摘要 以一對電極串接於石英
晶體振盪電路的回授路徑, 形成一串聯式壓電石英晶體感測系統(Series
Piezoelectric Quartz Crystal, SPQC), 系統於恆溫環境下之穩定度
為+/- 0.11 Hz/hr (24hr, 37 ''C), 其振盪頻率變化與電導增量的關係約
略呈 " S "的型態, 靈敏區間可概分為四部份 (1) <1 mS 時靈敏度0.357
Hz/uS; (2) 1 ~ 2 mS 時靈敏度 0.57 Hz/uS; (3) 2 ~ 3 mS 時靈敏度
1.43 Hz/uS; (4) >3 mS 時靈敏度 0.1 Hz/uS. 尤其是當電導範圍在 2 ~
3 mS 時, 靈敏度約高於電導度計(CDM 83, Radiometer Co., Denmark)
32 %. 鑑於系統頻率響應對電導度全域呈非線性變化之故, 實驗初始電導
值之選定對於本研究是十分重要的, 因為在高電導值的電解液情形下,
SPQC系統無法反應出微量電導度的變化. 本研究亦完成八通道SPQC的
量測系統, 可將同一試樣源置於不同條件下檢測, 我們將之分別應用於
(i) 大腸桿菌 (ATCC 25922)之定量分析, 所得之檢測極限為2.4x107
至2.4 x 101 cells/ml, 對應之頻率檢測時間(FDT)分別為98至493分鐘,
線性關係 r = - 0.988, 其 106 cells/ml 濃度之 FDT為166分鐘, 較以
導電度計法所測得之檢測時間conductance detection time, CDT)190分
鐘快12.6 %; (ii) 金黃色葡萄球菌 (ATCC 29213) 之定量分析, 檢測之
極限為1.8 x 107 至 1.8 x 101 cells/ml, 對應之頻率檢測時間(FDT)分
別為178 至 507 分鐘, 線性關係r = - 0.975; (iii) 綠膿桿菌 (ATCC
27853) 之定量分析, 檢測之極限為3.2 x 107 至 3.2 x 104 cells/ml,
對應之頻率檢測時間(FDT)分別為 395 至 551 分鐘. 亦可用於抗生素
Ampicillin 與 Ceftazidime 分別 對大腸桿菌與金黃色葡萄球菌之抑菌
能力分析探討. SPQC 的電路系統仍可繼續修改, 以擴充其量測能力(
檢測靈敏度與可靠度), 做為其它菌種定性定量分析, 抗生素抑菌能力及
臨床實體檢測之工具.關鍵詞: 串聯式壓電石英晶體感測系統, 大腸桿菌,
金黃色葡萄球菌, 綠膿桿菌, 抗生素

Abstract The home-made
series electrode piezoelectric quartz crystal system( SPQC
) was developed as a high sensitive conductive device. Under
certaincircumstance, the characteristic output frequency
depends on the conductancebetween the electrodes. Different from
a traditional conductometer, the signal( the frequency ) was
related to the conductance in a reverse sigmoid mode, and the
sensitivity is therefore superior to the traditional one
especially inthe range of 2 ~ 3 mS. The output frequency was
stable for days (+/-0.11 Hz/hr;37 ''C). The major
application of the system was to monitor the conductance
ofthe culture medium and to quantify the initial
concentration of certain microorganism existed in the samole.
Eight pairs of identical gold electrodes was assembled together
via a multi-switch, and the performance of the 8-channelSPQC
system was compared to the results obtained with a commercial
conductance meter. For Escherichia coli (ATCC 25922), the
frequency detection time (FDT)was 98 - 493 minutes with
respected to 2.4 x 107 ~ 2.4 x 101 cells/ml with the correlation
coefficient r = - 0.988; the detection time ( FDT = 166 min for
106 cells/ml) was shorter than the commercial device (
Conductance detection time, CDT = 190 min). For Staphylococus
aureus (ATCC 29213), the FDT was from 178 to 507 minutes with
respected to 1.8 x 107 ~ 1.8 x 101 cells/ml ( r = -0.975).
ForPseudomonas aeruginosa (ATCC 27853), the FDT was from 395 to
551 minutes with respected 3.2 x 107 ~ 3.2 x 104 cells/ml.
The author also used the 8-chammel system to evaluate the
antibiotic effects of ampicillin and ceftazidime onE. coli and
S. aureus. The working range and the sensitivity of the
SPQC system are continuouslyimproved to meet the other
analytical demends.Keywords: Series electrode piezoelectric
quartz crystal, Escherichia coli, Staphylococus aureus,
Pseudomonas aeruginosa, Antibiotic