FORMALDEHYDE by GC 2541

1 FORMALDEHYDE by GC 2541H2C=0 MW: CAS: 50-00-0 RTECS: LP8925000 METHOD: 2541, Issue 2 EVALUATION: PARTIALI ssue 1: 15 May 1989 Issue 2: 15 August 1994 OSHA ppm; 2 ppm ppm; C ppm; carcinogenACGIH:C ppm; suspected human carcinogen(1 ppm = mg/m3 @ NTP)PROPERTIES:gas; vapor density (air = 1); BP C; explosive range 7 to 73% v/v in airSYNONYMS: methanal; formalin (aqueous 30 to 60% w/v HCHO); methylene oxideSAMPLINGSAMPLER: SOLID SORBENT TUBE (10% (2-hydroxymethyl)piperdine on XAD-2, 120 mg/60 mgFLOW RATE: to L/minVOL-MIN: 1 @ 3 ppm -MAX: 36 LSHIPMENT:routineSAMPLE STABILITY:3 weeks @ 25 C [1]FIELD BLANKS:2 to 10 field blanks per setMEDIA BLANKS: 10 per sample setMEASUREMENTTECHNIQUE:GAS CHROMATOGRAPHY, FIDANALYTE:oxazolidine derivative of formaldehydeDESORPTION: 1 mL toluene; 60 min ultrasonicINJECTION VOLUME:1 L splitless; split vent time 30 secTEMPERATURE-INJECTOR: 250 C -DETECTOR: 300 C -COLUMN: 70 C for 1 min;15 C/min.)

2 Hold @ 240 Cfor 10 minCARRIER GAS:He, 1 to 2 mL/min: makeup flow 29mL/minCOLUMN:capillary, 30 m x ID, m film,DB-Wax or equivalentCALIBRATION:formalin solution spiked on sorbentRANGE:3 to 200 g per sample [2,3]ESTIMATED LOD:1 g per sample [2]PRECISION (S r) @ 38 to 194 g per sample [2]ACCURACYRANGE STUDIED:not determinedBIAS:not determinedOVERALL PRECISION (S rT):not determinedACCURACY:not determinedAPPLICABILITY: The working range is to 16 ppm ( to 20 mg/m3) for a 10-L air sample. The method is suitable for thesimultaneous determinations of acrolein and FORMALDEHYDE . INTERFERENCES: None have been observed. Acid mists may inactivate the sorbent leading to inefficient collection offormaldehyde.

3 A 15 m x ID DB-1301 fused silica capillary column can also be used. This column will also separate theacetaldehyde and acrolein oxazolidines. A nitrogen-specific detector (NPD) can be used for improved METHODS: OSHA Method 52 is similar but uses slightly larger sampling tubes [2]. This method has improved samplestability and ease of personal sampling compared to NIOSH Methods 2502 (which has been withdrawn), 3500 and , Method 3500 (chromotropic acid) is the most sensitive. NIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 FORMALDEHYDE : METHOD 2541, Issue 2, dated 15 August 1994 - Page 2 of 5 REAGENTS: , chromatographic quality.

4 (Hydroxymethyl)piperidine (2-HMP).Recrystallize several times from isooctaneuntil there is one major peak (>95% of area)by GC analysis. Store in desiccator. solution, 37%*. * stock solution, 1 mg/mL (seeAppendix A). acid, N. hydroxide, N. sulfite (Na2SO3), M. Preparefresh immediately before use. , deionized, distilled , , , sulfate.*See SPECIAL PRECAUTIONSEQUIPMENT: : glass tube, 10 cm long, 6-mmOD, 4-mm ID, with flame -sealed ends andplastic caps, containing two sections of2-(hydroxymethyl) piperidine-coated XAD-2 (see APPENDIX B) (front = 120 mg;back = 60 mg) retained and separated bysmall plugs of silanized glass drop across the tube at airflow must be less than 760 kPa( mm Hg).

