Document mByRR86wD5QQbebBjoG252pB

FILE NAME: CTFA (CTFA) DATE: 1974 June 21 DOC#: CTFA021 DOCUMENT DESCRIPTION: Meeting Minutes - CTFA Task Force Methodology for the Detection of Asbestos in Talc Minutes of the meeting of the CTFA Task Force on I of Asbestos in Talc held at the Johnson & Johnson R< Present were the foUowln*? .............. .......................... ' _ " ^ 4. v . F. Robert Rolle, Task Force Ian Stewart D. Harris C. S. Thompson Dave Hamer Walter Luckewicz I John Schelz George Sandland Johnson & Job Bristol Myers 1. Mr. David Hamer discussed the most recent version of the FDA , . . , microscope method for the determination of bentos fibers in talc. The only differ ence between this method arid the earlier method is that the area of the sample to be scanned is reduced, thereby reducing the time of analysis. The method is still unacceptable, however, for all the reasons given in the December 10, 1973 CTFA report, "Report of CTFA Talc Sub-committee on Method to Detect Chrysotiie and Tremolite in Talc". 2. The Rose1 dye procedure for the detection of chrysotiie in talc has been evaluated by Dr. C. S. Thompson, and he finds it non-specific. For example, the serpentine minerals antigcritc and Uzardlte also show adsorption of the dye, He further pointed out that the method is very time consuming. Dr. T, Baak (Cyprus Ind. Minerals) in an earlier communication reported that the mineral palygorskite would act in a manner similar to chrysotiie by this method. Mr, W. Luckewicz reported that the particle size of the chrysotiie would have a dramatic effect on any attempted quanti tation of chrysotiie by this analysts. 3. The infrared method proposed by Mr. W. Luckewicz end evaluated by Bristol^ Myers has been shown to be specific for the detection of tremolite in talc. The level of detectability is about 1%by weight 4. The "cookbook" transmission electron microscope procedure of Pfizer for the detection of chrysotiie in t a l c was found acceptable, however, Mr. Ian Stewart would prefer to quantify by area count rather than "eyeballing" against a spiked standard. 5. T h e " c o o k b o o k " D i f f e r e n t i a l T h e r m a l A n a l y s is (DTA) p r o c e d u r e of Johnson &J o h n s o n a n d A v o n , for the d e te c ti o n of s e r p e n t i n e in t a l c , was accepted by the committee. T h e m i n i m u m lev el of d e te c ti o n is 0.3-1% by weight, 6. The "cookbook" x - r a y fluorescence procedure for the determ ination of tre m o lite in talc , followed by u is p e r a io n staining In the event of a positive rea d in g , was by the eon-traifctee. ?. The "cookbook" x - r a y diffra .lion method for the detection of amphlbole m inerals In tale by C y p r u s and P f i z e r was a c ce pted by the c o m m i t t e e . The lower l i m i t of d e t e c t i o n was s e t at 0 . 2 - 0 . 5% uv weight, 1 .Rose, H . A . , " Detection and Determ ination of Civvy*etilo in Talc USP", J . of -i'- CRMC-Talc-Micro-003497 to keep in only the x-ray diffraction anc this time. The "cookbook* are now available for anyone method. CRMC-Talc-Micro-003498 ffis serpentine minerals in pharmaceutical grade talc contaii less than 10% by weight chlorite, The minimum level of detection is 0.5 - 1% by weight of chrysotile asbestos. 2. The instrumental parameters must be determined for the particular differential thermal analyzer which is emplo; with regard to geometry of the sample holder, sensitivi of the differential thermocouple, e t c ., such that 0.5 by weight chrysotile may be easily detected. 3. The successful development of the OTA method is, theref based on the preparation of homogeneous chrysotile-talc standard samples. Standards containing 0.5, 1, 3, and by weight chrysotile in talc are prepared as follows: 1 'f 'V y j ' \ '!_*'< v a v % a. Five gm. of the standard talc is slurried in about 100 ml. of ethanol in a Waring Blender. The appropriate weight of chrysotile asbeBtos of at least 95% purity is then added to the talc slurry, and the mixture is blended for 5 minutes at low speed. The solution is washed into a beaker with ethanol, and the solvent is evaporatedNon a steam bath. The resulting caked sample is broken and mixed in a plastic vial by shaking for 5 minutes in a mixer such as the Spex Mixer/Mill. a. The homogeneity of the chrysotile-talc standards should be verified by optical or electron microscopy. 