I have FACS sorted some different types of immune cells (Innate lymphoid cells, gamma delta T cells, Natural killer T cells and Natural killer cells). As the number of cells were less in number, I choose to use Qiagen WTA conversion kit (cells to Ct). I want to use Taq man assay for studying gene expression in these cells. Thermo fisher has a variety of master mix for different applications. Please suggest a master mix (Universal or gene expression master mix) that can even detect less copies of target genes.