Document Zn90wJ14eg5r75RDLmydngb07

FILE NAM E: C TFA (C TFA ) DATE: 1975 Oct 7 DOC#: CTFA014 D O C U M E N T D E S C R IP T IO N : C TFA Method Paper CTFA Method J 4-1 issued: 10-7-75 Page1 ASBESTIFORM AMPHIBOLE MINERALS IN COSMETIC TALC Part I: X-ray Diffraction Method Part II: Optical Microscopy and Dispersion-Staining Method Introduction The method which has been adopted for the detection of amphibole minerals ir cosmetic talc is the generally accepted method of x-ray diffraction. Methods which appear in the literature for the detection of fifcrous amphibole, such as, transmission electron microscopy witn selected area diffraction1 and electron microprobe,2 have aiso been considered since they are capable of a lower level of detection than by x-ray diffraction. However, they have not been adopted since they suffer from the drawbacks, that the amount of material under examination is quite small (less than a microgram) and the time for analysis, expertise required, and expense of equipment eliminates them as routine methods. The methodology presented is the most practical available, based on current technology. The use of Transmission Electron Microscopy with Selected Area Electron Diffraction offers greater sensitivity, but is not presented since it is unsuitable for normal quality control application Enrichment or concentration techniques using flotation cells have been tried as a means of improving the detection level; however, all efforts so far have been unsuccessful. Principle The x-ray diffraction method Is based upon the principle that when a crystalline material is placed in an x-ray beam, a portion of the x-rays are diffracted by each set of atomic planes within the crystal. The diffracted rays strike a scintillation counter as the sample is scanned through a prescribed angle with the resulting development of peaks corresponding to each interplanar distance (d). A peak with d value in the range of 8.04 to 8.85A0for a sample talc is strong evidence for the presence of amphibole in that talc. The level of delection of amphibole by this method Is C.5% and above. The variability of*detection Is caused by such factors as age and manufacturer of x-ray diffractometers, sample homogeneity, specific amphibole minera! present, morphology of amphibole, particle size, preferred orientation, etc. For these reasons the level of detection should be reported for levels above 0.5%, since below this level the data has been found to be not reproducible. If a statistically significant peak is found of Intensity equal to or greater than that obtained for the 0.5% standard in the d range for amphibole, described above, then the sample must be put through the foliowing confirming scheme: X-ray Diffractometry----- ( + ) j (Add Leach) Stop (Amphibole absent) Optical Microscopy -- (-) and Dispersron-Staining Color Stop (Amphibole absent) i (+) Fibrous Morphology ( - ) ^ Stop (Asbestiform Amphibole absent) I <+) Stop (Asbestiform Amphibole present) COSMETIC, TOILETRY AND FRAGRANCE ASSOCIATION, INC. - 3 1 3 3 Fifteenth Street .N.W., Washington, D.C. 20005 CTFA Method J 4*1 ssued *0*7-78 Page2 Part i; Amphibole Minerals by X-ray Diffractometry Apparatus 1. X-ray diffractometer, employing nickel-filtered copper..K-alpha radiation, horizontal or vertical goniometer with variable scan speed capability, suitable talc pellet sample holder, variable speed recorder, electronic panel including ratemeter and variable attenuation and time constant settings 2. Hydraulic press, capable of attaining a pressure of 15,000 to 24,000 lb calculated on a 3" ram 3. Mortar and pestle or grinding mill (Note 1) 4. Waring Blendor,* or equivalent blende*' 5. Spex Mixer/Mill," or equivalent mechanical mixer 6 Sieve, 325-mesh 7, Optical microscope (Note 2) 8, 1 V pellet press Reagents 1. Standard talc sample, containing no detectable amphibole minerals 2. Standard tremolite sample, at least 80% pure Sample of tremolite standard may be obtained by ordering from The Cosmetic Toiletry and fragrance Associa tion, Inc., 1133 Fifteenth Street, N.W., Washington, D.C. 20005. 