It is now recognised that analytical chemistry must also be a target for green principles, in particular chromatographic methods which typically use relatively large volumes of hazardous organic solvents. More generally, high performance liquid chromatography (HPLC) is employed routinely for quality control of complex mixtures in various industries. Acetonitrile and methanol are the most commonly used organic solvents in HPLC, but they generate an impact on the environment and can have a negative effect on the health of analysts'. Ethanol offers an exciting alternative as a less toxic, biodegradable solvent for HPLC but in order for analysts' to change existing methods, simple strategies for method translation must be demonstrated that offer equivalent analytical performance. In this work we demonstrate that replacement of acetonitrile with ethanol or acetone as the organic modifier for HPLC can be achieved without significantly compromising analytical performance. This general approach is demonstrated through the specific example analysis of a complex plant extract. A benchmark method employing acetonitrile for the analysis of Bidens pilosa extract was statistically optimized using the Green Chromatographic Fingerprinting Response (GCFR) which includes factors relating to separation performance and environmental parameters.  Methods employing ethanol at 30 and 80 �C were developed and compared with the reference method regarding their performance of separation (GCFR) as well as by a new metric, Comprehensive Metric to Compare Liquid Chromatography Methods (CM). The fingerprint with ethanol at 80 �C was similar to or better than that with acetonitrile according to GCFR and CM. Similarly, replacement of acetonitrile with acetone is demonstrated for metabolite profiling of another complex plant extract, obtained from leaves of Lippia alba. In this case charged corona aerosol detection was used, offering both more universal detection that typical UV photodiode array detection and compatibility with acetone as a UV absorbing solvent.

Trade off between separation, detection, and sustainability in liquid chromatographic fingerprinting

248th National Meeting (2014)

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