2-(Dimethylamino)ethanol and 1-Dimethylamino-2-propanol (2561)
(1) 2-(DIMETHYLAMINO)ETHANOL (2) 1-DIMETHYLAMINO-2-PROPANOL
FORMULAS: TABLE 1
MW: TABLE 1
METHOD: 2561, Issue 1
CAS: TABLE 1
EVALUATION: PARTIAL
RTECS: TABLE 1 Issue 1: 15 March 2003
PROPERTIES: Table 1
OSHA: no REL NIOSH: no PEL ACGIH: no TLV COMPOUNDS:
2561
(1) 2-(dimethylamino)ethanol: dimethylethanol amine (2) 1-dimethylamino-2-propanol: dimethylisopropanolamine SAMPLING
SAMPLER:
SOLID SORBENT TUBE (XAD-7, 60 mg/30 mg)
FLOW RATE:
0.02 to 0.1 L/min
VOL – MIN: – MAX:
10 L 24 L
SHIPMENT:
Cold
SAMPLE STABILITY:
Stable stored in freezer
BLANKS:
2 to 10 field blanks per set
MEASUREMENT TECHNIQUE:
GAS CHROMATOGRAPHY, FID
ANALYTE:
Compounds above
DESORPTION:
1 mL methanol, 60 min
INJECTION VOLUME:
1 µL
TEMPERATURE -INJECTION: 250 °C -DETECTOR: 300 °C -COLUMN: 70 °C for 6 min then up to 200 °C for 4 minutes at a rate of 15 °C per minute CARRIER GAS: Helium, 1-2 mL/min
ACCURACY RANGE STUDIED:
Not studied
BIAS:
Not determined
COLUMN:
Capillary, fused silica, 30-m x 0.25-mm ID; 1.0-µm film dimethylpolysiloxane, DB-1 or equivalent
CALIBRATION:
Solutions of compounds in methanol
OVERALL PRECISION (S r t):
Not determined
RANGE:
0.004 to 2 mg per sample [1, 2, 3]
ACCURACY:
Not determined
ESTIMATED LOD:
See Table 2
PRECISION ( þ r ): See Table 2 APPLICABILITY: This method can be used for simultaneous analysis of both amino compounds. The method was field tested for almost 300 samples containing both compounds with little or no breakthrough [2, 3] . Up tp 4 mg of dimethylethanolamine (no isopropanolamine present) and up to 1200 :g dimethylisopropanol (140 :g dimethylethanolamine present) were reported on the field samples with little breakthrough. For higher capacity, a larger XAD-7 sorbent bed tube can be used. NOTE: During method development, a capillary Rtx-5Amine (cross-linked 5% diphenyl/95% dimethyl polysiloxane) column with deactivated injection port liner was also used successfully.
INTERFERENCES: None identified.
OTHER METHODS: This method may be applicable to other amino alcohols such as those in method 2007 [4 ].
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition AM INO E TH ANO L CO MP OU ND S: ME TH OD 2561, Issue 1, dated 1 5 Ma rch 2003 - Page 2 of 4 REAGENTS:
EQUIPMENT:
1. 2. 3. 4. 5.
1.
Eluent: m etha nol* (chrom atog raph ic grade). Ana lytes, 99+% grade *. Helium, purified. Hydrogen, prepurified. Air, compressed, filtered.
- See SPECIAL PRECAUTIONS.
2. 3. 4. 5. 6. 7. 8.
Sampler: glass tube, 7-cm long, 6-mm OD, flame-sealed ends, containing two sections of XAD-7 resin (front = 60 mg; back = 30 mg) separated by glass wool. Pressure drop across the tube at 0.1 L/min. airflow must be less th an 3.2 kP a. T ubes are com m ercially available (SKC, Inc. #226-94). Personal sampling pump, 0.01 to 0.2 L/min, with flexible connecting tubing. Refrigerant, bagged (“Blue Ice” or equivalent). Gas chromatograph, FID, integrator and colum n (page 25 61-1). Vials, glass, 2-mL, PTFE -lined crimp caps. Syringes, 10-µL to 500-µL. Volumetric flasks, 10-mL. Pipet, volumetric, 1-mL, with pipet bulb or repipet.
SPECIAL PRECAUTIONS: Methanol is toxic and flamm able. The analytes are eye irritants [2]. W ear appropriate protective clothing and work with these compounds in a well ventilated hood.
SAMPLING: 1. Calibrate each personal sampling pump with a representative sampler in line. 2. Break the ends of the sampler imm ediately before sampling. Attach sampler to personal sam pling pum p with flexible tubing. 3. Sa m ple at an acc urate ly known flow ra te betw een 0.02 and 0.1 L/m in for a total sam ple size of 10 to 24 L. 4. Cap the s am plers with plastic (not ru bbe r) caps a nd p ack sec urely for shipm ent w ith bag ged refrige rant.
