SILICA, CR YST ALLINE , by XRD: M ETH OD 7500, Issue 4, dated 1 5 Ma rch 2003 - Page 7 of 9 R T îAg ÎAog
= = = =
sin (1 Ag)/sin (1 x) îAg/(average ÎAog) = transm ittan ce of s am ple norm alize d silver pe ak intensity fro m sam ple normalized silver peak intensity from m edia blanks (average of six values)
EVALUATION OF METHOD: This method is based on P&CAM 259 which was collaboratively tested [1]. The testing included a ruggedization step to test the effects of the use of muffle furnace or plasma asher (but not the use of TH F), shipment of samples, ashing time, and ultrasonication time. None of these factors was found to have an effect. The m ethod was shown to have no bias when referenced to the Talvitie spectrophotometric method [14] and when all standards and sam ples were M in-U-Sil 5. The relative standard de viations (S r) for intralaboratory, total measurem ent and overall (including sampling) variability are:
Analyte Level (µg)
Measurement Precision (S r)
Intralaboratory
50-200 20 10
0.08 [1] 0.20 [5] 0.28 [9]
Total (intra- and inte rlaboratory)
50-200
0.17 [1]
Overall Precision (S rT)
0.29 [1]
REFERENCES: [1] [2] [3] [4]
[5] [6] [7]
[8] [9] [10] [11]
[12] [13]
Anderson CC [9183]. Collaborative tests of two m eth ods for determ ining free silica in airborne d ust. U.S . Departm ent of He alth an d Hum an S ervices, P ubl. (N IOS H) 8 3-12 4. NIOS H [1983]. Use r check , UBT L, NIOS H Se quenc e #4121 -M (unpu blished) NIOSH [1974]. Criteria for a Recom mended Stand ard: O ccu pation al Expos ure to Crystalline Silica. U.S . Departm ent of He alth, Ed uca tion, and W elfare , Pub l. (NIO SH ) 75-120 . NIO SH [1979]. Silica, crystalline: Method P&CAM 259. In: Taylor DG, ed., NIOSH M anual of Analytical Methods, 2nd ed., Vol. 5. Cincinnati, OH: U.S. Department of Health, Education, and W elfare, Publ. (NIO SH ) 79-141 . Ibid, Vol. 3, S315. U.S. Department of Health, Education, and W elfare, Publ. (NIOSH) 77-157-C (1977). NIOSH [1977]. Documentation of the NIOSH Validation Tests. S315, U.S. Department of He alth, Educa tion, an d W elfare , Pub l. (NIO SH ) 77-185 . NIOSH [1977]. Silica (XRD): Method P&CAM 109. In: Taylor DG, ed., NIOSH Manu al of Analytical Methods, 2nd ed., Vol. 1. Cincinnati, OH: U.S. Department of He alth , Ed ucatio n, and W elfare, P ubl. (NIO SH ) 77-157 -A. Bu m ste d H E [1 973]. D ete rm ination of a lpha-quartz in the res pirable portion of airborne particles by Xray diffraction. Am Ind Hyg Assoc J 34:150 . Peters ET [1976]. Evaluation of the NIOSH X-ray diffraction method for the determination of free silica in respirable dust. Final Report, NIOSH Contract CDC-99-74-51. Eller PM, Feng HA, Song RS, Key-Schwartz RJ, Esche CA, Groff JH [1999]. Proficien cy a na lytical testing (PAT) silica variability, 1990-1998. Am Ind Hyg Assoc J 60(4):533-539. Key-Sch wartz RJ, Baron P A, B artley DL, Rice FL, Schlecht PC [2003]. Chapter R, Determination of airborne crystalline silica. In: NIO SH Ma nua l of Analytical Metho ds, 4 th ed., 3 rd Suppl. Cin cinnati, OH: U.S. Departm ent of He alth and Human Services, Public Health Service, Centers for Disease Control and Prevention, National Institute for O ccu pation al Safety and Health, DHHS (NIOSH) Publication No. 2003-154. Inhaled Particles and Vapours [1961]. Pergamon Press, Oxford, U.K. Kupel RE , Kin ser RE, M auer PA [1968]. Se paration and analysis of the less than 10-micron fractions of industrial dusts. Am Ind Hyg Assoc J 29:364 .
NIOSH Manual of Analytical Methods (NMAM), Fourth Edition
