Zeta’s Citrate Plus (10X) HIER Solution is a unique citrate buffer designed to significantly enhance immunohistochemical staining with many commercially available primary antibodies. Diluted 1:10 with deionized or distilled water, this product is easy to use and highly effective. Citrate Plus (10X) can be used in a vegetable steamer, autoclave, or pressure cooker. However, for optimal results we recommend the autoclave or pressure cooker.