Spectrophotometric determination of silicon tetrahydride in the air of workplace

Abstract

A new, simple and sensitive method was developed for the determination of silicon tetrahydride in the air of workplace in this study. The alkaline resin-based spherical activated carbon was used to collect sample of silicon tetrahydride at workplace. Silicon tetrahydride was then desorbed from active carbon in 100°C hot water. After reacting with ammonium molybdate, oxalic acid and 1,2,4-trichlorobenzene alpha-naphthol amino sulfonic acid under acid condition, silicon tetrahydride was transformed into silicon molybdenum blue. The absorbance of silicon molybdenum blue was quantitatively measured at the wavelength of 680 nm. The results showed that the average sampling efficiency and desorption efficiency were 97.53% and 94.94%, respectively by this method. Detection limits were 0.054 μg/mL for the spectrophotometric method and 0.14 mg/m³ for the determination of silicon tetrahydride in the air of workplace (sampling volume was 7.5 L). The conversion rate of silicon tetrahydride gradually decreased when storage time of samples was extended. The descent rate of sample was less than 10% when the sample was sealed for 7 days in the room temperature. It was concluded that this spectrophotometric method can be successfully used to determine silicon tetrahydride in the worksites.

Keywords

silicon tetrahydride / occupational exposure limits / determination / spectrophotometer

References

[1] KodaS. Kinetic aspects of oxidation and combustion of silane and related compounds. Prog Energ Combust, 1992, 18(6): 513-528

[2] TsaiHY, WangSW, WuSY, et al. . Experimental studies on the ignition behavior of pure silane released into air. J Loss Prevent Proc, 2010, 23(1): 170-177

[3] EremetsMI, TrojanIA, MedvedevSA, et al. . Superconductivity in hydrogen dominant materials: silane. Science, 2008, 319(5869): 1506-1509 PMID: 18339933

[4] Documentation of the threshold limit values and biological exposure indices (7th edition). American: ACGIH, 0100–2001

[5] BernhardH, MichaelP, DomenicoS, et al. . Review of the potential of silanes as rocket/scramjet fuels. Acta Astronaut, 2008, 63(1): 379-388

[6] TimmsPL. The chemistry of volatile waste from silicon wafer processing. J Chem Soc Dalton, 1999, 6: 815-822

[7] BriendP, AlbanB, ChevrelH, et al. . Method for Recycling Silane (SiH4), 2009

[8] KreigerMA, ShonnardDR, PearceJM. Life cycle analysis of silane recycling in amorphous silicon-based solar photovoltaic manufacturing. Resour Conserv Recy, 2013, 70: 44-49

[9] Centers for Disease Control and Prevention: NIOSH Pocket Guide to Chemical Hazards. (Accessed June 25, 2013 at http://www.cdc.gov/niosh/npg/npgd0556.html)

[10] Occupational Safety and Health Administration: Chemical Sampling Information. (Accessed June 25, 2013 at http://www.osha.gov/dts/chemicalsampling/data/CH_2672)

[11] MatsumuraY, OgasawaraMO, FuruseM. Analytical methods for airborne arsine, silane and dichlorosilane by adsorption sampling and AA spectrophotometry. Appl Organomet Chem, 1991, 5: 71-78

[12] MatsumuraY, MarikoONO, KomatsuT. Determination of airborne silane by adsorption sampling with modified resin active carbon and graphite furnace AAS. Ind Health, 1988, 26: 225-237 PMID: 3230055

[13] ShrewsburyRW. Union Carbide internal report: silane impurity analysis: oxygen, 1985

[14] TaylorPA. Purification techniques and analytical methods for gaseous and metallic impurities in high-purity silane. J Cryst Growth, 1988, 89(1): 28-38

[15] HiroakiT, Ibaraki. Method for the concentration determination of silane gas in a gaseous mixture, 1989

[16] Methods for examination of drinking natural mineral water: Determination of metasilicic acid in natural water for drinking. Chinese standard: GB/T8538,2008