Document v1X0Mb7jk0x97k2yk16yxJMnR

v*a b l> Van *4-^ ij Interoffice Communication to P. L. Feteer from K. L. Kachett Date subject August IS, 1975 Evaluation of Bendix Flasher for Ambient Air Analysis Sll*fA ia" A UP CGnCLUGIChS: Good results were obtained for vinyl chloride but more work would ba required to demonstrate a satisfactory analysis for the higher boiling iratfcrials such as ethylsac dichloride. Use of temperatures above 2GQ"'C to spaed vaporisation into the chromatograph column lead to cracking of ethyl ana dichloride and ethyl chloride with subsequent above theoretical reccvru.7/ of vinyl. chloride*. Considerable mechanical problems with leaks were encountered especially around the tube seals. It is recommended that the bondix Flash2r Unit bo purchased for monitoring where vinyl chloric:-;; exposure is the only concern. r*rr r^CriTvyT-T: Tile Tendi;: Flasher is basically a small tuba furnace, tejnpcr-.cure controlled, for vaporisation of components absorbed on charcoal into the inlet card or quo stream of a g.;.? chromatograph. Current cost of the instrument i.s -9795. Several advantages arc claimed for tin unit ever conventional solvent desorption/gas chromatography methods of analysis of ambient air samples. 1. }Jo solvent is used which eliminates interferring peaks ana the weighing ax:u handling of hazardous liquids. 2, The entire amount of components from the air volume sampled is injected into the gas chromatograph. Thun the volume of air sampled and the amount of charcoal used can be smaller witiiout exceeding its capacity and still give good sensitivity. With the Bendiz Flasher system ambient air is drawn through a 3 i i inch f I -T -:l v + V " ,-v-v. /- /- . i~i |T-,+ V, .-v< p `I **- j.cu enureoal is r.-seoarmeuaed and suppliau by i.,e.nuix for lAiis jjurposo. V.'hua I.. ;:n-plG as h .:.t eolliot;d at placed 'a. tie 'Tlashar" . A hinge a scaling r/euhunism isolates* the tube inside the hjcco.j ;x.lvca of the tube furnace between two solenoid wilvtvf. Two minutes nre allowed for the tube no corn to tic.' set tejperasarc th.vi the injocu ."witch s energized manna.liy. This r ./itches the (normally by-passcd) carrier gcfj flc.v through the v. ample loop ja.to the chromatograph. nr-* - - - v^-'f, last of Lhe current v.-ork with lha stain Flasher involv eu a comp..!*'con rf the* relative peak areas of a standard pm;? mixuur0 (50-55 ppm each of YU.l, AtCl, ana ADA* in nitrogen) vaporised fvc-n sample 1 ubea with -a' t-r' k & i i\.r.i u..e u^ea vOJ.Ui.ie .Si^ --cmOu uereCv..^ .<.*.wvj VVC 000010889 z :rr.ur n, -j- Thrav principal rc.tl.0J3 or irndifienticno vrere investigated. ?rr;T^t 1 - -be or pop .td >-:->-ry. edified ciiapcpatr - vath pcb i?. j: 30 mesh charcoal in tubco and a tube furnace temperature of ?,,3jC essentially IDO percent recoveries of vinyl chloride end ethyl chloride were obtained cut only 50 percent recovery of ethylene diehloriue y*l) A3 rrhcv.n in Graph 1, increasing the furnace temperature uo 2BCC cave- V utter EDO recovery, 73.V percent, but care cracking leading to above theoretical recovery of vinyl chloride. Clicking (d c byurei.a 1cgl-r..atior.) of both EEC and ethyl chloric: was extensive at 250C. Thus, the Bcndix Flasher using PCS charcoal appears to work satisfactorily for VCM and relatively losr boiling compounds such as ethyl chloride, but not for ADC. 1. Results reported were obtained using a 6 foot x Porapak Q, Column in a Eendix gas chromatograph at the Chemical riant Laboratory. rT\h. re '-.ed,, iOfieOdu cCir',,*.orccal supplied and recommended by bendix was difficult to ccoonnddittion ((ryeammoo*ve small amounts of absorbed interferring compounds) and did not give ;sharp : ?at;:dd x: - uo L suggested to re; via L:XT. !1"7*7 r *9 poly:---. Good peio.T-ure was not too high fea. 220C