Isopropyl Ether (1618)
ISOPROPYL ETHER ((CH3)2CH)2 O
MW: 102.18
METHOD: 1618, Issue 2
1618
CAS: 108-20-3
RTECS: TZ425000
EVALUATION: PARTIAL
OSHA : 500 ppm NIOSH: 500 ppm ACGIH: 250 ppm; STEL 310 ppm
Issue 1: 15 August 1994 Issue 2: 15 March 2003
PROPERTIES: liquid; 0.725 g/mL @ 20°C; BP 67.5°C; VP 15.9 kPa (119 mm Hg, 15.7% v/v) @ 20°C; explosive range 1.4 to 7.9% v/v in air
(1 ppm = 4.18 mg/m3 @ NTP) Synonyms: diisopropyl ether; 2-isopropoxypropane; 2,2'-oxybispropane
SAMPLING SAMPLER:
Solid Sorbent Tube (coconut shell charcoal; 100 mg/50 mg)
FLOW RATE:
0.01 to 0.05 L/min
VOL-MIN: -MAX:
0.1 L @ 500 ppm 3L
SHIPMENT:
Routine
SAMPLE STABILITY:
30 days @ 5 °C
BLANKS:
2 to 10 field blanks per set
ACCURACY RANGE STUDIED:
992 to 4260 mg/m3 [2] (3-L samples)
BIAS:
2.2%
MEASUREMENT TECHNIQUE:
GAS CHROMATOGRAPHY, FID
ANALYTE:
Isopropyl ether
DESORPTION:
1 mL CS2 ; stand 30 min
INJECTION VOLUME:
1 µL
TEMPERATURES -INJECTION: 250 °C -DETECTOR: 300 °C -COLUMN: 35 °C (1 min) - 150 °C ramp (10 °C /min) CARRIER GAS:
Helium (1-2 mL/min)
COLUMN:
Capillary, fused silica, 30-m x 0.32-mm ID; 3:m film 100% dimethyl siloxane
CALIBRATION:
Solutions of analyte in CS 2
RANGE:
2 to 651 µg per sample (capillary column); 1000 to 12000 µg per sample (packed column)
OVERALL PRECISION (Ö r T ): 0.056 ACCURACY:
±12.0%
ESTIMATED LOD: 0.2 µg per sample [1] PRECISION ( þ r ):
0.014 [1]
APPLICABILITY: The working range is 3 to 1170 ppm (16 to 4900 mg/m3 ) for a 3-L air sample [1]. The sorbent's capacity for the analyte has not been determined under conditions of high relative humidity [2].
INTERFERENCES: Any compound that has a similar retention time under these analytical conditions.
OTHER METHODS: This method is based on and supercedes S368 [3] and NMAM 1618 (Issue 1) [5].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ISOP RO PYL ET HER : MET HO D 161 8, Issue 2, dated 15 M arch 200 3 - Page 2 o f 4 REAGENTS:
EQUIPMENT:
1. Eluent: Carbon disulfide* (CS2), chrom ato graphic quality. 2. Isopropyl ether*, reagent grade. 3. Helium, prepurified and filtered. 4. Hydrogen, prepurified and filtered. 5. Air, prepurified and filtered.
1. Sampler: glass tube, 7 cm long, 6-mm OD, 4-mm ID, flame-sealed ends, containing two sections of activated coconut shell charcoal (front = 100 m g, back = 50 m g) separated by a 2-mm urethane foam plug. A silanized glass wool plug precedes the front section, and a 3-mm urethane foam plug follows the back section. Tubes are comm ercially available. 2. Personal sampling pumps (0.01 to 0.05 L/min) with flexible tubing. 3. Gas chromatograph, FID, integrator, and Rtx®1 or equivalent capillary column (see page 16 18-1). 4. Glass a utos am pler vials (2-m L) with PTFE-lined caps. 5. Pipettes (1-mL) and pipette bulb. 6. Microliter syringes, 10-µL and convenient sizes for making dilutions . 7. Volum etric flasks (10-m L).
- See SPECIAL PRECAUTIONS
SPE CIAL PRECAUTIONS: Carbon disulfide is toxic and highly flamm able (flash point = -30 °C); isopropyl ether is flam m able and tends to fo rm exp losive pero xides [4]. Prepare samples and standards in a well-ventilated hood. SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Break the ends of the sam pler im m ediately befo re sa m pling. Attach the sam pler to a personal sampling pump with flexible tubing. 3. Sa m ple at an accurately known flow rate betw een 0.01 and 0.05 L/m in for a total sam ple size of 0.1 to 3 L. 4. Ca p the sam plers and pac k secu rely for shipm ent.
SAMPLE PREPARATION: 5. Place the front and back sorbent sections of the sampler tube in sep arate vials. Include the glass wool plug in the vial with the front sorbent section. Discard the foam plugs. 6. Ad d 1.0 m L eluent to each vial. Attach crim p cap to each vial im m ediate ly. 7. Allow to stand at least 30 min with occasional agitation.
