A comprehensive course in the systematic development of liquid chromatography separations using QbD principles. In this section, we start with an intuitive approach to show how your inherent understanding of isocratic separation can be translated to gradients. We develop a simple model of gradient elution that enables us to use the same strategy for method development that we used with isocratic methods.
This course is designed for practical workers in the laboratory who have the responsibility for designing new HPLC or UHPLC methods or transferring methods between laboratories. Experienced workers will get the most out of this class, but because it builds from the fundamentals, anyone with experience in HPLC or UHPLC will gain valuable knowledge.
This course covers:
In this section, we start with an intuitive approach to show how your inherent understanding of isocratic separation can be translated to gradients. We develop a simple model of gradient elution that enables us to use the same strategy for method development that we used with isocratic methods. Gradients have a reputation for problems, so we spend time looking at things that can go wrong and how to avoid them or correct the problems if they do occur. Starting with a “universal” scouting gradient can be the fastest way to develop a separation – either isocratic or gradient – and with the help of a spreadsheet calculator, you can use this scouting gradient to quickly move to near-optimum isocratic or gradient conditions.
- How Gradients Work
- Controlling the Separation (in two parts)
- Potential Complications
- The Power of the Scouting Gradient
- Even More Power
By attending this online training course you get full access to the 38 video modules and approximately 12.5 hours of instruction. You also get handouts containing copies of all of the approximately 520 PowerPoint slides used in the class. These are arranged for easy note-taking while you view each module and give you a valuable resource for future reference.
This module has a complementary quiz. By correctly answering the quiz questions for all of the modules as part of the course you will be able to download your certificate of completion. Types of questions to expect are:
- Why are gradients recommended when isocratic retention exceeds a k-range of about 1-20?
- What is true about gradients?
- How is the 25%/40% rule is applied to a scouting run?
- What is a valid description of gradient elution?
- What is true for gradient elution?
- What happens when the gradient slope is changed?
- What happens when the initial gradient conditions are modified and the gradient slope is kept constant?
- What happens when the final gradient conditions are modified and the gradient slope is kept constant?
- What is the effect of changing the flow rate for a gradient?
- Which is true about changes in gradient shape?
- What is true about steep or stepped gradients?
- What advice is correct for segmented gradients?
- What is the dwell volume (delay volume)?
- How do we describe the dwell volume?
- How do we measure dwell volume?
- What is “ghost” peaks (those that appear in a blank gradient)?
- What is true about a scouting gradient?
- When picking scouting gradient conditions, what factors should be considered?
- What things are true about using a scouting gradient?
- Why is it a good idea to make two gradient scouting runs with different slopes?
- When two initial gradients with MeOH as the B-solvent are not successful, what step should be taken next?
- Why is it often useful to run two gradients at two temperatures (4 runs total) during method development?
Analytical Training Solutions, brought to you by Separation Science, is the leading global portal for fundamentals, best practice, troubleshooting and method development training for chromatographic and mass spectrometric techniques. Comprehensive, self-paced online courses and validated learning provides a unique education resource for analytical chemists. Currently, we offer HPLC training, LC-MS training, GC training and GC-MS training.