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Submitted to: Meeting Abstract
Publication Type: Abstract Only Publication Acceptance Date: 6/23/2006 Publication Date: 11/13/2006 Citation: Chen, G. 2006. Led-based portable tetracycline-specific analyzer. Optic East 2006 Proceedings. Interpretive Summary: Technical Abstract: Tetracycline (TC) is a significant class of antibiotic drugs widely used in human and veterinary medicine. Field instruments and methods are in demand for its analyses in food, biological, clinical, and environmental matrices. To serve such needs a TC-specific analyzer was developed based on europium-sensitized luminescence. A 385 nm UV LED provides selective excitation replacing a xenon flashlamp. Its narrow emission and low residual radiation significantly reduces background signals. The time-resolved luminescence (TRL) is detected by a photomultiplier tube (PMT) and digitized at a 4-µs time resolution and a 12-bit amplitude resolution. The PMT is gated to effectively reject early emission components. The fluctuation in LED pulse energy is monitored and corrected by integrating the photodiode current of individual pulses. The instrument operation and data processing are controlled by a custom LabVIEW program. This analyzer achieves a 0-2 ppm linear dynamic range (r2 = 0.994) with a 0.27-ppb limit of detection. Sensitivity is further improved by 1-3 orders of magnitude by SPE enrichment using 3M Empore C18 disks. Besides liquid-phase measurements, TRL can also be measured directly on C18 sorbent surfaces after extraction and enrichment, providing a simple and low-cost method friendly to workers and the environment. |
