9 1 K o r e a n In d. H y g. A s s oc. J V o l. 9, N o. 1. M a y, 1 9 9 9 - A bs tract- T he Dev elopment of New Diffus ive Sampler for F ormaldehyde in Air. Mee- heon Choe, Kw ang- Mook Lee, and Young- Man Roh Departm ent of Occupational H ygiene, Graduate School of Occupational H ealth, T he Catholic U niversity of K orea, Seoul, K orea T o utilize diffuse sampling of formaldehyde in air, a new sampler was designed. A glass fiber filter was impegnated with 2,4- dinitrophenylhydrazine(dnp) and phosphoric acid and mounted 37 cassette. T he formaldehyde vapor was sampled in the dynamic chamber and measured by high performance liquid chromatograph and compared with solid sorbent tube. T he results were as follows ; 1. T he desorption efficiencies of diffusive sampler between 97.0% and 100%. 2. The sampling rate is constant as in 58 61.8 /min when sampling times are between 120 and 360 min. 3. T here was a significant relationship between concentrations of diffusive samples and active samples with the coefficient of determination(r2) of 0.92. - 173 -
4. Desorbed amount of formaldehyde diffusive sampler was increased by high relative humidity. 5. Wheth diffusive samplers were stored at room temperature or at refrigerator there was no statistically significant difference in the accuracy of result. 6. When the diffusive samplers, which collected formaldehyde vapor, were exposed to clean air for three hours, there was no significant loss of formaldehyde due to reverse diffusion. In conclusion, this study suggest that developed diffusive samplers will be a reasonable substitute for the solid sorbent tube for sampling formaldehyde and practical comparitive study of developed diffusive sampler should be performed at workplaces of manufacturing industry..,,,,,,,,,,,,,,.,,,,,,,, ( ),,. (, 1996)... (, 1996). (International Agency for Research on Cancer : IARC) (, 1995). bis- chloromethyl ether(bmce) (Frankel et al, 1979). (National Institute for Occupational Safety and Health, NIOSH) (potential occupational carcinogen). 37% 50% (, 1995). NIOSH 3500 ( ), 2541 (, NIOSH No. 2541). (Levin et al, 1985 ;, 1993), (NIOSH, 1994 ;, 1995). - 174 -
,, (Feigley, 1982).,. (Feigley, 1982).., NIOSH 2541..... Fick 1 (Lautenberger et al, 1980 : Rose & Perkins, 1982 : Palmes et al, 1986 ). W = - DA dc dx...(1) W = (mass transfer rate, ng/sec) D = (diffusion coefficient, /sec) A = (cross sectional area of diffusion path, ) dc/dx = {the instantaneous rate of change in concentration over diffusion path, (ng/ )/ } (1) (L) ( C 1 -. C 0 ) (2) W = D A L ( C 1- C 0 )...(2) L C 1 C 0 =, =, ng/ =, ng/ C 0 0 (2) C 0 = 0 (t) (3). M = D A L ( C 1) t...(3) M =, ng t =, sec (3) DA/L /sec. (sampling rate, SR). - 175 -
. (3) (4). C 1 = ML DA t...(4). L A, M, t. D
(dynamic system) (Permeater PD- 1B, Gastec, Japan) (Yao & Krueger, 1993 ;, 1993)., 35. 20 20 30.
