There are quite a few free tools on the web to help you use HPLC effectively. I have chosen seven tools to share with you in this blog that I think should prove useful, in no particular order of preference. Please let me know if there are any others that you think should have been mentioned and I’ll include them in a future blog.
1. HPLC Troubleshooting Guide by Uwe Neue
This excellent troubleshooting guide by the late Dr. Neue takes the form of a series of questions and answers, where each topic starts off with a question describing a particular problem and the answer suggests a possible solution. This is then followed up with more information and builds up into a dialogue on each troubleshooting topic. The guide is well written in an easy to understand format and is presented as a pdf where the bookmarks have been carefully set up to allow you to navigate through the document easily and find the topic that relates to your troubleshooting enquiry. Click here to access the guide.
2. Troubleshooting Look-up Table
This is a straightforward troubleshooting resource from Macherey-Nagel where you click on your symptom, be it related to chromatography, pressure or a leak, and the webpage will scroll down and present you with a selection of possible reasons for the problem. I think that it is a good resource to prompt a user who has some experience of HPLC about potential sources of typical problems. There is a little bit of product placement in this tool, where Macherey-Nagel products are recommended, but it's fairly minimal. Click here to access the webpage.
Many manufacturers provide scaling calculators so that you can makes changes to HPLC method parameters and still retain similar chromatography. Recently scaling from HPLC to UHPLC and vice versa has become important as the new capabilities of UHPLC are exploited. One of these calculators is from Supelco, it is available online, and also as mobile app for Android and iPhone/iPad. It’s easy to use, you simply input your current method parameters and the change you wish to make to particle size, column length and internal diameter, the tool will provide the new method conditions. It works for isocratic and gradient methods.
Click here to access the tool.
Liquid Chromatography (Chrom-Ed Series) by Raymond P. W. Scott, Library 4 Science
This useful textbook contains detailed descriptions of the components of liquid chromatography systems, e.g. pumps, detectors, etc., and is likely to be helpful to enhance understanding of these. It also covers silica and bonded phases together with some case studies.
The book is available to purchase on Amazon for only £3.97 but is also available as a free Kindle download on certain days of the month. The next free day is 30th March 2013. Full details are available at: http://www.chromatography-online.org/amazon_free.html
Watch out for the time zone on the download day!
5. USP Column Equivalency Application
For those of you who don’t work in the pharmaceutical Industry, USP is ‘United States Pharmacopeia’. The column comparison tool that they offer is free to access and useful to anyone using HPLC, not just those who work with pharmaceuticals. The tool will allow you to find a column that is equivalent to one which you specify, or may also be used to find a column which has different selectivity, something that can be very useful during method development. Click here to start the application and when you have agreed to the disclaimer, click on ‘Compare Columns’. There are two database options, I recommend the bottom one, or PQRI (Product Quality Research Institute) Database. Select the column you are interested in from the drop down menu and, if you know there are acids and bases in your sample, tick the appropriate boxes. You can also specify a pH. There are two other options, either select ‘View Similar’ or ‘View Different’ as required. A full description of the approach and how the database was created can be accessed on the webpage.
6. LC Calculator from Agilent
This calculator is available as a mobile app for iPhone™ and iPod touch® but there is also a web version that you can use on your desktop (requires flash). It is designed “to help you quickly determine both flow rate and back pressure under a wide variety of conditions and column dimensions”. I think this tool is great for checking out if a method is viable in terms of the back pressure when I want to change method parameters such as particle size, column length and internal diameter, and flow rate. This allows optimisation of the method without having to check these experimentally. Although the system pressure of your HPLC is not included in the result, it still provides a good starting point.
Click here to access the tool, you can select the mobile app or web version. Agilent also provide an article describing the use of the calculator which may be helpful (click here to view).
7. MTS HPLC Calculator