The invention provides systems, methods and kits for the separation and/or purification of at least two cellular components selected from genomic DNA, RNA and proteins. The method includes first lysing a biological sample to generate an aqueous solution containing the cellular components; then applying the aqueous solution to a first mineral support under conditions for genomic DNA to bind; and collecting the flowthrough which contains unbound total RNA and proteins. The method further includes applying the flowthrough to a second mineral support under conditions for RNA to bind, and collecting the flowthrough which contains proteins. The genomic DNA and total RNA bound can be eluted while the protein in the flowthrough can be further purified. Further the total RNA isolated could be used to isolate small RNA such as microRNA.