5 Tubes are commerciallyavailable (Supelco ORBO-23; SKC 226-118; or equivalent). sampling pump, to L/min,with flexible connecting tubing. chromatograph, flame ionization detector,integrator and column (page 2541-1). water bath. , glass, 2-mL, with PTFE-lined crimpcaps. , volumetric, 10-, 25-, and 50-mL. , volumetric, 1-, 2-, and 10-mL with pipetbulb. , 10-mL (readable to mL), 25-,and 50-mL. , , , round-bottomed, extraction PRECAUTIONS: FORMALDEHYDE isviewed as a potential occupational carcinogen[4,5]. each personal sampling pumpwith a representative sampler in ends of the sampler immediately before sampling.

6 Attach sampler to personal samplingpump with flexible at an accurately known flow rate between and L/min for a total sample size of1 to 36 : FORMALDEHYDE reacts with 2-(hydroxymethyl)piperidine on the sorbent bed duringsampling. Sampling rate is limited by the speed of this reaction. Sampling above may cause appreciable breakthrough owing to incomplete reaction, possiblyinvalidating the sample. Further discussion of this reaction is included in Ref. [6]. the samplers and pack securely for each sampler with a file in front of the first sorbent sampler at score line. Remove and place front glass wool plug and front sorbent sectionNIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 FORMALDEHYDE : METHOD 2541, Issue 2, dated 15 August 1994 - Page 3 of 5in a back section with remaining glass wool plugs to a second mL toluene to each vial.

7 Crimp cap tightly onto each :An appropriate internal standard, such as 1 L/mL dimethylformamide, may be added atthis point [3]. vials in an ultrasonic water bath for 60 AND QUALITY daily with at least six working standards, in duplicate, covering the range of ten 120-mg portions of the coated sorbent into 4-mL vials with septum caps. If the bulk coated sorbent is not available, remove the front section from ten unusedsamplers (media blanks). aliquots of FORMALDEHYDE stock solution into the vials at six different levels and allow tosit overnight at room temperature. Use serial dilutions of the calibration stock solutions tospike the absorbent in the range of Desorb (steps 7 through 9) and analyze (steps 12 and 13) with samples and Prepare calibration graph (peak area or peak height) vs.

8 G of three quality control blind spikes and three analyst spikes to ensure that thecalibration graph is in gas chromatograph to manufacturer's recommendations and to conditions given onpage 2541-1. Inject 1- L sample :If the amount of oxazolidine in the aliquot exceeds the capacity of the column,dilute the sample with toluene, reanalyze, and apply the appropriate correctionfactor in peak area or peak height. For FORMALDEHYDE derivative tr = min and for 2-(hydroxymethyl)piperidine tr = min under these :If necessary, verify the identity of the FORMALDEHYDE oxazolidine by comparisonof retention time with an authentic sample (see APPENDIX C).

9 The mass, g (corrected for DE) of oxazolidine derivative found in the sample front(Wf) and back (Wb) sorbent sections from the calibration : if Wb > Wf/10, report breakthrough and possible sample concentration, C (mg/m3), of FORMALDEHYDE in the air volume sampled, V (L):NOTE:Because the working standards are prepared on media blanks, no additional blank correction isnecessary. Report field blanks as OF METHOD:This method is similar to OSHA Method 52 [2]; however, the OSHA samplers contained 20% morecoated sorbent than the samplers used in this method. In a study by OSHA, 5% breakthrough occurredafter 396 min at a flow rate of L/min and a test atmosphere concentration of mg/m3.

10 The relativeNIOSH Manual of Analytical Methods (NMAM), Fourth Edition, 8/15/94 FORMALDEHYDE : METHOD 2541, Issue 2, dated 15 August 1994 - Page 4 of 5humidity in the study was 49% at 24 C. A storage study was done by NIOSH/MRSB [1] by spikingsamplers at two concentrations, and g/sample [1]. Three spikes at each concentration werestored at different temperatures for seven days. The storage conditions were as follows:Sample set time120 C7 days2 (a)20 and 40 C1 day (b)20 C6 days34 C (refrigeration)7 daysThe recovery of FORMALDEHYDE was essentially 100% for all of the storage :[1]Williams, K. J. Methods Development Efforts, NIOSH/MRSB, (NIOSH, Unpublished,1989).