3. Denatured ethanol 4. Boric acid Procedure The procedure consists of slow-scanning, under previously determined conditions, a compressed pellet of the sample talc in the 11.0 to 10,C20 (8.85 to 8.04) region for the presence of an amphibole peak. There are times when it is difficult to discrimi nate a possible peak for amphibole over the background noise level.i- i- `Registered Trademark COSMETIC, TOILETRY AND FRAGRANCE ASSOCIATION, INC. - 1133 Fifteenth Street. N.W.. Washinotnr T) C CTF Method J 4-1 Issued- 10-7-75 Pape 3 Should in e presence cl a small amphibole peak above the background "noise" be In question, it will be necessary lo statistically evaluate the scan. A :>mer/scaler Is required on the electronic panel of the x-ray diffractometer, in orcer for a peak to be statistically significant, the peak intensity must equal or exceed three standard deviations (3cr) above the average background intensity (M): Where: N + 3 a = minimum peak intensity N - average background count (T = v T T Determ ine the region of the scan in question: in the Figure 1 scan, a peak appears to be present in the 10.40 to 10.60 2 0 region. Slow scan with cumulative pulse counting through the peek region three separate tim es and average the number of counts. Determ ine a background count by scanning a region equal to of the 2 region covered by.the peak, immediately before and after the peak. T h e counting time for each of these background regions will equal the total counting time used for the peak. Count each background region three times. Then average each region and add the two averages to obtain the background count (N). COSMETIC, TOILETRY AND FRAGRANCE ASSOCIATION, INC. * 1 1 3 3 Fifteenth Street, N.W., Washington, D.C. 20005 Example: In Figure 1. Peak . . . Background Region A Region B ............. .. ......... . . . . . . ............. ............. Region (2$ 10,40 to 10.60 10.30tO 10.40 10.60 to 10.70 7/me (sec.) 120 - 60 60 Peak 10.40 to 10.60*26 time secs. counts 120 120 120 Average 60,332 59,870 60,105 60,102 Background Region A Region B 10.30 to 10.60 to10.70*26 time secs, counts time secs, counts 60 28,784 60 28.943 60 28,634 28,787 60 28,506 60 28,368 60 28,204 28,359 CTF Method J 4-1 'SSU; 10-7-76 caOfi 4 N * 28,787 + 28,359 57,146 cr= V57.146 = 239 3<r = 717 N + 3<r - 57,145 + 717 = 57,863 T h e actual number of counts obtained for the integrated peak intensity was 60,102; therefore, the "suspect" peak is statistically present in the scan. COSMETIC, TO ILETRY AND FRAGRANCE ASSOCIATION, INC. 1133 Fifteenth Street,N.W., Washington, D.C. 20005 CTFA Method d 4-1 issued 10-/-76 Ps3e5 Standard Preparation Optimal instrument conditions must first be determined with the use of tremoiite standards: 1.0%, 0 .7 5 % t 0.5 % tremoiite by w eght, prepared ir standard talc which is free of interfering peaks in the 11 .0 to 1C.Oa2 0 region. Weigh out appropriate amounts of standard laic and tremoiite both of which have been ground to pass a 025-m esh sieve. Transfer to a Waring Blendor,* Add 100 ml of ethanol to the blender and blend at low speed for 5 minutes. Carefully transfer the contents of the blender, with repeated ethanol washings, into a large beaker. Evaporate the ethanol on a steam bath* Shake the sam ple in a plastic vial for 5 minutes on a S pex Mixer/Mill* to remove clumps and caked sample resulting from the evaporation of ethanol. Dete-m ine by microscopy the homogeneity of the prpare standard previous to the x-ray diffraction analysis. Press the homogeneous standard into a V"pellet with a backing of boric acid. Transfer 2 ( tne die-holder and evenly distribute on a polished, scratch-free die. Distribute 4 ( 0.2) g of boric acid evenly on the talc layer. Press the mixture into a pellet under conditions suitable for obtaining a smooth pianar surface (tor exam ple, a pressure of 1 5 ,0 0 0 to 24 ,0 0 0 lb calculated o r a 3" ram has been found to produce suitable pellets). The resulting pellet must have a talc face which is free of flaws; if not, th e pellet must be discarded (Note 3). Prepare two acceptable pellets from each standard. Registered Trademark COSMETIC, TO ILETRY AND FRAGRANCE ASSOCIATION. INC. 1 133 Fifteenth