CALIBRATION AND QUALITY CONTRO L: 8. Ca librate daily with at leas t six wo rking standa rds from below the LOD to 10 times the LO Q. Additional sta ndards m ay be added to exte nd the calibra tion curve if ne cessary. a. Add known amounts of isopropyl ether to eluent in 10-mL volumetric flasks and dilute to the mark. Prepare additional standards by serial dilution in 10-mL volumetric flasks. b. Analyze with samp les and blanks (steps 11 and 12). c. Prepare a calibration graph (pe ak area of analyte vs. mg of ana lyte per sam ple). 9. Determine the desorption efficiency (DE) at least once for each lot of charcoal used for sampling in the calibra tion ran ge (s tep 8).
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ISOP RO PYL ET HER : MET HO D 161 8, Issue 2, dated 15 M arch 200 3 - Page 3 o f 4 a. Prepare three tubes at each of five levels plus three media blanks. b. Rem ove and disca rd the back sorbent sec tion of a blank sam pler. c. Inject a known amount of stock solution (1 to 20 µL) directly onto the front sorbent se ction with a microliter syringe. d. Allow the tubes to air equilibrate for several minutes, then cap the tubes and allow to stand overnight. e. Deso rb (steps 5 through 7 ) and analyze with standards and blank s (steps 11a nd 12). f. Prepare a graph of DE vs. µg analyte recovered. g. Analyze a m inim um of thre e qu ality contro l blind sp ikes and three a nalyst spikes to insure that the calibra tion gra ph and D E graph are in control. h. Analyze at least three quality control blind spikes and three analyst spikes to insure that the calibration grap h an d DE graph are in c ontro l.
MEASUREMENT: 10. Set the gas chromatograph according to the manufacturer's recomm endations and to the conditions given on page 1618-1. Inject a 1-µL aliquot manually using a solvent flushing technique or with an auto sam pler. NOTE: If the peak a rea is above the linea r range of the w ork ing sta nda rds, dilute with so lvent, reana lyze and apply the appropriate dilution factor in the calculations. 11. Measure the peak area.
CALCULATIONS: 12. Determine the mass, µg (corrected for D E), o f analyte found in the sam ple front (W f) and back (W b) sorbent sec tions, and in the average m edia blank front (B f) and back (B b) sorbent sections. NOTE: If W b > W f / 10, report breakthrough and possible sample loss. 13. Calculate the concentration, C, of analyte in the air volume, V(L), sampled:
EVALUATION OF METHOD: Issue 1 S368 was issued on April 21, 1976 [3] and validate d over the rang e 99 2 to 4260 m g/m 3 for 3-L air samples from dynamically generated test atmospheres [2]. The isopropyl ether concentrations were verified by G C/F ID analysis. Breakthrough (5% on the backup section) occurred at 26 min when sam pling a test atmo sphere con taining 426 0 m g/m 3 of isoprop yl ether in dry air at a flow rate of 0.19 8 L/m in. Issue 2 The desorption efficiency, at levels ranging from 10 times the LOQ to 0.1 times the REL, was determined by spiking kn ow n am ounts of is opropyl ether (in CS 2) on coconut shell charcoal tubes. The isopropyl ether exhibited acc epta ble de sorption e fficiency recovery resu lts (97.1% - 103 .4%) o ver the 20 to 651 :g range evaluated [1]. Isopropyl ether was evaluated for its storage stability. Sorbent tubes were spiked at approxim ate ly 615 µg and stored at ambient temperature for 7 days, then transferred to a refrigerator at 5° C. Sam ples were analyzed after 7, 14, and 30 days. Average recovery was 101.1%, 98.7%, and 94.8% respectively [1]. For this issue, the analytical range is lowered due to increased sensitivity and resolution with cap illary colum n ch rom atog raph y. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition ISOP RO PYL ET HER : MET HO D 161 8, Issue 2, dated 15 M arch 200 3 - Page 4 o f 4 REFERENCES: [1] [2]
[3]
[4]
[5]
Pendergrass SM, Ma y LR [2002 ]. NM AM 161 8 Ba ckup D ata Report, C incinn ati, OH : National Ins titute for O ccu pation al Safety & H ealth, D AR T, F ebru ary. NIOSH [1 9 77 ]. D oc u me n ta tion of the NIOSH Validation Tests, S368. U.S. Department of Health, Education, and Welfare, Publ. (NIOSH) 77-185. Av ailable as GPO Stock #017-033-00231-2 from Superintendent of Documents, Washington, DC 20402. NIOSH [19 77 ]. N IO SH M an ua l of Analyti cal Methods, 2nd ed., Vol. 3, S368, U.S. Department of Health, Education, and We lfare, Publ. (NIOSH ) 77-157-C. Method S 368 w as originally validated under NIOSH C ontract CDC-99-74-45. N IO S H /O S H A [19 81 ]. N IO SH /O SH A O cc up ation al H ealth Guidelines for Chemical Hazards, U.S. Department of Health and Human Services and U.S. D epa rtme nt of Lab or, Publ. (NIOSH) 81-123, January. Ava ilab le as GPO Stock #17-033-00337-8 from Superintendent of Documents, Washington, D.C. 20402. NIOSH [1994]. NIOSH Manual of A nalytical Method s, 4 th ed., supp lem ent, N MA M 1 618 , Depart. of He alth and Hum an S ervices, D HH S (N IOS H) P ublica tion N o. 94-113 .
METHOD UPDATED BY: Step hanie M. Pen derg rass, NIOS H/D AR T. Leroy R. May, NIOSH/ PRL. Method originally written by Charles V. Cooper, NIOSH/DPSE.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition