Murnick Daniel E, Dogru Ozgur, Ilkmen Erhan
Department of Physics, Rutgers University, Newark, New Jersey 07102, USA.
Anal Chem. 2008 Jul 1;80(13):4820-4. doi: 10.1021/ac800751y. Epub 2008 Jun 6.
We show a new ultrasensitive laser-based analytical technique, intracavity optogalvanic spectroscopy, allowing extremely high sensitivity for detection of (14)C-labeled carbon dioxide. Capable of replacing large accelerator mass spectrometers, the technique quantifies attomoles of (14)C in submicrogram samples. Based on the specificity of narrow laser resonances coupled with the sensitivity provided by standing waves in an optical cavity and detection via impedance variations, limits of detection near 10(-15) (14)C/(12)C ratios are obtained. Using a 15-W (14)CO2 laser, a linear calibration with samples from 10(-15) to >1.5 x 10(-12) in (14)C/(12)C ratios, as determined by accelerator mass spectrometry, is demonstrated. Possible applications include microdosing studies in drug development, individualized subtherapeutic tests of drug metabolism, carbon dating and real time monitoring of atmospheric radiocarbon. The method can also be applied to detection of other trace entities.
我们展示了一种基于激光的新型超灵敏分析技术——腔内光电流光谱法，它对检测含（14）C标记的二氧化碳具有极高的灵敏度。该技术能够替代大型加速器质谱仪，可对亚微克样品中的（14）C进行阿托摩尔级的定量分析。基于窄激光共振的特异性，结合光学腔内驻波提供的灵敏度以及通过阻抗变化进行检测，可实现接近10^(-15)（14）C/（12）C比值的检测限。使用一台15瓦的（14）CO2激光器，通过加速器质谱法测定，对（14）C/（12）C比值在10^(-15)至>1.5×10^(-12)范围内的样品进行了线性校准。其可能的应用包括药物研发中的微剂量研究、药物代谢的个体化亚治疗测试、碳年代测定以及大气放射性碳的实时监测。该方法还可应用于其他痕量物质的检测。
