low RNA content despite high A260/280 Ratios

[Thomas Mohr]

Dear colleagues,

recently we observed a high A460/A280 Ratio (>2.0) but a
formamide-gelelctrophoresis revealed very low contents of ribosomal RNA.
We did not observe signs of degradation (smears, etc).

The RNA was isolated by treatment with RNAzol, followed by an
Chloroform-Isopropanol-ethanol extraction.

Does anybody have an idea what might have gone wrong, resp. why this
high rations occured ?
Any response to thomas.mohr at utanet.at would be greatly appreciated.
Thanks,
Thomas