MSACL 2017 US Abstract

Use of Automation to Achieve High Performance Solid Phase Extraction

Mark Hayward (Presenter)
ITSP solutions

Bio: PhD Purdue: Mass Spectrometry - Prof. Cooks group, 22 yr career in Pharmaceutical companies (Wyeth, Novartis, Lundbeck), Currently Chief Scientific Officer at ITSP Solutions, Recognized expertise: chemistry, separations, mass spectrometry, biomarkers, method development, robotics, informatics, molecular biology, solving complex molecular problems at the molecular level, and building clinical laboratories

Authorship: Mark Hayward,1 Jonathan Ho,2 Matthew T. Hardison,3 Martin Johnson,3 Tom Moran,2 and Kim Gamble1
1ITSP Solutions Inc., 10 South Carolina St., Hartwell GA 30643 2Shimadzu Scientific Instruments, 19 Schoolhouse Rd, Suite 107, Somerset NJ 08873 3Assurance Scientific Laboratories, 2868 Acton Rd, Suite 207, Vestavia, AL 35243

Short Abstract

Despite >40 yr of SPE using LC sorbents, LC principles have been ignored due to the lack of flow control in SPE devices. Variable flow results in variation in results. Internal standards are used to achieve meaningful results. Measuring absolute recovery against external standards to demonstrate absence of matrix effect (gold standard) isn’t done. With a new SPE device, this is changed. It uses a syringe to achieve both automation & accurate flow. With PAL autosamplers, SPE & LC/MS/MS is automated in a single parallel workflow. van Deemter curves are measured & SPE performed at flow achieving >99% absolute recovery. As a micro device, sample dry down isn’t needed for enrichment up to 200x. SPE is performed efficiently, economically, & with performance matching all LC knowledge of the last 50 yr. Examples of clinical measurement using reverse phase & ion exchange SPE are provided.

Long Abstract

Despite >40 yr of SPE using LC sorbents, LC principles have been ignored. At the root of this is the lack of flow control in the SPE devices in use today. Whether using vacuum or pneumatic pressure, the changing volume of liquid above the sorbent changes the flow rate through the sorbent. When SPE is performed in parallel, this effect is exacerbated because each SPE device (or well) has a different resistance to flow. The result of all the variable flow is considerable variation in results. Internal standards must be used to achieve meaningful results with all single use SPE devices and overall data must be judged based on the worst case scenario (flow far from optimal). Furthermore, achieving >99% absolute recovery against external standards, the gold standard in demonstrating the absence of matrix effects, seems to be lost.

With the invention of the ITSP SPE device, all of the above is changed. The ITSP SPE cartridge is designed around the syringe in order to achieve both automation (SPE cartridge transport) and accurate flow (performance like LC columns). The result of its use with a CTC/PAL autosampler is total automation of SPE and LC/MS/MS (or GC/MS/MS) measurement in a single parallel workflow (SPE & LC/MS/MS in parallel). SPE method development is a matter of systematically applying chromatographic principles. van Deemter curves can be measured for SPE cartridges (proving reversible adsorption/desorption equilibria) and SPE can be performed at the optimal flow rates to achieve >99% absolute recovery versus external standards. In addition, accurate flow benefits targeted matrix removal allowing >99% removal in wash steps where the optimal flow is not necessarily the same as load and elute steps. Furthermore, SPE sorbent particle size can be reduced to increase SPE speed (where needed for large sample volumes). Since this SPE cartridge is a micro SPE device, sample dry down is no longer needed to achieve sample enrichment as high as 200x. Finally, SPE can be performed with single use devices efficiently, economically, and with a performance level that matches all chromatographic knowledge gained in the last 50 years. Compelling examples of clinical measurements using reverse phase and ion exchange SPE will be provided.


References & Acknowledgements:

J.J. van Deemter , F.J. Zuiderweg, A. Klinkenberg, Chem. Eng. Sc., 1956, 5, 271–289. [quantitatively established the importance of flow in chromatography and linked this to each of the physico-chemical processes]

Neue, UD, HPLC Columns: Theory, Technology, and Practice, Wiley, 1997, p77. [shows gradient liquid chromatography follows the same fundamental principals as isocratic chromatography (basis of all theory)]

Giddings, JC, Unified Separation Science, Wiley 1991, p 92-101. [total coverage of all fundamental chromatographic principles]


Financial Disclosure

DescriptionY/NSource
Grantsno
SalaryyesITSP Solutions
Board Memberno
Stockno
ExpensesyesITSP Solutions

IP Royalty: no

Planning to mention or discuss specific products or technology of the company(ies) listed above:

yes