Bedwell C L, Hamar D W, Hoesterey M L, Sonderman J P, Odde K G
Diagnostic Laboratory, College of Veterinary Medicine and Biomedical Sciences, Colorado State University, Ft. Collins 80523, USA.
J Vet Diagn Invest. 1995 Oct;7(4):527-30. doi: 10.1177/104063879500700418.
Twenty forage samples were collected and selected for variation in nitrate content. Each forage samples was analyzed 4 times by 4 different methods: diphenylamine spot plate, spectrophotometric, nitrate-selective electrode, and high-performance liquid chromatographic. Five feed extracts were spiked with 2 different amounts of nitrate and analyzed by each method. The spectrophotometric and nitrate-selective electrode had similar percent recoveries, which were close to 100%. The nitrate-selective electrode method had the least variation of the 4 methods. The diphenylamine spot plate method had the poorest average recovery, greatest variation, and was the least accurate. The average coefficients of variation for all samples within a method were 15%, 12%, 6.4%, and 16 for the diphenylamine spot plate, spectrophotometric, nitrate-selective electrode, and high-performance liquid chromatographic methods, respectively. The variation in the nitrate-selective electrode method was lower (P < 0.05) than the other methods. The results from this study suggest that the nitrate-selective electrode method is more accurate and precise than the other methods of analysis tested.
收集了20个草料样本，并根据硝酸盐含量的差异进行了挑选。每个草料样本通过4种不同方法分析4次：二苯胺点滴板法、分光光度法、硝酸盐选择性电极法和高效液相色谱法。向5份饲料提取物中加入2种不同量的硝酸盐，并通过每种方法进行分析。分光光度法和硝酸盐选择性电极法的回收率百分比相似，接近100%。硝酸盐选择性电极法在这4种方法中变化最小。二苯胺点滴板法的平均回收率最差，变化最大，准确性最低。二苯胺点滴板法、分光光度法、硝酸盐选择性电极法和高效液相色谱法中，各方法内所有样本的平均变异系数分别为15%、12%、6.4%和16%。硝酸盐选择性电极法的变异低于其他方法（P<0.05）。本研究结果表明，硝酸盐选择性电极法比所测试的其他分析方法更准确、更精确。
