Chemistry Reference
In-Depth Information
the use of Near-IR spectroscopy as an universal method suitable for the identification of raw materials in the
pharmaceutical industry [11, 12, 13]. Faced with the problems of maintaining regulatory compliance with an
increasing amount of raw material analysis, many pharmaceutical companies focused on Near-IR spectroscopy
to save time and cost, and increase productivity in preference to of the most commonly employed methods in
the past based on chromatography.
Early versions of Pharmacopoeia methods specified a number of different analytical methods for testing
individual raw materials including UV-Visible (UV-Vis) spectroscopy and Gas Chromatography (GC).
However, the aforementioned methodologies frequently involve the use of organic solvents to dissolve the
sample or to leachate the analytes before to perform their determination, reducing the sample analysis
frequency, increasing the costs of analysis and creating toxic wastes and environmental side effects.
Moreover, Near-IR spectroscopy is used in the food industry for the prediction of a wide range of specific
chemical and physical properties such as water, protein, starch and grain hardness among others [14]. Due to
its intrinsic properties, Near-IR is really useful to the brewery industry [15], oil mills [16], feed production
industry [17] and dairy products [18] as a quality assurance tool for raw materials.
The most important advantages offered by Near-IR spectroscopy in the quality control of raw material, which
can be extrapolated to the mid-IR range, are those related to: (1) reduction of the analysis time, (2) elimination
of the consumption and concomitant disposal of solvents used in sample preparation and (3) elimination of
worker exposure to noxious solvents used in the wet chemistry and toxic components of raw materials.
Concerning the elemental composition of raw material, especially in metallurgical, ceramic and concrete
production, the use of X-ray fluorescence as screening technique, together with that of IR spectroscopy
permits a fast identification and semiquantitative determination of the elements present in the raw products
by their secondary X-ray emission [19] and a correct identification of structures from their specific links
clearly identified by the IR [20] and also by the Raman spectra [21].
In short, the advantage of the aforementioned green analytical tools for raw material fast characterization
is the possibility to obtain a complete picture of material composition without any previous chemical treatment
directly from the samples. So, from both the environmental and the industrial points of view it is clear that a
fast characterization of raw materials provides an important tool for preventing manufacturing problems and
contributes to assure the quality of the final products.
On the other hand, quality control is traditionally the most important task assigned to the industrial laboratories
and to do it, the laboratories must be equipped with tools for both the testing of the physical and practical
properties of finished products and as well as their chemical composition and here, once again, greening the
laboratory practices has the double interest of avoiding environmentally deleterious side effects of the use of
toxic reagents, reducing the cost of the quality control analysis and increasing laboratory productivity.
The use of liquid chromatography (LC) as analytical method for the quality control of finished products is
widely extended, being the reduction of the volume and toxicity of the employed reagents and generated
wastes one of the key points of Green Analytical Chemistry.
Pfizer is one of the pioneering companies who are worried about climate change and in 1996, started a
research program named
Pfizer's Energy and Climate Change Program
[22] to focus on greener synthesis
processes and analytical methods for the quality control of raw materials and finished products. The main
goal of the Pfizer's project was to green its processes to help the environment, saving production costs at the
same time. For instance, the company is promoting ethanol based HPLC methods to replace acetonitrile as a
mobile phase. Acetonitrile is considered as an EPA Hazard Air Pollutant and diverse sources affirm that NO
2
,
linked to acid rain, is a byproduct of its incineration process. In this sense, pharmaceutical companies using
acetonitrile in their compliance with good manufacture practices (CGMP) validate HPLC methods which aim
to modify their procedures to remove or reduce the acetonitrile use. Unfortunately, acetonitrile has been
traditionally considered the best solvent in reverse-phase (RP) HPLC due to its physical and chemical
properties and its UV absorbance characteristics. However, recently, more and more specialized voices claim
