小提 50 ng/µL、5000 bp 质粒 → 9.12×10⁹ 拷贝/µL 测得 50 ng/µL、骨架 5,000 bp 的质粒小提换算为 50×10⁻⁹ g/µL ÷ (5,000 × 660 g/mol) × 6.022×10²³ = 9.12×10⁹ 拷贝/µL,即 0.015 pmol/µL。向 50 µL qPCR 加入 2 µL 即投入 1.82×10¹⁰ 个模板分子——远高于标准曲线保持线性的 10⁴–10⁷ 拷贝区间,十分富余。{"result":"50 ng/µL of 5000 bp DNA = 9.12e9 copies/µL (0.0152 pmol/µL); 2 µL holds 1.82e10 copies.","metadata":{"input":{"concentration":50,"concentrationUnit":"ng/µL","templateLengthBp":5000,"volumeUl":2},"result":{"copiesPerUlMantissa":9.12,"copiesPerUlExponent":9,"pmolPerUl":0.0152,"totalCopiesMantissa":1.82,"totalCopiesExponent":10}}}
λ DNA 标准:48,502 bp、10 ng/µL → 1.88×10⁸ 拷贝/µL 经典定量标准品:λ DNA 全长 48,502 bp,10 ng/µL 工作液含 10×10⁻⁹ ÷ (48,502 × 660) × 6.022×10²³ = 1.88×10⁸ 拷贝/µL(0.0003 pmol/µL)。本例展示基因组尺度——长模板使每 ng 的拷贝数比 5,000 bp 质粒低三个数量级——也说明标准品稀到这个程度时需要相当于 pg/µL 级的灵敏度。{"result":"10 ng/µL of 48502 bp DNA = 1.88e8 copies/µL (0.0003 pmol/µL).","metadata":{"input":{"concentration":10,"concentrationUnit":"ng/µL","templateLengthBp":48502,"volumeUl":0},"result":{"copiesPerUlMantissa":1.88,"copiesPerUlExponent":8,"pmolPerUl":0.0003,"totalCopiesMantissa":null,"totalCopiesExponent":null}}}