4. The experimental conditions, for example, for the Stone DTA unit (Models LA-XYH and RC-202C) are as follows: High temperature powder sample holder of nickel or stainless steel construction (Model SH-8RE2) with exposed-loop differential thermocouple (Platinel II) CRMC-Talc-Micro-003499 mmmmmms , , 44 microns) 7f:? ' ^ J - - ` Z', - . * , s v -. ' Inert dynamic atmosp lere: helium or nitrogen at 0.05 S - ^'U mm Heating rate: /minute Sensitivity: 40javolts full scale Furnace: LTF, water cooled to 1200C The purpose of the inert dynamic atmosphere is to p r e v -- oxidative reactions and to sweep out gaseous mineral < composition products. The Stone powder sample holder yiel maximum sensitivity by permitting direct contact of thermo couple and sample. True dynamic gas flow through the sample is also attained. It may b e possible to use a more rapid heating rate with some DTA instruments, if it can be ascer tained that constant thermal equilibrium exists between sample holder and furnace. Reproducibility of the method is based on standardizing the experimental conditions. 5. Initially, a thermogram o f the blank standard sample is run in order to determine the thermal profile of the talc. A thermogram is run on chrysotile asbestos by diluting the material approximately 1:4 in fine alumina. The thermal transitions involve a dehydroxylation endotherm at about 650C and a recrystallization exotherm at about 820C. These two peaks establish the presence of serpentine mineral. 7. The 5, 3, 1, and 0.5% chrysotile in talc standards are then analyzed. Both thermal transitions of the chrysotile in the 1% standard should be easily detectable. If not, the exper imental conditions must be altered to improve detectability. 8. Normally, pharmaceutical grade talcs will not require additional grinding for DTA, The analysis of talc rock or the presence of lumps or gritty material will, however, necessitate grinding the sample to pass a 325-mesh sieve. CRMC-Talc-Micro-003500 bottom fine alumina, or packed as a jan< thermocouple, between layers of fj case, the standard samples should the same technique to determine tl crease in peak intensities, M serpentine mineral is detected the sample must be subjected to T ence of fibrous chrysotile. If ch detected at the same level by the then the talc fails. .8 follows; V e range: ambient to 1000*C about 40 mg. talc ! Material: alumina re: static air [Models 900 CRMC-Talc-Micro-003501 This continuous y,' r P W- scanning X?., detect the prei---- a lower limit of detection of approximately 0, based upon determined conditions in the 11.0-10.029 (8.85-8.04S) region for the presence of an amphibole peak. 1 - Standard Preparation Optimal instrument conditions must first be determined with the use of tremolite standards - 1.0%, C.5%, 0.25%, tremolite by weight prepared in a standard talc which is free of interfering peaks in the 11.0-10.028 region. The tremolite aisa standards are prepared in the following maimer: a. Weigh out appropriate amounts of standard talc and tremo lite of at least 95% purity, both of which have been ground to pass a 325-mesh sieve. Transfer to a Waring Blender (or equivalent). Add 100 ml. of ethanol to the blender and blend at low speed for 5 minutes. CRMC-Talc-Micro-003502 ifP tfS fp lil iSiWi alumina : Inert dynamic atmosphere: he3 Heating rate: 10C./minute . Sensitivity: 40 Furnace: LTF, water -- -- -- ------- -- The purpose of the inert oxidative reactions and to sweep out composition products. The Stone powder sample holder yields maximum sensitivity by permitting direct contact of thermo- couple and sample. True dynamic gas flow through the sample is also attained. It may be possible to use a more rap heating rate with some DTA instruments, if it can be ascer tained that constant thermal sample holder and furnace.. _______ ;___ _ fm e t h o d is based on standardizing the experimental conditions. 5. Initially, a thermogram of the blank standard sample is run in order to determine the thermal profile o* the talc. 6. thermogram is run on chrysotile asbestos by diluting the material approximately 1:4 in fine alumina. The thermal transitions involve a dehydroxylation endotherm at about 650c and a recrystallization exotherm at about 820C. These two peaks establish the presence of serpentine mineral. 