Musc9e Liver Heart Brain Brain Liver Heart Breast muscle Shanks and tot.\
h
,
Aveiage of b o diquots.
* Not determined
metabolites, although these have been previously reported only in liver and feces (Abou-Donia and Mcnzel, 1968). T'hc lower recoveries obtained after Florid and thin-layer chromatography illustrate the losses due to co~stiliationthat can occur in virtually fat-free samples evaporated to near or cornplete dryness under an air stream (Burke, Mills, et 01.. 1966). Scanning of the zone eluates by gas c ~ r o m a t o g r a p ~revealed y p,p'-DDT as the principal compound present, with lesser amounts of p,p'-DDD and DDE. The percentage recoveries for dieldrin are given in Tabk I. Depending on the tissue, duplicate variability in the counts of samples solubilized with perchloric acid and hydrogen peioxide rdngecl from 7-30%, and counts in an aliquot ofSo,xhlet extract exceeded those in an equiVahK weight of solubilized tissue by lO-lOS%. Use of a quaternary base (Soluene) as ;t solubilidng agent did not improve recoveries. These resuits suggest that dieldrin was partially volatilized and lost ituring solubilization; thus. all stepw'se recoveries are related in Table I to courits in the Soxhkt extracts rather than to L!OW in solubilized tissues. As with DDT, mine dieldrin was lost by
Sydney C. Barton and Nenr) G . MsAdie Ontario Research Foundation, Shcridan Park, Oiitario. Canada
A method for reducing blank effects in the collection of HBO? aerosol on glass fiber filters has been developed. 'Treatment with hot HzSOI foliowed by thorough rinsing permits the filters to be used to collect microgram amounts of H&04 aerosol without any significant irreversible lass of H$Oc on the filter.
G
lass fiber filters combine the desirable features of high retention efficiency of submicron particles with high flow rates, and so have found widespread use in the collection of particulate samples in air pollution studies. Such filters were used extensively for the collection of HnSor aerosol until i t
was shown (La: nn3 Wagman, 1966) thai atniospheric sulfur dioxide could be oxldired catalytically on rhe glass surface and thus sei iotsl? interfere with the deternunation of prevailing HSO, aerosol levels. Dilticulties encountered in allowing for blank efFects when .tnaljzing f x H SOt aerowl collectcadon gla5s fiber filters have also been discussed Druboih, Tachman, el id. (1967)report that inany brands of thcse filter5 containeil excessively high amounts of sullblsr tnd have de\crhed extraction proaxfurs bq which thew .,in be reduced. Howewr, Scaringelli and Rehme (1969) w c l r h t the rcsidual alkali content of the filter can result in s d f w I C acid losses of 0.4 to 7 8 pg per cm. 2 of filter. Thus. there c a n he considerable vanation in the chemical propertie.; oi' plais f i k r tilters. anti t low ~ t t ~ mmt ~ ~ j ~ n be given to hEanl, effects when dcaliq; with a t ~ o ~ wnples contcimng micr
acid treatment for the rtmoval of rrsidual alkali from iiltrr\ to
be umi for the collection ofN&Ocewrosol. Work in this 1,iboratory has required N method for the rffkrent collection and analjsis of could be n L h i o r i 1 u h e n solctw.i umiitining 15 pg. of H W , In 2 nil. of IJ 0 u,is ,ipplird to ct J?-mm. filter and subrequently extracted w i t h hoc': rwpropsnol. Attempts to increiise t b iecoverj b y exrr,iiiing the filter with boiling water rdther t h m SOq, mix ~ p i n owere i not successfu!. Instead, thi\ resulted in i~slrg11:ij loMcr rrcoverq of H S O i from the filter. This suggebted thdt titwnient of the filter. I . E . , with exce4s hot H S O , . follonrd by ,I thorough washing, might be ,i way to iteaLtivLite dn) wfc+ce contdrninants which could be respomible tor thc apparent irrever:xable absorption of sulfuric c t ~ i dA proceJmrc was developed 111 which filters are soaked in ?Or; sulfurrc 'lad for 2 to 3 days at room temperature, brought slow1> to R gentle hoil for 10 min , and then repeatedly rinsed in distdled water. 80% isopropanol and, finallj, acetone. Care I \ tdhen not to bend or fold the filters while wet IO pre\enr ptmidnent fractures After the filters are air-dried, they are stored in :I desiccator dt a constant rzlatne humidity of 45 r; To test the effectiveness of this prowlure In ,-ctinparr\i?n with that of Scaringeili, Bcwne, tv ul (IW),7-ml : I ! I C ~ L ~ X ~ of standard HtSO, solutions containing 3 to 9 ug H-SO, W I ~ ' applied to filten treated in different ways and the measured recoveries are s u m m a z e d in Table 1. No i o h m of tt-SO, i 4 ~ w observed with filters treated as described above, zo t h d s u h fifters can be used to collect microgram amounts of c.:tniospheric HiSOc arrow1 for subsequent an,tlysi\ b) the odr1iiiii chloranrlate method. Thc. &SOl treatnient would be expected t o chdrigt" on!) the surftice of the g l a s fibers wilhoul causing an) mijor cisruption in the filter's fibrous structure which might r r d t in 'i 10% of retention elticiencp. An H$04-treLited tiller ,ind it blillipore Sol-jinert filter (0 5-p pore size) ',$ere iict":j in si.rie\ to collect H S O l aerosol having a mas> median d i m e t a c7f 0.6 p No sigruficant amount of H$O, uas detected on the Snlvinert filter, conFrming that the retention efficient! of tht. gldss fiber filter was not decreased by the H2S04treatmcnr