optimum) but results for VCDS arid ethyl chloride were low ns shown in Table I. IfBXHQD TTT USE 0? PPM ZCVL AD30R??Tl?h TUBBS. - Since the lew results for Yd or.a ethyl crJ.ori.dc above night bo one to incomplete retention of these components on the XC.'AX a dual zone tube was tried. These tubes were filled approximately half full vrith FOB charcoal and the rest cf the* way v/ith IId AX, Both the view introduction to, and"elution from, the sample tube were at the YHtX end. The purpose of the charcoal fcas to trap any components not com pletely absorbed in the polymer. This procedure resulted in poorly resolved end toiling vinyl chloride ana ethyl chloride peaks. Recovery data were erratic and inconclusive frem these trials. -a.JV ^ K. L, Pickett nn , JAD, DIM, CDP, JT, JSR VVC Q0Q010390 TUBE FACKIIIG- TEKAX TENAX TEUAX TEI/tf/PCB^ TI2:Aa/FC3^ TAELS I USE OF TiXAX AND i-s:ax/pcb saj.IFLE TUBES FLASHER TC.r?SR/uuRE o C ISO 220 250 ISO 220 vci.i 57.7 7S.0 134 SO.8 125 L,it 01 86.1 63 79.6 101.3 tr. EDO 87.7 124.1 54.8 89.3 58.4 (1) Tailing Gj'd incc-plc-t'ily rwjolvad YCY and EiCl peaks We 000l a9l {Vo o IffO --4 - /1 o G /6 7w 6 - _*** 7:7: 7* *7 :r:"i -73 * ^ * ............ 3 7rC 77:77: :::: I fa n/M :: /--CH::^ WC-OA K;: H 7 3:/?r,\fe/s .4;-- r:/~. {%'.r.i-- l-~ '^:: vr-r-i..::::;. /?77lj77~ ::7777777H ''Q\i~. ---~r/^jg^r/r^rtfn----' -- :-r;j;:::?rj--::;r. 771 '^ - ---i )S,0 aa /*/0 '. 4 uo a nI- o. o Z< \ s* 3 u f-\-J1A1C? r.:_4 f::: il --1--. -4----( - T7rj77 --------- +--* ------- -4 -- 4------- *- . 1 v"-7-^7-77~ H-k--- --i,,..-- Pi to k Sc l 6 Cj k^ $9 a *T ^v ft * oZ cl za "n ua N I- Li N 7C -rr~'" I ; ;7737t77l37:77TjH- :-j:r.r Trrrr^zrr 1: 373433 - ;X.~ \- -1 ::7 :: --+- jro (i. ^ a d Vi .:r . 4::; -!-:: 1 H- 1- 3.P- 7'773T;:r:1::': 773 ... .-v- 3--3IP3H : :j 77;37737:~ .. 1 ... 1. ::j: . . ..j . . . . 1 . 1 . liiikiiiiiiliLli 3:337 . ......... .. , , +--t , , *_. :Tl:iHkMT4-kkrHT ;!" 14 Tf::::::: VVC 000010892 :-T i::i;:':!][:: BENDIX HS-10 FLASHER AND PERSONNEL MONITORING SYSTEM A SUMMARY REPORT OF CURRENT DATA BENDIX PROCESS INSTRUMENTS DIVISION LEW1SBURG, WEST VIRGINIA 304 647-4358 JESSE C. PATTON, Ph.D. PRODUCT MANAGER, ENVIRONMENTAL AND HEALTH/SAFETY PRODUCTS FEBRUARY 25, 1975 VVC 000010393 I TABLE OF CONTENTS PAGE I. SAMPLING TECHNIQUES .............................................................................................. 1 A. Bendix Personnel Monitoring Collection Column (PMCC).......................... 1 B. Bendix PMCC and Micronair Pump ...................................................................... 1 1. Test Methodology ................... ......................................................................... 1 2. Sampling Performance Data ........................................................................... 2 C. Bendix PMCC and Longer Life Pumps.................................................................. 3 II. PMCC RETENTION OF VINYL CHLORIDE DURINGSAMPLING...................... 3 A. Break-through Test Methodology.......................................... ................................ 3 B. Break-through Test Data........................................................................................... III. BENDIX FLASHER ANALYTICAL TECHNIQUE FORVCL..................................... 4 A. Reproducibility of PMCC-to-PMCC ............................................................... .. 4 1. Test Methodology .............................................................................................. 4 2. Reproducibility Data of VC I PMCC-to-PMCC ...................................... 5 B. Linearity with the Bendix Flasher ........................................................................ 5 1. Test Methodology ............................................................................................. 