., (Alnor System, Model 360). (Gilian, M- odel LFS113D, USA) 0.1 /min. (Junsei chemical Co, Japan) 24 (Junsei c- hemical Co, Japan) (Aldrich chemical, USA) 1 60 GC. (formaldehyde oxazolidine, SUPELCO, U- SA). GC Table 1. acetonitrile(em Science, USA) 3 1. 0.45 pore size Millex- SR Filter 10 HPLC. formaldehyde- 2,4- DN- PH(SUPELCO, USA). HPLC T able 2. Table 1. Analysis condition of gas chromatography Variance System Gas chromatograph Detector Column Operating conditions Carrier gas Flow rate Injection volume Injection temperature Detection temperature Oven temperature Condition HP Flame Ionization Detector(FID) HP- FFAP 25m 0.32 0.52 He 30 /min 2 200 250 80, isothermal Table 2. Varia nce HPLC Column Pum p Mobile phase Flow rate Detecter Analysis condition of High Performance Liquid Chromatograph conditions Injection volum e 3. 1) 2 0.5 T LV, 1.0 T LV, 1.5 T LV, 2.0 T LV HPLC. 2) 2 3. Fick. 1.0 15 360. 1.0, 0.5, 0.1 3. Condition W aters Nova- Pak C18 3.9 * 150 M odel 600E DW : Methanol(40 : 60, V /V ) 0.8 / m in is ocratic UV, 365 10-178 -
0.5 20% 80%. 3). 1.0 3 (2 4 25 ) (4 6 ) 1, 3, 7. 4). 1.0 30, 2, 4 3. Table 3. Desorption efficiency of formaldehyde from 2,4- DNP- coated filters(n=6) Amount spiked ( ) 8.75 17.5 26.25 35 2... 1) Value measured Mean( ) SD 8.55 17.50 25.80 34.60 0.12 0.15 0.15 0.36 * Des orption E fficiency ( % ) = 7 V alue meas ured ( ) 100 A mount s piked ( ) Desorption efficiency (%) 97.1 100.0 98.3 98.9 T able 4 1.0 15 6 Fick 68 /min 15 30.4 /min, 2 58 61.8 /min. 4. SAS. t- test,. 25%.. 1. T able 3 6 97.1 100%. F ig. 3. Effect of s am pling tim e on sampling rate of diffusive sampler. - 179 -
Table 4. Effect of formaldehyde concentration on sampling rate of diffusive sampler ( Mean SD) HCHO level Sampling time. min (t) Amount measured by sampler. (Q) / Concentration meas ured by NIOSH method / (C) Calculated SR* / min 1.0 T LV 18 120 240 2.635 0.29 2.148 0.23 9.067 1.30 1.109 0.16 18.228 0.90 1.114 0.06 3.923 0.04** 1.271 0.06 1.229 0.03 30.4 59.5 61.8 0.5 T LV 15 120 240 1.520 0.08 1.487 0.08 5.411 0.69 0.662 0.08 10.795 0.96 0.660 0.06 2.781 0.01** 0.738 0.01 0.748 0.02 36.4 61.1 60.1 0.1 T LV 15 120 240 0.426 0.09 0.417 0.09 1.587 0.04 0.194 0.01 3.245 0.05 0.198 0.00 0.881 0.16 0.219 0.04 0.217 0.02 32.2 60.4 62.3 * SR = Sampling Rate= ** P< 0.01 Q ( C )( t ) 1, 000 2) T able 4 1.0, 0.5, 0.1 15 30.4 36.4 /min 2 4 59.5 62.3 /min 15 1.0, 0.5 (P< 0.01). Fig. 4. Y = 1.84X - 0.30 (R =0.92). (R=0.96). 3) T able 5 0.5 80% 20%. T able 5 20% 15 80%99 15 240 (P< 0.01). 120 240 15, (P< 0.01). 3. T able 6 7 2.5%, 1%, 1 7 (P> 0.05). 8% 24% NIOSH 25%. 4. T able 7 30, 2, 4-180 -
3 (P> 0.05).. 30 240 3 3 9% 28%. Fig. 4. Correlation of concentration of formaldehyde betw een diffus ive and active samples..,,,, (Environmental Protection Agency : EPA) 0.1ppm 0.5ppm 1.0ppm 3.0ppm (Ness, 1991).,.. NIOSH 3 75%. 4 97.1 100%. NIOSH 120 58 61.8 /min. Levin 60.9 /min 3.7 /min(levin et al, 1986),,. Kring 68 /min, Fick 0.16 /sec (Kring et al, 1982). (1996) GC HPLC 3, 2.5 HPLC GC. GC HPLC. SKC (, 1996). 15 30.4 36.4 /min, 2 59.5 62.3 /min 8% 62%. Feigly 27% 61% (Feigly & Lee, 1987). 15 30.4 36.4 /min 2-181 -
