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Submitted to: British Journal of Dermatology
Publication Type: Proceedings Publication Acceptance Date: 9/14/2006 Publication Date: 11/20/2006 Citation: Chen, G. 2006. Led-based tetracyline analyzer for field analysis. Proceedings SPIE. 6377. Interpretive Summary: Technical Abstract: Tetracycline (TC) is a significant class of antibiotic drugs widely used in human and veterinary medicine. Sensitive and selective instruments and methods are in demand for its analyses in clinical, food, biological, and environmental matrices. Many of these tasks must ideally be performed in the field. To serve such needs, we developed a portable tetracycline analyzer capable of time-resolved luminescence measurements. A 385 nm UV LED is used to selectively excite the TC analytes. Its narrow bandwidth and low residual radiation allow improvements in background performance over a xenon flashlamp. TC forms a complex with Eu in the reagent solution; and its long-lasting luminescence is detected by a photomultiplier tube (PMT) and digitized at a 4-µs time resolution and a 12-bit amplitude resolution. Both instrument operation and data processing are controlled by a laptop computer running a custom LabVIEW program. The analyzer can be configured for two operation modes: (A) liquid-phase measurement using a sample cuvette, and (B) solid-matrix measurement on a sorbent surface after TC extraction and enrichment. The performance of this analyzer is evaluated using oxytetracycline as a model analyte. In configuration A, a 0-3 ppm linear dynamic range (LDR) (r2 = 0.997) and a 0.25-ppb limit of detection (LOD) were achieved with a typical 10% relative standard deviation (RSD). In configuration B, a 0-100 ppb LDR (r2 = 0.999) and a 0.13-ppb LOD were achieved after 1-hour extraction with a typical 5% RSD. |