Street. N.W.. Washington, D.C. 20005 CTFA M ethod J 4-1 issued: i0>7-7 Page 9 W eigh out 2 g of the talc into a 100 m! beaker Add 2 5 ml of 10% v/v HCI slowly (to prevent excessive evolution of gas if carbonates are present) and heat, with occasional stirring on a steam batn for 3 0 m inutes, Filterw ith vacuum filtration equipm ent, and w ash several tim es with hot w ater. Dry the talc. O ptical M icroscopy and D ispersion-Staining Carefully disperse 0.1 m g of talc in o n e drop of Cargille H D liquid, rfD5' = 1.6 0 5 , and cover with a clean cover slip. Exam ine the sam p le in the dispersion-staining central stop m ode T h e su bstage diaphragm should be alm ost co m pletely closed, the field diaphragm m ay be partially closed to e n h an ce color contrast, and the polarizer should be in position. Trem olite, actinolite and presum ably other am phibole minerals, under these condi tions, will show the following dispersion-staining colors: yellow changing to blue with rotation of the sam ple relative to th e polarizer or yellow changing to orange with rotation. T h e variation of the color ch an g e is due to th e fact that the trem olite m ay lie in one c? tw o positions relative to its principal optical orientation. Examine the sample for asbestiform fibrous amphibole minerals. In order for an am phibole m ineral to b e considered asbestiform fibrous it must meet the following O S H A definition (Reference 4). 1. Particles must ap p ea r to be fibrous rather than as crystals or slivers. 2. The maximum diam eter of a fiber to be counted in 3 microns. 3. T h e m axim um length of a fiber to b e counted is 3 0 microns. 4. T h e length to width ratio must be 5 or m ore to 1, that is, 5 tim es or m ore longer than wide. 5. The separate or individual fibers must contain fibrils or th e "bundle of sticks" effect, unless they arc at a nondivisible stage. A fibril cannot be subdivided an d would be counted, if it m eets th e other criteria. T h e length to width ratio of 5 or m ore to 1 is not m ean t to imply that other particles are not hazardous. COSMETIC. T O IL E T R Y A N D FR A G R A N C E A S SO C IA TIO N . IN C . 1 133 Fifteenth Street.N.W ,, Washington. D.C. 20005 CTFA Method J 4-1 Issued. 10-7-76 Page 10 Report pesults as "Asbesiiform Amphibole Present" or as "Asbestiforrr Amphibole Absent." It is imperative that both dispersion-staining color and fibrous morphology criteria be satisfied before identifying a particle as asbestiform amphibole, since other sub stances may show colors similar to those described. Notes 1. Talcs to be analyzed and the tremolile used to prepare standard samples must be finer than 325 mesh (m axi mum particle size of 44 microns). T h e Tekm ar Analytical Mill (Model A -10) Is recommended. It is available from: Tekmar Company P.O . Box 3 7 2 0 2 Cincinnati, O hio 45222 2. It is important that the homogeneity of the prepared taic-tremolite standarc samples be verified by optical microscopy. 3. This requirement is critical since excessive surface scatter will cause abnormally high background counts. 4. The only commercially available dispersion-staining device is sold by: W alter C. M cC rone Associates, Inc. 2620 South Michigan Avenue Chicago, Illinois 60616 5. Available from; -- or from laboratory suppliers. R. P. Cargille Laboratories, Inc. Cedar Grove, N ew Jersey 07009 References 1. Rohl, A. N., Langer, A. M., Environmental Health Perspectives 9 ,95 (1974) 2. Rubin, I. B.. Maggiore, C. J., Environmental Health Perspectives 9 , 81 (1974) 3. L. S. Birks, X -R ay Spectrochemical Analysis, pages 5 4 -5 5 , Interscience Publishers (1959) 4. "Trem olite and T a le .'1U.S. Department of Labor, Occupational S afety and Health Administration, Field Informa tion Mem orandum # 7 4 -9 2 , N ovem ber 2 1 ,1 9 7 4 . r COSMETIC, TO ILETRY AND FRAGRANCE ASSOCIATION, INC. * 1 1 3 3 Fifteenth Street, N.W., Washington, D.C 20005 C0 SMET1U TOILETTRY*! AFSMS0GCKRHWKCME1 t -- * -s *J ! ** V k Enclosed is the information which you requested. Please contact CTFA if we can be of further assistance. ! : 1133 - 15th 5T,, N.W., WASHINGTON, O.C. 20005 202/331-1770 TELEX B9-273 I m TO#