总 RNA 制备:A260 = 0.4,1:5 稀释 1:5 稀释的总 RNA 制备在 1 cm 比色皿中测得 A260 = 0.4。浓度 = 0.4 × 5 × 40 ÷ 1 = 80 µg/mL,即 80 ng/µL RNA。250 µL 洗脱液共含 80 × 0.25 = 20 µg——约够 20 次常规 qPCR 的投入量,读数也在 0.1–1.5 线性范围内。若误用 dsDNA 的系数 50,会错误地算出 100 µg/mL。{"result":"RNA concentration = 80 µg/mL (80 ng/µL); total 20 µg in 250 µL.","metadata":{"input":{"a260":0.4,"dilutionFactor":5,"pathLengthCm":1,"sampleVolumeUl":250},"result":{"constantUgMlPerOd":40,"concentrationUgMl":80,"concentrationNgUl":80,"totalUg":20,"measurementQuality":"within linear range (0.1–1.5)"}}}
未稀释 RNA 样品测得 A260 = 0.08,低于线性范围约 0.1 的下限——噪声在信号中占比可观。工具仍算出 0.08 × 1 × 40 ÷ 1 = 3.2 µg/mL(3.2 ng/µL)、50 µL 中 0.16 µg,但会标记该读数,提示降低稀释倍数复测(或改用对低浓度更灵敏的荧光法定量)。{"result":"RNA concentration = 3.2 µg/mL (3.2 ng/µL); reading below the linear range — re-measure less diluted or use a fluorometric assay.","metadata":{"input":{"a260":0.08,"dilutionFactor":1,"pathLengthCm":1,"sampleVolumeUl":50},"result":{"constantUgMlPerOd":40,"concentrationUgMl":3.2,"concentrationNgUl":3.2,"totalUg":0.16,"measurementQuality":"below linear range — reading too low for reliable quantitation, measure a higher concentration or a shorter dilution"}}}