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The CHROMacademy Essential Guide Webcast:
Troubleshooting Sample Preparation

Thursday 14th June 2018,
8:00am PDT/ 11:00am EDT/ 4:00pm BST/ 5:00pm CEST


This webcast will address some of the most common problems encountered in the lab when carrying out sample preparation using filtration, liquid-liquid extraction (LLE), and solid phase extraction (SPE).  We will provide troubleshooting strategies as well as tips and tricks to avoid problems in the first place.

Presented by

Dr. Doug Raynie (Associate Research Professor, Department of Chemistry and Biochemistry, South Dakota State University)
Dr. Dawn Watson (CHROMacademy Technical Expert, Crawford Scientific)

Topics Covered

Essential sample preparation troubleshooting strategies

  • Filtration
    • Selecting the correct filter membrane
    • Avoiding unwanted analyte/membrane interactions
    • Matching filter dimensions to sample volume
  • Liquid-liquid extraction (LLE)
    • Improving quantitation
    • Treating emulsions
    • Acid/base/neutral extractions - where’s the analyte?
  • Solid phase extraction (SPE)
    • Dealing with the most common SPE problems
      • Recovery
      • Reproducibility
      • Cleanliness

Presenter Information »


Troubleshooting Sample Preparation

This month’s webcast took a closer look at troubleshooting some of the most common sample preparation techniques – filtration, liquid-liquid extraction, and solid phase extraction.  The CHROMacademy material provided in this month’s tutorial will provide you with further knowledge on the science behind these techniques which will allow you to make the correct decisions during method development to hopefully avoid many of the common pitfalls.

Our Quick guides, CHROMacademy course content, and archived webcasts and tutorials will provide you with the knowledge required to become a troubleshooting expert.

Watch the webcast
eLearning Modules

Primary Sample Preparation Techniques

This module introduces a variety of sample preparation techniques including, filtration, protein precipitation, liquid-liquid extraction, and solid phase extraction.

Sample Filtration and Ultrafiltration | The Partition Coefficient
Liquid / liquid Extraction | Solid Phase Extraction


Liquid-Liquid Extraction Techniques

Understand how liquid-liquid extraction works and any pitfalls you may encounter.

Drawbacks of Liquid/liquid Extraction | Emulsions
Support-Assisted Liquid / liquid Extraction II


Quick Guides

Investigating SPE Recovery Problems

One of the most common problems in SPE is poor or inconsistent recovery.  This quick guide details how to determine if you have a recovery problem and defines step by step procedures which can be used to assess at which point in the SPE process loss of analyte(s) is occurring.

Investigating SPE Recovery Problems »


Troubleshooting SPE Reproducibility Problems

The most common causes of reproducibility problems in SPE are a non-rugged method, protein binding problems, or changes to the sorbent from the manufacturer. This quick guide will lookat how to assess, troubleshoot, and remedy this problem.

Troubleshooting SPE Reproducibility Problems »


Troubleshooting SPE Cleanlinesss

Another common problem we see with SPE is poor cleanliness.  This problem can be remedied by altering wash and elution solvents or assessing alternative extraction mechanisms.

Troubleshooting SPE Cleanliness »


Troubleshooting Filtration

The first step to troubleshooting (or avoiding having to troubleshoot) any sample preparation or analytical method is to select the correct method and equipment in the first place.  However, this does not guarantee that problems may not arise.  The following article will look at selecting the correct syringe filter, where to find relevant information on selecting a syringe filter, and what common problems may arise during filtration using syringe filters.

Troubleshooting Filtration »


Troubleshooting Liquid-Liquid Extraction

Liquid-liquid extraction (LLE) is the most widely used extraction technique for liquid samples.  The information provided in this article will mainly focus on liquid-liquid extraction (LLE) using a separatory funnel, however, many of the principles are applicable to the more modern miniaturized approaches to LLE i.e. single drop microextraction (SDME), flow-injection extraction (FIE), membrane extraction techniques, and supported liquid extraction (SLE).

Troubleshooting Liquid-Liquid Extraction »


Top Tips to Improve Reproducibility and Sensitivity in Solid Phase Extraction

A robust and sensitive method is the product of meticulous method development. In this webcast we will consider the most pertinent steps in SPE method development and how the decisions which are made can impact on reproducibility and sensitivity.

Improve Reproducibility and Sensitivity in Solid Phase Extraction »


Choosing the Correct Sample Preparation Technique

“Before anything else, preparation is the key to success” Alexander Graham Bell.

This is certainly true in analytical chemistry. The correct choice of sample preparation method for a sample prior to analysis can have a myriad of benefits; properly prepared samples will produce simpler chromatograms free from interfering peaks, instrument parts will be protected from harmful contaminants which could result in break downs and the need for increased maintenance, and the sample will be compatible with the analysis method (correct pH, solvent etc.) minimizing deleterious chromatographic effects. This Essential Guide webcast will provide details of sample preparation techniques and guide you to the correct method for your sample; whether it is a simple liquid/liquid extraction or a more complex solid phase extraction.

Choosing the Correct Sample Preparation Technique »

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Dr. Doug Raynie
Associate Research Professor, Department of Chemistry and Biochemistry,
South Dakota State University

Dr. Doug Raynie is an Associate Research Professor in the Department of Chemistry and Biochemistry at South Dakota State University.  Prior to joining SDSU, he was employed for eleven years as a Senior Scientist at Procter and Gamble's Corporate Research Division. 

He earned his Ph.D. at Brigham Young University under the direction of Dr. Milton L. Lee.  His undergraduate degree is from Augustana (South Dakota) College, with majors in chemistry and biology.
Dr. Raynie’s broad research interests are in the field of sustainability and green chemistry.  His two major areas of research are bioprocessing using supercritical fluids and related technologies and analytical separations.  Active projects in this area include transformations of lignocellulosic biomass using supercritical fluids and ionic liquids.  Analytical separations research includes utilization of deep eutectic solvents, high-resolution chromatography (high-temperature LC and SFC), chromatographic sample preparation (ASE, SFE, SPME, and SPE), chromatography theory, green analytical chemistry, and problem-based learning in analytical chemistry.

Dr. Raynie serves on the editorial advisory boards of the Encyclopedia of Separation Science and Pharmaceutical Formulation and Quality

Dr. Dawn Watson CHROMacademy Technical Expert
Crawford Scientific

Dawn, completed her PhD in synthetic inorganic chemistry at the University of Strathclyde, Glasgow, followed by postdoctoral research on small molecule reaction kinetics at Princeton University.

Following several years working for a major instrument manufacturer, she became a technical expert for CHROMacademy in 2013.

She has expertise in various analytical techniques, including HPLC, GC, GC–MS, LC–MS, NMR, and molecular spectroscopy.