一批里面总有失败的？？？你是配置的反应mix，分装后单独加的RNA进行反映的嘛？

你可以试一下这个方法
First-Strand cDNA Synthesis Using SuperScript™ II RT
A 20-μL reaction volume can be used for 1 ng–5 μg of total RNA or 1–500 ng
of mRNA.
1. Add the following components to a nuclease-free microcentrifuge tube:
Oligo(dT)12-18 (500 μg/mL) or 1 μL
50–250 ng random primers or
2 pmole gene-specific primer (GSP)
1 ng to 5 μg total RNA or x μL
1–500 ng of mRNA
1 μL dNTP Mix (10 mM each) 1 μL
Sterile, distilled water to 12 μL
2. Heat mixture to 65°C for 5 min and quick chill on ice. Collect the
contents of the tube by brief centrifugation and add:
5X First-Strand Buffer 4 μL
0.1 M DTT 2 μL
RNaseOUT™ (40 units/μL) (optional)* 1 μL
*RNaseOUT™ (Cat. No. 10777-019) is required if using <50 ng starting RNA.
3. Mix contents of the tube gently. If you are using oligo(dT)12-18 or GSP,
incubate at 42°C for 2 min. If you are using random primers, incubate at
25°C for 2 min.
4. Add 1 μL (200 units) of SuperScript™ II RT and mix by pipetting gently
up and down.
If you are using less than 1 ng of RNA, reduce the amount of
SuperScript™ II RT to 0.25 μL (50 units) and add sterile, distilled water to
a 20 μL final volume.
If you are using random primers, incubate tube at 25°C for 10 min.
5. Incubate at 42°C for 50 min.
6. Inactivate the reaction by heating at 70°C for 15 min.
--------来着易基因的回答，