. Many of the biotin labeling kits from Pierce use an NHS-Biotin reagent WITHOUT the chromogenic fluorophore. Using a chromogenic biotin reagent offers MANY advantages…you can use simple UV quantitation to determine biotin incorporation – with no need for the HABA assay, an additional assay required to determine the extent of biotin incorporation. There are several other advantages as well, which are listed on our website. We offer a variety of formats of this reagent – both in kits and as standalone products. TriLink’s biotin product page provides an overview of our product offerings. If you perform a significant amount of biotin labeling, one of these other options may work well for you. Another consideration: we can provide you with a much higher level of technical support than can Pierce. As the inventor and developer of this reagent/technology, and having years of experience with custom conjugations and product development, we can better assist you with your projects and help you optimize biotin labeling for any of your applications. Also, we can offer discounts to you for volume purchases – either in kit format or in any custom packaging for your company.