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Title of article :
Applications of Hadamard transform-gas chromatography/mass spectrometry for the detection of hexamethyldisiloxane in a wafer cleanroom
Author/Authors :
Cheng، نويسنده , , Yuan-Kai and Lin، نويسنده , , Cheng-Huang and Kuo، نويسنده , , Samuel and Yang، نويسنده , , Jonathan and Hsiung، نويسنده , , Szu-Yuan and Wang، نويسنده , , Jia-Lin، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2012
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Abstract :
The Hadamard transform-gas chromatography/mass spectrometry (HT-GC/MS) technique was successfully employed for the detection of hexamethyldisiloxane (HMDSO, C6H18OSi2) at the sub-nL/L level in a semiconductor wafer cleanroom. Indoor air samples were collected from the room, according to EPA Method TO-17 using a Tedlar bag where the air samples were allowed to pass through an absorption tube for 24 h. The condensed components were then heated and simultaneously injected into a GC column through a Hadamard-injector, which was operated in accordance with the Hadamard codes. Compared to the single injection used in most GC/MS systems, the signal-to-noise (S/N) ratios were substantially improved after the inverse Hadamard transformation of the encoded chromatogram. Under optimized conditions, when cyclic S-matrix orders of 255, 1023 and 2047 were used, the S/N ratios of the HMDSO signals were substantially improved by 7.4-, 15.1- and 20.1-fold, respectively. These improvements are in good agreement with theoretically calculated values (8.0-, 16.0- and 22.6-fold, respectively). We found that when the HT-GC/MS technique was applied, HMDSO could be detected at the 0.1 nL/L level.
Keywords :
HMDs , Hadamard transform , GAS CHROMATOGRAPHY/MASS SPECTROMETRY , HMDSO , AMC (airborne molecular contaminant) , Cleanroom
Journal title :
Journal of Chromatography A
Journal title :
Journal of Chromatography A
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