You have to write an annotated bibliography to support your research paper, which is a literature review. This is a little different than finding sources to support your work in a lab report; you need to be thorough in your search, and you need to have a broad understanding of the context for your relatively narrow topic. 

Once you start honing in on that narrow topic, you'll spend most of your time searching the primary literature in the databases on the Articles tab of this guide. 

However, you may wish to get started by looking up some more background information about the instrument or method that you're curious about.  T

In addition to tertiary sources such as encyclopedias and handbooks, you'll also want to broaden your knowledge by searching the secondary literature which, practically speaking, means searching for review articles. You can search databases which include ONLY review articles, such as 'Annual Reviews' or you can limit your search within other databases so that you only retrieve review articles. See below. 

Example of how to limit to review articles in PubMed

Example of ProQuest Central search filtered for review articles

It may be helpful for you to get started by looking up some more background information about the instrument or method that you're curious about.  Try searching for your topic in the Gale Virtual Reference Library collection of online encyclopedias linked below.  You might try the name of the instrumental method that you're interested in (probably start broadly, with full terms rather than abbreviations, such as "chromatography" rather than "HPLC").