I need to quantify the total miRNA in my sample in order to calculate the volume that should be used for microarray analysis. can I use small RNA chip/agilent in my case??
There are different options. 1st you can quantify the total RNA amount with a very sensitive system (fluorescence based) and extrapolate the quanity of miRNAs in the sample. 2nd you can use small RNA chips. However, both systems are not precise enough. I recommend the first option if you know well your sample type; if you know the percentage of miRNAs exist in your samples.
I agree with Albert. My choice would be to use a capillary electrophoresis system (Bioanalyzer or similar). For microarray analysis you normally will start with total RNA preparations, and calculate the total RNA concentration.
I do not think that you should need to quantify the amount of miRNAs. Moreover, the quantification of total miRNA amounts is very difficult because they will appear as a low-molecular weight peak, which is also contaminated with tRNAs and other small RNAs.