5 2. Linearity Test Data ............................................................................................ 5 C. Sensitivity with the Bendix Flasher and FID Detector ................................. 6 1. Test Data ............................................................................................................ 6 2. Theory and Projected FID Sensitivity .............. ............................. .. 6 IV. VINYL CHLORIDE SAMPLE DIE-OUT ON STORED PMCC TUBES ................ 7 V. BENDIX PMCC-FLASHER TECHNIQUE FOR OTHER INDUSTRIAL VAPORS . 7 TABLE I Low Pump Rate Data .................................................................................................... 8 TABLE II STAT on 4.0 hr (Initial) Performance (cc/min Data) ...................................... 9 TABLE ill STAT on 7 hr-40 min Performance (cc/min data)............................................ 10 TABLE IV PMCC Vinyl Chloride Breakthrough Data ........................................................ 11 01089* VMC 000 TABLE OF CONTENTS, Continued PAGE TABLE V Extreme Ambient Sampling Conditions .......................... ....................................... 11 TABLE VI VINYL CHLORIDE RECOVERY FROM STORED PMCC'S .......................... 12 TABLE VII OS HA Specified Vapors .................................................................. ..................... 13 FIGURE I .................................................................................................................. 2 FIGURE 2 ............................................................................................................................................. 4 FIGURE 3 ............................................................................................................................................. 14 FIGURE 4............................................................................................................................................. 15 FIGURE 5 .................................................................................................................... 16 VVC 0000X0895 SAMPLING TECHNIQUES A, Bendix Personnel Monitoring Collection Column (PMCC). The Bendix PMCC modified charcoal* Is the best packing material we have found for use as a collection medium for organic industrial type vapors. This packing allows long sampling times (greater than 24 hours in selected cases) for VCl and other vapors. This packing also allows the collected vapors to be quickly thermally desorbed at reasonable temperatures, e.g., 200-300C., thereby eliminating the possibility of thermal degradation of most vapors during analysis. The percent desorption of VCl from the PMCC is greater than 98%. Equal concen trations of VCl, which were loaded onto both Bendix modified charcoal and Porapak Q, when thermally desorbed gave identical responses. Since Porapak Q is known to desorb greater than 98% of its trapped organic vapors, it is reasonable to assume the Bendix modified charcoal also desorbs greater than 98% of its VCl. Also, the excellent linearity curve shown in Fig. 3 supports the conclusion that thermally desorption is essentially 100%. B. Bendix PMCC and Micronair Pump 1. Test Methodology For time-weighted averaged samples it is generally best to operate the sample pump and PMCC at low flow rates (10 cc/min or less). In an effort to test the performance of the Bendix Micronair pump and PMCC at low flow rates (2 cc/min) this sampling system was allowed to operate in an uninterrupted manner for nearly eight (8) hours. Flow rates were periodically checked with a bubble meter and stop watch. (Figure 1) *Bendix modified charcoal is proprietary information. Patent pending. 