双标水法：实验室之间的稳定同位素测量对比

双标水(doubly labeled water,DLW)法是研究动物野外能量代谢最准确的方法,其中最关键、最困难的环节是同位素的定量分析。为了检验不同同位素实验室测定动物血样氢氧同位素丰度的准确性及其对估算能量代谢的影响程度,成都地质学院(CCG)和美国加利福尼亚大学洛杉机分校(UCLA)的同位素实验室于1990年5月开展了合作,以成都附近农村的5只山羊为研究对象进行了双标水法的实验。将采集的动物血样分别在两个实验室进行了D和~(13)O含量测定,取得了成功的结果:两个实验室所测得的~(13)O值近于相同,而UCLA同位素实验室测得的~(13)O值略高于CCG的测定值。由此所计算出的能量代谢值却非常接近,其差值平均为6.6％;水循环平均相差1.2％,差异均不显著(P>0.05)。UCLA实验室的质谱仪已为英国和荷兰的同类实验室所校正,这确认了我们的合作测定成果的可信度和有效性,证明CCG和UCLA实验室的测定结果均可以满足双标法同位素定量测定的需要。测定结果是可信的。本文还就两地实验室所测结果产生误差的原因进行了初步分析,对于进行同类研究的其它实验室也有借鉴意义。

THE DOUBLY LABELED WATER METHOD:INTER LABORATORY COMPARISON OF STABLE ISOTOPE MEASUREMENTS

Doubly labeled water (DLW) method is the most correct method for measuring energy of wild animals, and the most difficult key in the method is the quantitative analysis for isotopes of body water in animals. For testing reliability of isotope measurements in different laboratories, the Chengdu College of Geology (CCG) and- the University of Colifornia at Los Angeles (UCLA) had cooperated on measureing identical blood samples taken from doubly labeled goats living near Chengdu in May of 1990, and got a successful result. The deuterium values from each laboratory were neary identical, but the 18O results from UCLA were consistently higher than those from CCG. However, the energy metabolism values determined by each aboratory were very similar. Metabolic rate valurs differed between laboratories by 6.6% on average, and water influx rates differed by an average of 1.2%, but neither difference is statistically significant.Because the UCLA laboratory has been caibrated against laboratories in United Kingdom and in the Netherland, the determined results in the isotope laboratoies in CCG and UCLA have been validated for DLW method.This paper tries to discuss the error source in the different laboratories, and has a reference significance for the similar laboratories.