T able 5. Effect of relative humidity on sampling rate of diffusive sampler and active sampler RH % S a m p l i n g time min (t) Amount measured by sampler (Q) / Concentration measured by NIOSH method / (C) Calculated SR* /min 20 15 120 240 1.520 0.08 1.487 0.08 5.411 0.69 0.662 0.08 10.795 0.96 0.660 0.06 2.781 0.01 0.738 0.01 0.748 0.02 36.4** 61.1 60.1 80 15 120 240 1.883 0.03 1.842 0.03** 5.927 0.48 0.725 0.06 10.966 0.63 0.670 0.04 3.273 0.03** 0.804 0.00** 0.800 0.03** 38.4** 61.4 57.1** RH : Relative humidity * SR = Sampling Rate= ** P< 0.01 Q ( C )( t ) 1000 T able 6. Effect of storage stability in diffus sampler (n=3) Item (unit) 1 day (A)** 3 days 7 days Room temp Mean( ) 11.855 11.760 11.562* SD 0.83 1.28 1.32 RSD 0.07 0.11 0.11 Bias*** < 0.01 0.02 Accuracy****(%) 22 24 Refrigeration Mean 11.832 11.742* SD 0.52 0.78 RSD 0.04 0.07 Bias < 0.01 0.01 Accuracy 8 15 * P> 0.05 * Data on day 1 w ere used as reference value( A ) *** Bias = ( V alue meas ured on each time) - A A **** A ccuracy(% ) = Bias + 2(RSD) 100 15 (Short term exposure limits : ST EL) 30 (Cassinelli et al, 1987). 0.1 /min 2 59.5 62.3 /min. (1996) n- hexane 2 37 71-182 -
T able 7. Reverse diffusion of formaldehyde in diffusive sampler (N=3) Sampling time (min) Item (unit) A (A) B 30 Mean( ) 2.465 2.465* SD 0.38 0.35 RSD 0.15 0.14 Bias < 0.01 Accuracy(%) 28 120 Mean 12.191 12.258* SD 0.86 0.79 RSD 0.07 0.06 Bias 0.01 Accuracy(%) 13 240 Mean 24.464 24.448* SD 0.98 0.99 RSD 0.04 0.04 Bias 0.01 Accuracy(%) 9 A : Without expos ure, formaldehyde vapors w ere collected for 30 minutes and for tw o and four hours and immediately analyzed. B : With exposure, formaldehyde vapors w ere collected for 30 minutes and for tw o and four hours and the samplers were expos ed to clean air for three hours to evaluate revers e diffusion. * P> 0.05 ** Data on immediately w ere used as reference value( A ) *** Bias = ( V alue measured on each time) - A A **** A ccuracy(% ) = Bias + 2( RSD) 100 /min 2. (R) 0.96 1.84, Levin (1986) 0.96 0.91. 15 1.0, 0.5, 0.11ppm, 0.27ppm, 0.29ppm(, 1996).. (P< 0.01), 2 (P< 0.01). - 183 -
. Smith 0.85ppm 0.52ppm, 1.16ppm 1.02ppm (Smith et al, 1983) 7 2.5%, 1% (P> 0.05). 3M 87 104%. SKC 100 5%, Gilian 88 108% (, 1996).,, (Cassinelli et al, 1987). T able 7 30, 2, 4 3 99.9 100.5%.. 2, 2.,.,... DNP 37.,,,,,,.. 1. 97.1% 100%. 2. 120 360 58 /min 61.8 /min. 3. (R2) 0.92. 4.. 5.. 6. 3., (2 ),, NIOSH. - 184 -
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(NMAM), 4th ed, Method No 2541. Ohio : NIOSH, 1994. Ness S A. Air Monitoring for T oxic Exposures. 1991 : 452 470. Palmes E D, Burton R M, Ravishankar K, Solomon J J. A sampler mathematical model for diffusional sampler operation. Am. Ind. Assoc. J. 1986 ; 47 : 418 420. Rose V E and Perkins J L. Passive dosimetry state of the art review. Am. Ind. Assoc. J. 1982 ; 43 : 605 621. Smith D L, Michele Bolyard, E R Kennedy. Instability of formaldehyde air samples collected on a solid sorbent. Am. Ind. Assoc. J. 1983;44:97 99. T ompkins F C and R L Goldsmith. A new personal dosimeter for monitoring of industrial pollutants. Am. Ind. Assoc. J. 1977 ; 38 : 371 377. Yao C, Krueger D. A multipurpose industrial hygiene controlled atmosphere testing chamber. Am. Ind. Assoc. J. 1993 ; 54 : 313 319. - 186 -