7. The 5, 3, 1, and 0.57, chrysotile in talc standards are then analyzed. Both thermal transitions of the chrysotile in the 1% standard should be easily detectable. If not, the exper imental conditions must be altered to improve detectability. 8, Normally, pharmaceutical grade tales will not require additional grinding for DTA. The analysis of talc rock or the presence of lumps or gritty material will, however, necessitate grinding the sample to pass a 325"mesh sieve. CRMC-Talc-Micro-003503 Mil case, the s creasi If serpi the saw enee of 990) would be as follows; >ut 40 mg. Heating rate; 30 C CRMC-Talc-Micro-003504 b . Carefullytransfer contents of ethanol on a C. The dried sample is then shaken for 5 minutes oi ' ., ' . ... ... : .. / Miscer/Mill or equivalent to remove clumps and caked resulting from the evaporation of ethanol. e. The homo*geneous sta: n d....a. rd is pressed into a 1%'* pellet hacked with boric acid. 2 gram of standard is transferred : ........ to the die-holder and evenly distributed on a polished; - scratch-free die. 4 gram of boric acid is then distributed evenly on the talc layer. The mixture is pressed into a pellet under a pressure of 24,000 lb. (calculated on a 3" rsm) for 5-10 minutes. The resulting pellet must have a talc face which is free of flaws; if not the pellet must be discarded. (This requirement is critical since excessive surface scatter 'ill cause excessively high background counts.) Three acceptable pellets are prepared from each standard. 2 - Sample Preparation Three pellets are prepared from each sample in the manner described for the standard pellets (l.Step e.). A CRMC-Talc-Micro-003505 ilil the presence of mineral Impurities ] i n the 11.0-10.029 <8.85-8.048) rei ` ' ,! ' 5 , - V-"' fr ', a: presence of the latter will elimin* for the sample. Lower standards are then analyzed under the to determine t h e l o w e r level of detection. in obtaining maxi m u m instrument sensitivity are a slow diffr. taneter speed combined with a compatible recorder speed and hi, -- attenuation with a statistically acceptable time constant on the ratemeter. Xnstnsnental conditions employed for the Siemens Diffractomet (Model No. K3S6- X - A 4 ) , and counter and Recorder Unit (Type T) are: Radiation: Gu with KB filter at 40 KV and 24 Ma Divergence slit: 1 Receiving slit: 0.2 mm Goniometer speed: 1/1029/minute Recorder speed: 300.mm/hr Attenuation 4 x impulses/second Statistical Time constant,. T<*) - 10 error of 1.1% - under these conditions. Rise Time - 0.18 Attenuator 20 x . ... ..'*9i CRMC-Talc-Micro-003506 4 - X-Ray Procedure The pellet is pieced in * aultehle X-ray holder i slow-scanned from ll.0-10.02d. All three peliete can in this manner. The presence of a reproducible peak < between 10.75 and 10.1029 (8.75-8.25S) is due to til* presence of amphibole mineral(s) in the talc. Xdentii of an amphibole mineral aa tremolite oust be performs* optical mlcrescopy/dispersion staining or electron mi< A typical scan for a 0.257 tremolite in talc standard Is included. CRMC-Talc-Micro 003507 EJ* JFU I From: F Copies: R Subject: Winthrop Laboratories Rensselaer, New York Your Letter 6/17/74 12144 The paper "Detection of Chrysotile in Talc" one Harry Rose of Eli Lilly. It reports on detecting chrysotile by dye adsoi inspection. The chrysotile is st adsorb the dye in preference to . Our`expert in detection of chrysotile in at Jim Leineweber of Research and Development. From him, I learn that chrysotile from different sources adsorbs dyes differently-- and so do talc from different sources. The article describes work with carefully selected pure chrysotile and pure talcs. We would not regard the proposed technique as reliable as a standard test for all types of talc or chrysotile. Detection of chrysotile by X-ray defraction would be more., , .. reliable, and is easier to perform if you have the equipment. Low levels of chrysotile in talc can be measured only microscopically-- and an electron microscope is necessary. If Mr. Ellis wants more detailed information or amplification of this brief comment, I suggest you have him call Leineweber, (303) 770-1000, Ext. 83-553. T. M. Jackson TMJ:ccr CRMC-Talc-Micro-003509