rna cleanup problems

[nageshki]

hej everybody,
i have extracted total rna from 24 well plate mono layer cultures by using trizol method. the amount isolated is good but the quality 260/280 is between 1.4 to 1.7 only but the 260/230 ratio is less than 0.5. so i tried to clean up the rna by using qiagen rneasy mini and rneasy microkit and zymoresearch's rna clean and concentrator. after cleaning i am unable to see the rna and the nanodrop is showing negative results indicating absence of rna. all the three methods have shown the same. i am sure that rna is present in the sample because before cleaning i again checked the rna values in nanodrop. could anyone suggest me what is the problem and how to rectify and how to remove the protein contamination as indicated by 260/230 ratio.
thanks in advance.