may require the reprting f nn-target analytes. Only after visual cmparisn f sample spectra with the nearest library searches will the mass spectral interpretatin specialist assign a tentative identificatin. Guidelines fr making tentative identificatin are: (1) Relative intensities f majr ins in the reference spectrum (ins > 10% f the mst abundant in) shuld be present in the sample spectrum. (2) The relative intensities f the majr ins shuld agree within + 20%. (Example: Fr an in with an abundance f 50% in the standard spectrum, the crrespnding sample in abundance must be within 30 and 70%). (3) Mlecular ins present in the reference spectrum shuld be present in the sample spectrum. (4) Ins present in the sample spectrum but nt in the reference spectrum shuld be reviewed fr pssible backgrund cntaminatin r presence f celuting cmpunds. CD-ROM Revisin 0

8 8.0 QUALITY CONTROL (5) Ins present in the reference spectrum but nt in the sample spectrum shuld be reviewed fr pssible subtractin frm the sample spectrum because f backgrund cntaminatin r celuting. Data system library reductin prgrams can smetimes create these discrepancies. 8.1 Refer t Chapter One and Methd 8000 fr specific quality cntrl prcedures. 9.0 METHOD PERFORMANCE 9.1 Table 1 presents methd perfrmance data, generated using spiked sil samples. Methd perfrmance data in an aqueus matrix are nt available REFERENCES 1. Zumberge, J.E., C. Suttn, R.D. Wrden, T. Junk, T.R. Irvin, C.B. Henry, V. Shirley, and E.B. Overtn, "Determinatin f Semi-Vlatile Organic Pllutants in Sils by Thermal Chrmatgraphy-Mass Spectrmetry (TC/MS): an Assessment fr Field Analysis," in preparatin. CD-ROM Revisin 0

9 TABLE 1 METHOD PERFORMANCE, SOIL MATRIX a Average % Recvery Mean Analyte Clay Silt Subsil Recvery 2-Chlrphenl Methylphenl ,4-Dichlrphenl Naphthalene Chlr-3-methyl-phenl Chlrnaphthalene ,4-Dinitrtluene Flurene Diphenylamine Hexachlrbenzene Dibenzthiphene Phenanthrene Carbazle Aldrin Pyrene Benz(k)fluranthene Benz(a)pyrene a Percent theretical recvery based upn linearity f injectins depsited n the crucible lid (slpe and y-intercept). Average f 9 replicates (~10 mg sil spiked with 50 ppm f analyte); 3 different instruments at 3 different labratries. CD-ROM Revisin 0

10 TABLE 2 CHARACTERISTIC IONS FOR SEMIVOLATILE COMPOUNDS Primary Secndary Cmpund In In(s) 2-Chlrphenl ,130 4-Methylphenl ,108,77,79,90 2,4-Dichlrphenl ,98 Naphthalene ,127 4-Chlr-3-methyl-phenl ,142 1-Chlrnaphthalene ,164 2,4-Dinitrtluene ,89 Flurene ,167 Diphenylamine ,167 Hexachlrbenzene ,249 Phenanthrene ,176 Aldrin ,220 Pyrene ,203 Benz(k)fluranthene ,125 Benz(a)pyrene ,125 CD-ROM Revisin 0

11 METHOD 8275 THERMAL CHROMATOGRAPHY/MASS SPECTROMETRY (TC/MS) FOR SCREENING SEMIVOLATILE ORGANIC COMPOUNDS CD-ROM Revisin 0