• Energy Research

High-pressure liquid chromatography (HPLC) is a technique of paramount importance in the analysis of pharmaceuticals because of its ability to separate moderately polar to less polar compounds, such as drugs and related substances.High-pressure liquid chromatography (HPLC) is a technique of paramount importance in the analysis of pharmaceuticals because of its ability to separate moderately polar to less polar compounds, such as drugs and related substances. The concept of green analytical chemistry (GAC) aims to provide more environmentally friendly and safer analytical methods in terms of reagents, energy, and waste. One of the major challenges of GAC is to find an appropriate approach to evaluate the greenness of analytical methods. An extension of GAC, called white analytical chemistry (WAC), has been introduced to consider not only environmental friendliness, but also other aspects that contribute to the sustainability of methods, such as analytical and economic or practical efficiency. HPLC methods are intrinsically not green, due to the high consumption of toxic organic solvents and the resulting generation of large amounts of toxic waste. Fortunately, there are many approaches to overcome the non-green character of HPLC methods. In this article, various modifications of the HPLC methods that increase its environmental friendliness are presented, as well as the various tools used to evaluate environmental friendliness. In addition, the new concept of white analytical chemistry is presented.

High-pressure liquid chromatography (HPLC) is a technique of paramount importance in the analysis of pharmaceuticals because of its ability to separate moderately polar to less polar compounds, such as drugs and related substances.High-pressure liquid chromatography (HPLC) is a technique of paramount importance in the analysis of pharmaceuticals because of its ability to separate moderately polar to less polar compounds, such as drugs and related substances. The concept of green analytical chemistry (GAC) aims to provide more environmentally friendly and safer analytical methods in terms of reagents, energy, and waste. One of the major challenges of GAC is to find an appropriate approach to evaluate the greenness of analytical methods. An extension of GAC, called white analytical chemistry (WAC), has been introduced to consider not only environmental friendliness, but also other aspects that contribute to the sustainability of methods, such as analytical and economic or practical efficiency. HPLC methods are intrinsically not green, due to the high consumption of toxic organic solvents and the resulting generation of large amounts of toxic waste. Fortunately, there are many approaches to overcome the non-green character of HPLC methods. In this article, various modifications of the HPLC methods that increase its environmental friendliness are presented, as well as the various tools used to evaluate environmental friendliness. In addition, the new concept of white analytical chemistry is presented.

Abstract Green analytical chemistry is primarily directed towards minimization of the amount of waste associated with either the sample preparation or analysis. Among different chromatographic methods, liquid chromatography is considered the least green, allowing for various possibilities for greening. Using green solvents such as ethanol or acetone in RP-HPLC, as an alternative to acetonitrile, is recently attracting an attention. Both ethanol and acetone are characterized with low toxicity, with certain drawbacks limiting their regular use in RP-HPLC. Ethanol has low eluotropic strength and causes high backpressures, while acetone shows high UV cut-off, making it unsuitable for UV/Vis detection. To overcome the existing problems, Corona Charged Aerosol Detector was employed for development of RP-HPLC methods for separation of risperidone and its structurally related impurities with either ethanol or acetone as organic modifier. The methods were optimized by experimental design methodology, while optimal conditions for separation were determined using Derringer's desirability function. Detailed assessment of 3D surface plots of Derringer's desirability function enabled selection of 0.6 mL min−1 flow rate and 20% (v/v) organic modifier content as optimal when using ethanol, while in case of acetone mobile phase flow rate was 0.8 mL min−1 and organic modifier content 17% (v/v). Methods were validated and their eco-friendly character was confirmed through Green Analytical Procedure Index (GAPI). Although both methods are ecologically acceptable, the main drawback is reflected in the fact that no recycling or another waste treatment method exist. In the end, acetone was prioritized over ethanol, due to lower health hazard and decreased amount of generated waste.

Abstract Green analytical chemistry is primarily directed towards minimization of the amount of waste associated with either the sample preparation or analysis. Among different chromatographic methods, liquid chromatography is considered the least green, allowing for various possibilities for greening. Using green solvents such as ethanol or acetone in RP-HPLC, as an alternative to acetonitrile, is recently attracting an attention. Both ethanol and acetone are characterized with low toxicity, with certain drawbacks limiting their regular use in RP-HPLC. Ethanol has low eluotropic strength and causes high backpressures, while acetone shows high UV cut-off, making it unsuitable for UV/Vis detection. To overcome the existing problems, Corona Charged Aerosol Detector was employed for development of RP-HPLC methods for separation of risperidone and its structurally related impurities with either ethanol or acetone as organic modifier. The methods were optimized by experimental design methodology, while optimal conditions for separation were determined using Derringer's desirability function. Detailed assessment of 3D surface plots of Derringer's desirability function enabled selection of 0.6 mL min−1 flow rate and 20% (v/v) organic modifier content as optimal when using ethanol, while in case of acetone mobile phase flow rate was 0.8 mL min−1 and organic modifier content 17% (v/v). Methods were validated and their eco-friendly character was confirmed through Green Analytical Procedure Index (GAPI). Although both methods are ecologically acceptable, the main drawback is reflected in the fact that no recycling or another waste treatment method exist. In the end, acetone was prioritized over ethanol, due to lower health hazard and decreased amount of generated waste.