Document Gk6YpjanJZyMQvqapbo1zwnq

DOW CHEMICAL CANADA INC. FORT SASKATCHEWAN, ALBERTA T8L 2F4 NOT /^PROVED FOR OUTSIDE DISTE13UTION INDUSTRIAL HYGIENE MONITORING METHOD January, 1982 CX.-IHM-82-3 Tha Determination of MaChyl Chloride in Air (Gas Chromatographic Method) 1* Scope: 1.1 Analyte: methyl chloride 1.2 Matrix: air 1.3 DIHG: 8 hour time-weighted average (TWA) methyl chloride 50 ppm v/v 1.4 Procedure: adeorptlon onto charcoal at 30 bL/minute flow f r 3 hours, thermal desorption end analysis by gas chromatography with flame ionization detection (GC/FID). 1.5 Range: 3 hour TWA 10 - 500 ppm v/v 1.6 Recovery and Precision (at 95Z confidence level): 95.6Z + 20Z 1*7 Humidity Effect: not determined 1.8 Validation Date: 81/09/14 - 81/11/19 2. Chemical Safety Precautions: Methyl chloride is a colourless, tasteless gas. Its faint etheral odour and mild narcotic effect ere seldom sufficient to provide warning of overexposure. Exposure to methyl chloride causes central nervous system depression which leads to incoordination and drunkennesss. There is no appreciable hazard from akin irritation or absorption from the gas. Methyl chloride should be handled in the fumehood. 3. Principle: 3.1 A measured volume of air is drawn through two stainless steel tubes in series containing Pittsburgh Coconut Base charcoal. Page 1 of 6 DOW CONFIDENTIAL INFORMATION DO 097751 CONFIDENTIAL. January, 1982 Pag* 3 of 6 CJC-IHM-82-3 . 6.2 Thermally desorb Che front and back seedons of both cubes. Analyse by GC/FID using operating conditions as In section 6.3. 6.3 Analyse a PTD blank and a charcosl/PTD blank with aach set of samples. 6.4 Prepare three volume/volume standards using the Bl-M Gas Blander over the range of 10. - 1000 ppm. Analyse the stand ards by GC and plot a calibration curve or calculate the re sponse factor at each level. 6.5 Operating Conditions PTD: desorption temperature desorption time desorption gas 130C 2 minutes ambient air GC: Column - 5 foot 2 1/8 Inch stainless steel packed with 80/100 mesh Porapak P. column temperature Injector temperature detector temperature nitrogen flow hydrogen flow air flow Injection volume attenuation chart speed analysis time 100C 200C 250C 15 at/mlnute 30 mL/mlnute 240 mL/minute lmL 32 0.5 5 minutes A typical chromatogram Is shown In Figure 1* 7. Calculations: 7.1 Calculate the concentration of methyl chloride by comparing areas with external standards. BxC A - -------------- D where A - concentration of methyl chloride In sample (nl/mL) B - concentration of methyl chloride In standard (nL/mL) C - area of methyl chloride in sample (Integrator counts) D area of methyl chloride In standard (lntagrat r counts) DOW 00HFIDEMTIAL DIPOXMATION DO 097752 CONFIDENT!AL January, 1982 Page 5 of 6 OC-IHM-82-3 8*2 The analytical limit of detectl n for methyl chloride la 3 nL/mL which corresponds to a TWA concentration of 0.2 ppm v/v for a 6 litre sample. 8.3 Under the collection conditions described In section 6.1 breakthrough did not exceed 10% in Che second tube at tan times the TLV concentration. 9. Storage Stability Storage studies indicated samples could be stored at -3C f r 3 days without loss of recovery. 10. Sample Tube Packing Sample tubes were peeked with PCB charcoal In the laboratory. The collector tube described Is the only one available for the PTD and has a 0.5g capacity (0.4g front/0.lg back). Tubes were packed on a volume basis.- Studies indicated tubes could be reused after desorption or be repacked. 11. References Kerr, R.W., "The Validation of a Gas Chromatographic Method: Determination of Methyl Chloride In Air", Report Mo. CK-82-45, January, 1982, Western Canada Division. R.W. Kerr Environmental Control/Industrial Hygiene Western Canada Division 'DOW OUHf1DEVT1AL UfFORMATlOH DO 097753 CONFIDENTIAL