SAMPLE PREPARATION: 5. Place the front and back sorbent sections of the sampler tube in separate vials. The initial glass wool plug may be discarded. 6. Ad d 1.0 m L of m eth anol eluent to each vial. Attac h crim p cap to each vial. 7. Allow to stand 60 min with occasional agitation.
CALIBRATION AND QUALITY CONTRO L: 8. Calibrate with at least six working standards over the range 4 to 4000 :g analyte per sample. a. Add known amounts of analyte to eluent in 10-mL volumetric flasks and dilute to the mark. b. Analyze together with samp les and blanks (steps 11 and 12). c. Prepare calibra tion gra ph (ratio of pea k area o f ana lyte vs. :g analyte). 9. Determine desorption efficiency (DE) at least once for each lot of XAD-7 used for sampling in the calibration range (step 8). Prepare three tubes at each of five concentrations plus three media blanks. a. Rem ove and disca rd back sorbent sec tion of a blank sam pler. b. Inject a known amount of analyte directly onto front sorbent section with a microliter syringe. c. Ca p the tube. Allow to stand overnight. d. Deso rb (steps 5 through 7 ) and analyze together with working standards (steps 11 and 12). e. Prepare a graph of DE vs. mg analyte recovered.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition AM INO E TH ANO L CO MP OU ND S: ME TH OD 2561, Issue 1, dated 1 5 Ma rch 2003 - Page 3 of 4 10. Analyze three quality control blind spikes and three analyst spikes to ensure that the calibration graph and D E graph are in control.
MEASUREMENT: 11. Set gas chromatograph according to manufacturer’s recomm endations and to conditions given on page 2561-1. Inject sample aliquot with autosampler, or manually using solvent flush technique. NOTE: If peak area is above the linear range of the working standards, dilute with eluent, reanalyze, and apply the appropriate dilution factor in calculations. 12. Mea sure peak area. Divide the peak area of an alyte by the peak area of internal standard on the sam e chromatogram.
CALCULATIONS: 13. Dete rm ine the m ass , :g (corrected for D E), of 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) sorben t. NOTE: If W b > W f/10, report breakthrough and possible sample loss. 14. Calculate conce ntration, C, of analyte in the air volume sam pled, V (L):
EVALUATION OF METHOD: Current Validation This method was developed in response to a request for a method to use in a field study. The m ethod for dimethylethanolamine and dim ethylisopropanolamine was validated using analytes fortified on XAD-7 sorbent tubes (SKC, Inc. #226-94, Lot 1994). Desorption efficiency (DE) and precision are listed in Table 2. Storage stability studies were done at approximately 100 µg each analyte/sample. The sam ples were stored for up to 5 weeks in the freezer (-4°C). The recovery for dimethylethanolamine (110.9 :g/sample) was 98.4% and for dimethylisopropanolamine (104.6 :g/sample) w as 100.2% .
REFERENCES: [1] Grote AA[2002]. NIOSH Backup Data Report for NIOSH m ethod 2561. Nationa l Institute for Occupational Safety and He alth, DART /CEM B, Cincinnati, OH. (unpublished repo rt). [2] NIOSH [2002]. Evaluation of Visual Disturbances Related to Amine Exposure. Cincinnati, OH: U.S. Department of Health and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 200101444-2867. [3] DataChem Laboratories [2001]. NIOSH Analytical Reports for NIOSH Sequence 9675-CA through -CH. Cincinnati, OH: National Institute for Occupational Safety and Health, DAR T/CE MB . (unpublished, May). [4] NIOSH [1994]. Aminoethanol Compounds l: Method 2007. In: Eller PM, Cassinelli ME, eds. NIOSH Manual of Analytical Methods, 4 nd ed. C incinn ati, OH : U.S. Departm ent of He alth and Human Services, Pu blic Health Service, Centers for Disease Control and Prevention, National Istitute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 94-113.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition AM INO E TH ANO L CO MP OU ND S: ME TH OD 2561, Issue 1, dated 1 5 Ma rch 2003 - Page 4 of 4 METHOD WRITTEN BY: Ardith A. Grote, NIOSH/DART
TABLE 1. Structural Formulas, Molecular Weights, and Properties Compound
CAS
RTECS
Formula
2-(dimethylamino)ethanol
108-01-0
KK6125000 HOCH2 CH2 N(CH3 )2
1-dimethylamino-2-propanol
108-16-7 UB3150000 (CH3 )2 NCH2 CH(OH)CH3
MW
mg/m3 = 1 ppm
BP (ºC)
89.14
0.274
133
6.12
0.887
103.17
0.237
124
8.0
0.837
VP Density (mm Hg) (g/mL)
TAB LE 2. Current Validation
Compound
Range Studied
LOD
(µg / sample)
(µg / sample)
Average DE1
Measurement Precision ( Ö r)
2-(dimethylamino)ethanol
22-554
4
0.930
0.026
1-dimethylamino-2-propanol
21-523
4
0.894
0.029
1
Averaged over mass range shown.
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition