Page:NIOSH Manual of Analytical Methods - 7602.pdf/5

 Silica, Crystalline by IR: Method 7602, Issue 3, dated 15 March 2003 - Page 5 of 6 REFERENCES: [1]

[2] [3] [4] [5] [6] [7]

[8] [9] [10]

NIOSH [1977]. Quartz in coal dust by infrared spectroscopy: Method P&CAM 110. In: Taylor DG, ed., NIOSH Manual of Analytical Methods, 2nd. ed., Vol. 1. Cincinnati, OH: U.S. Department of He alth, Education, and W elfare, Publ. (NIOSH) 77-157-A. Talvitie NA [1951]. Determination of quartz in the presence of silicates using phosphoric acid. Anal C hem 23:623-626. Larsen DJ, von Loenhoff LJ, Crable JV [1972]. The quantitative determination of quartz in coal dust by infrared spectroscopy. Am Ind Hyg Assoc J 33:367-372. Dodgson J, W hittaker W [1973]. The determination of quartz in respirable dust samples by infrared spectrophotometry-1: The potassium brom ide disc method. Ann Occup Hyg 16:373-387. Ca res JW, Go ldin AS , Lynch JJ, B urge ss W A [19 73]. Th e dete rm ination of q uartz in airborne res pirable granite dust by infrared spectrophotometry. Am Ind Hyg Assoc J 34:298-305. Taylor DG, Nenad ic CM , Crable JV [1970]. Infrared spectra for mineral identification. Am Ind Hyg Assoc J 31:100-108. Key-Sc hwa rtz RJ, Baron PA, Bartley DL, Rice FL, Schlecht PC [2003]. Chapter R, Determ ination of airborne crystalline silica. In: NIOSH M anual of Analytical M etho ds, 4 th ed., 3 rd Suppl. Cincinnati, OH: U.S. Department of Health and Hum an S ervices, P ublic H ealth Service, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, DHHS (NIOSH) Publication No. 2003-154. Eller PM, Fen g HA, Song RS, Key-Schwartz RJ, Esc he C A, G roff J H [1999 ]. Proficiency analytical testing (PAT) silica variability, 1990-1998. Am Ind Hyg Assoc J 60(4):533-539. NIOSH [1974]. Criteria for a Recom m end ed S tandard. Oc cup ationa l Exposu re to Crystalline Silica. U.S. Department of Health, Education, and W elfare, Publ. (NIOSH) 75-120. Inhaled Particles and Vapours [1961]. Pergamon Press, Oxford, U.K.

METHOD REVISED BY: Peter Eller, Ph.D., Paul Schlecht, Rosa Key-Schwartz, Ph.D., NIOSH/DART

APPE ND IX A: INTERFERENCES Qu artz and cristobalite can be determ ined in ea ch other's presence by the use of less sensitive bands at 695 cm ! 1 (quartz) and 625 cm ! 1 (cristobalite). Tridymite can only be determined in the absence of the other two polymorphs; it is ra rely enc oun tered in industrial hygiene s am ples. Interfering silicates can be removed using a ph osp horic acid c leanup p rocedu re [2]. Cristoba lite and tridymite interfere positively at the 800 cm ! 1 peak, although they are rarely present in industrial hygiene sam ples. Kao linite, a com m on com ponent of co al, can interfere whe n RF plasm a as hing is use d to rem ove the collection filter, if it is present in sufficient quantity. A correction procedure is outlined in the method (steps 6 and 10). Calcite, at greater than 20% of the total dust loadings, can interfere by reacting with the quartz during muffle ashing. A procedure for its removal is given (step 3.b). Amorphous silica may interfere if present in large amounts. This interference can be minimized by accounting for its broad absorbance band when drawing the baseline. Qu artz is a co m m on c om pon ent of soil, rocks, sand, mortar, cement, fluxes, abrasives, glass, porcelain, paints and brick. Cristobalite is less comm on and found in volcanic rocks and soils, and can be formed in high tem perature processes such as foundry processes, calcining diatom aceous earth, brick m anufacturing, ceram ic manufacturing and silicon carbide production. Tridymite is rarely encountered, but is present in some volca nic rock s an d so ils.

NIOSH Manual of Analytical Methods (NMAM), Fourth Edition