Desenvolvimento de um detector piezelétrico para cromatógrafo a gás interfaceado a microcomputador

Química Nova

Dosil P. De Jesus¹  Gilberto A. De Medeiros¹  Claudimir L. Do Lago¹ 

[1] ,Universidade de São Paulo Instituto de Química Departamento de Química FundamentalSão Paulo SP

关键词: piezoelectric quartz crystal;    gas chromatograph;    QCM;   

DOI  :  10.1590/S0100-40421999000100020

来源: SciELO

【 摘 要 】

A piezoelectric detector based on a commercial quartz crystal of 3.57MHz is shown. A PTFE cell attached to the GC-column outlet holds the polymer-coated crystal, whose terminals were removed. Two TTL oscillators (reference and sensor) are used and the beating of their frequencies is monitored through a home-made counter card inserted in a microcomputer. The original thermal conductivity detector was also interfaced, but through a 12-bit analog-to-digital converter. In spite of the well-known fact that QCM has low sensitivity at high temperatures, results show significant peak deformation for low temperatures. In addition, the phenomenon is also dependent on the chemical composition of the absorbent film besides instantaneous partial pressure and chemical composition of the analyte.

【 授权许可】

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