1 VVC 000010896 2 BUBBLE METER 2. Sampling Performance Data Detailed sampling data are shown in Tables I and ill. Summarized data are presented below* FOUR-HOUR PERFORMANCE DATA Average flow rate ..................................................................................... 1.79 cc/min Average deviation from the mean...................................................... 0.007 cc/min Standard deviation {O') .................................................................... 0.04 Percent average variation .................................................................... 1 .64% SEVEN-HOUR FORTY-MINUTE PERFORMANCE DATA Average flow rate .................................................................................... 1.77 cc/min Average deviation from the mean................................. 0.01 cc/min Standard deviation {O')......................................................................... 0.06 Percent average variation .................................................................... 2.88% VVC 000010897 3 C. Bendix PMCC and Longer Life Pumps While theMicronair pump data presented above is adequate for 4-8 hour personnel monitoring, it is recognized that this pump is not capable of performing for longer periods of time without recharging the battery. The Sipin pump was found to be comparable to the Bendix Micronair. For sampling times of twenty four hours or more in a stationary mode, the line operated pumps are feasible. II. PMCC RETENTION OF VINYL CHLORIDE DURING SAMPLING A. Break-through Test Methodology Sampling retention data was obtained by placing the PMCC in series with a VCl cylinder and Flame Ionization Detector (FID) at 32C and 25C, Special tests to determine the effect of water vapor were conducted by passing the VCl through a water bath prior to the PMCC. Flow rates through the PMCC were determined with a bubble meter. A positive change in FID response indicated VCl breakthrough had occurred. Both sample rates and sample concentrations were varied during these tests. (Figure 2) B. Most of our breakthrough data are summarized in Tables IV and V. Three factors appear to control VCl sample breakthrough volumes. They are: 1 . Sample Concentration 2. Sample Flow Rate 3. Humidity Extreme temperature and humidity (32C, 95% R.H.) tests with a 40-ppm VCl sample (A> 5 cc/min flow rate gave no breakthrough after 55 hours. M\/C 4 gas sample of KNOWN PPM VCI FIG. 2 HI. BEND1X FLASHER ANALYTICAL TECHNIQUE FOR VCL A. Reproducibility of PMCC-to-PMCC 1. Test Methodology For this test thirty-six (36) individual PMCC tubes were loaded with 150 cc of an uncertified sample of 10 PPM Vinyl Chloride over a period of 4 hours. The PMCC's were analyzed in batches of twelve (12) during a 48-hour period with the following equipment and parameters: EQUIPMENT: Bendix 2500 G.C. 350 VDC FID Bendix Flasher Temp. 250C 4 ft. X 1/8 in. Porapak Q 60/80 Column @ 100C Electrometer 2 X 10"^ afs Heat Time2 min 0-10mv Recorder and Autolab 6300 Integrator 000010099 VVC 2. Reproducibil ity Data of VCI PMCC STAT BATCH JP-716A BATCH JP-716B BATCH JP-716C Ave. Count* 17600 19200 18400 % Ave. Var. 3.5% 2.1% 1.6% % Max. Var. 9.7% 5.7% 4.3% 95% Conf'd (2o) 16 10.2 8.4 Std. Dev. (o) 7.9 5.1 4.2 *FID Detector Response by Integrator Count XI0"^ 0 u1 % Q. 5 BATCH JP-716A- B-C 18400 2.4% 9.2% 11.6 5.8 B. Linearity with the Bendix Flasher 1. Test Methodology In a typical test a PMCC was loaded with different volumes of a 10-PPM Vinyl Chloride sample from a premixed gas cylinder of VCI. Sample volumes varied from 50 cc to 10,000 cc. Sample rates varied from 50 cc/min to 1,000 cc/min. The samples were thermally desorbed at 250C with the Flasher into a 6 ft X 1/8 in. Porapak Q 60/80 mesh analytical column with a 100C Isothermal oven tempera ture. Sample response to a flame ionization detector was determined with an Autolab 6300 digital integrator and 0-1 Omv strip chart recorder. 