Hello Nosaibah Alakkam

Exosomes typically yield total RNA in the range of 3-12ng/ml. Depending on the source of the starting material and the concentration of exosomes, the RNA concentration may vary. Moreover, exosomes are a heterogeneous population of vesicles with widely varying cargo in which some vesicles may have RNAs while some exosomes may carry only the protein cargo and no RNA.

So, depending on the sample type and the exosome concentration, the RNA yield may vary.

Regarding purity..

The 260/280 ratios are routinely used to determine the purity of nucleic acid measurements. This ratio is used to determine the presence of protein and or phenol in the isolated nucleic acid sample. For RNA, the 260/280 ratio should be ~2.0. You have recorded the 260/280 ratio as 1.6 which means possible contamination with acidic phenol or protein.

The 260/230 ratio is used to indicate the presence of unwanted organic compounds such as Trizol, Phenol, Guanidine HCL and Guanidine thiocyanate. Generally, acceptable 260/230 ratios are in the range of 2.0 – 2.2. You have recorded the 260/230 ratio as 0.1. If the ratio A260/230 is appreciably lower than expected, it may indicate the presence of contaminants which absorb at 230 nm.

So, you may have to improve upon the RNA isolation technique.

Best.