2. Linearity Test Data The linearity curve shown in Figure 3 was obtained by plotting integratordetector response versus VCI sample volume. Good linearity was observed over the entire sample range. More data are needed for the low partsper-billion (PPB) range both for linearity as well as sensitivity studies. VVC 000010900 6 These data are contingent upon arrival of low VCI permeation wafers from Metronics, Inc. The good linearity plot also indicates that essentially all the Vinyl Chloride is thermally desorbed from the PMCC tubes. This opinion has been fortified by observing that similar tubes packed with porous polymers and loaded with equal volumes (100 cc) of 10-PPM VCI gave the same detector response as the Bendix modified charcoal. C. Sensitivity with the Bendix Flasher and FID Detector 1. Test Data Test data indicates excellent sensitivity at the 1-10 PPM range. For example, a 150 cc sample of 10 PPM Vinyl Chloride gives Ca. 50% full scale response on a 0-1 Omv chart recorder at an electrometer setting of 2 X 10"^ afs. The same sample gives an integrator count of approxi mately 18000 counts on a autolab digital integrator (cite III.A.2.). Theory predicts excellent sensitivity in the low ppb range which is discussed below. 2. Theory and Projected FID Sensitivity The combination of the PMCC sampling technique and Flasher thermal desorption technique offers a potential analytical method capacity for monitoring 1 PPB or less of Vinyl Chloride. The ability of the PMCC packing to retain VCI and other organic vapors from large volumes (>10-^ of ambient air offers an excellent means for concentrating these vapors. Furthermore, since the Flasher thermal desorption technique requires no solvent desorption, and consequently no sample dilution, the entire concentrated sample is available for analysis. For example, a 10-liter sample of 1 PPB VCI could provide 0.25 j^g o0ooio901 7 (250 ng) to the detector which is well within the sensitivity limits of a FID detector. Compared with the carbon disulfide method, the Flasher method affords approximately 5000 times more sample per analysis. IV. VINYL CHLORIDE SAMPLE DIE-OUT ON STORED PMCC TUBES In an effort to determine the degree of sample die-out versus time, we loaded several PMCC's with equal volumes of a freshly mixed 5.3 PPM VCI and zero air in a cylinder at 100 psig. Individual samples were then analyzed after storage for 15 days. A calibration sample was run on each tube immediately following its analysis. Percent recovery of the stored VCI ranged from 85% - 98%. Average percent recovery (14 values) was 91% (Table VI). V. BENDIX PMCC-FLA5HER TECHNIQUE FOR OTHER INDUSTRIAL VAPORS The PMCC-Flasher system has been observed to perform well for the other OSHA specified industrial vapors listed in Table VII, Good peak shape has been observed for ail the compounds listed. Typical chromatograms are shown in Figures 4 and 5. sse C Patton, Ph. D VVC 000010902 8 PMCC M1CRONA1R PUMP DATA TABLE I Low Pump Rate Data Time Sec/1 cc cc/min 10:05 AM 33.5, 33.2, 33.0 1.79, 1.81, 1.82 10:45 34.5, 33.0, 32.0 1.74, 1.82, 1.87 12:15 PM 33.0, 33.5, 33.5 1.82, 1.79, 1.79 1:07 34.5, 35.0, 33.0 1.74, 1.71, 1 .82 2:05 33.6, 33.6, 33.2 1.78, 1.78, 1.81 2:55 35.0, 34.0, 36.0 1.71, 1.76, 1.67 4:30 33.6, 33.0, 34.0 1.78, 1.82, 1.76 5:45 35.5, 36.5, 36.6 1.69, 1.64, 1.64 cc/min 1.81 1.81 1.80 1.76 1.79 1.71 1.79 1.66 cc/hr 108.6 108.6 108.0 105.6 107.4 102,6 107.4 99.6 cc/4-hr 434.4 434.4 432.0 422.4 429.6 410.4 429.6 398.4 WC 000010903 9 STAT ON PMCC MICRONAIR PUMP DATA TABLE II Time STAT on 4.0 hr (Initia 1) Performance (cc/min Data) cc/min A & 10:05 AM 1.79, 1.81, 1.82 .00, .02, .03 .0000, .0004, .0009 10:45 1.74, 1.82, 1.87 .05, .03, .08 .0025, .0009, .0064 12:15 PM 1.82, 1.79, 1.79 .03, .00, .00 .0009, .0000, .0000 1:07 1.74, 1.71, 1.82 .05, .08, .03 .0025, .0064, .0009 2:05 1.78, 1.78, 1.81 .01, .01, .02 .0001, .0001, .0004 h= 15 *1=26.89 * = 15 i 4= 0.44 h = 15 1^ = 0.0224 AVE = h/n = 26.89/15 = 1.79 = Average a.d. =0.44 = 0..029= Ave. Deviation * T5" A.D. - a.d. - 0.029 = 0.007 = Ave. Dev. from the mean f*r 7/tr (T = yi'f =1070224= 0.04 = Std. Dev. 2 & = 2 (.04) - 0.08 - 95% Confidence Level % VARawc - (100) - 0.44 0 00) * 1.64% = % AVE. Variance .TTT 237E9 VVC 000010904- STATISTICS ON PMCC MICRONAIR PUMP DATA 10 TABLE III STAT on 7 hr-40 min Performance (cc/min data) <1 Time cc/min A 10:05 AM 1.79, 1.81, 1.82 .01, .04, .05 .0004, .0016, .0025 10:45 1.74, 1.82, 1.87 .03, .05, .10 .0009, .0025, .0100 12:15 PM 1.82, 1.79, 1.79 .05, .02, .02 .0025, .0004, .0004 1:07 1.74, 1.71, 1.82 .03, .06, .05 .0009, .0036, .0025 2:05 1.78, 1.78, 1.81 b 0 8 .0001, .0001, .0016 2:55 1.71, 1.76, 1.67 .06, .01, .10 .0036, .0001, .0100 4:20 1.78, 1.82, 1.76 .01, .05, .01 .0001, .0025, .0001 5:45 1.69, 1.64, 1 .64 1 =42.36, * = 24 AVE = 1.77 .08, .13, .13 = 1.22 .0064, ,0169, .0169 '^^2'= 0.0839 a.d. = A = 1.22 = 0.051 = Ave. Deviation ~~1-- 24 A.D. = a.d. -- .051 = 0,010 = Ave, Dev, from the Mean ^ '/^r~ ) CT' =-~^r %VARavf= = .0839 = 0.06 = Std. Dev. > 2/T = 0.12 = 95% Confidence Le , ~ZT~ J .A (100)= 1.22 0 00) = 2.88% 1n 4ZT35 VVC 000010905 Packing Bendix Modified Charcoal PPM VCl TABLE IV PMCC Vinyl Chloride Breakthrough Data Flow Rate cc/min Sample Time Sample Volume, Li ters Breakthrough Time 11 Breakthrough Volume 50 60 4.0 hr + 14.4/ > 4 hr. 10 1000 0.5 hr + 30 / >0.5 hr 100 100 1 .5 hr 9.0 / 1 .5 hr 1000 100 0.55 hr 3.2/ 0.55 hr 10,000 10,000 50* 100* 1000 1000 100 100 2 min 4 min 1 1 8 min 29 min 2.0/ 4.0/ 11.8/ 2.9 / >2.0 min 4 4.0 min 118 min 29 min 100 5.3** 100 5 80 min 33.0 hr 8.0 / 9.9 / 80 min >33 hr *Water saturated VCl samiples (95% Rel. Hum.) **5.3 PPMCertified Prec ision Gas, Inc. Sampl e in zero air >14.4 / >30 / 9.0 sf 3.2 / >2.0/ <4.0/ 11.8./ 2.9 8.0 >9.9/ TABLE V Extreme Ambient Sampling Con ditions Sample .. 41.8 PPM VCl (Standardized Sample) PMCC Packing ....... Temperature..................... 90F (32C) Rel. Humidity ................. 95% R.H. Flow Rate cc/min 5 cc/min 10 cc/min 25 cc/min Sample Time 55 hr 15.5 hr 6.5 hr Sample Volume liters 16.5 / 9.3/ 9.7/ Breakthrough Time y55 hr 15.5 hr 6.5 hr Breakthrough Volume > 16.5/ 9.3/ 9.7/ wVC 000010906 12 TABLE VI VINYL CHLORIDE RECOVERY FROM STORED PMCC'S Sample .......................... ..................................................................... 300 cc of 5.3 PPM Vinyl Chloride Date Sampled .................................................................................. 11-26-74 Date Analyzed ........................................................................... .. 12-13-74 PMCC PMCC #1 PMCC *2 PMCC *3 PMCC U PMCC #5 PMCC #6 PMCC #7 PERCENT RECOVERY OF VINYL ____________ CHLORIDE 85.6% 87.0 95.0 95.5 98.0 94.0 92.0 Average Percent Recovery .................................................. 91.0% VVC 000010907 TABLE VII OSHA Specified Vapors 1 . Benzene 2. Carbon tetrachloride 3. Chloroform 4. Dioxane 5. Ethylene dichloride 6. Methyl chloroform 7. Methyl ethyl Ketone 8. Styrene 9. Tetrachloroethylene 10. Toluene 11. Trichloroethylene 12. 1,1,2-Trichloroethane 13. Xylene 13 VVC 000010900 FIGURE 3 LINEARITY CURVE 14 WC 000010909 PERSONNEL MONITORING COLLECTION IMN (PMCCI: .cYTICAL COLUMN: 8 FT X 1/8 INCH SS PPN 60/100 FID DETECTOR N2 CARRIER ELECTROMETER 2 X Ifr9 all LEGEND: 1. PMCC INSERT {FLASHER 200C) TEMP PROGRAM ANALYTICAL COLUMN 40-160C e 10/MIN 2.1,2-DICHLOROETHANE (CLCH^H^CL) 3. CHLOROFORM {CHCL3) 4. 1 1 2 TRICHLOROETHANE (^-CH-CH^L) 5. 1,1,2,2-TETRACHLOROETHANE {CL2CHCHCL2) 6. BENZENE (CgHe) FIGURE 4 SLUT CLQilO105 l.Q 16 VVC 000010911