Practical Instrumental Analysis

Methods, Quality Assurance, and Laboratory Management

Sergio Petrozzi

• Publisher: Wiley-VCH
• Year: 2012
• ISBN:
  9783527665914
• Edition: 1
• Topic: Ciencias físicas
• Subtopic: Química analítica

This practical book in instrumental analytics conveys an overview of important methods of analysis and enables the reader to realistically learn the (principally technology-independent) working techniques the analytical chemist uses to develop methods and conduct validation. What is to be conveyed to the student is the fact that analysts in their capacity as problem-solvers perform services for certain groups of customers, i.e., the solution to the problem should in any case be processed in such a way as to be "fit for purpose".
The book presents sixteen experiments in analytical chemistry laboratory courses. They consist of the classical curriculum used at universities and universities of applied sciences with chromatographic procedures, atom spectrometric methods, sensors and special methods (e.g. field flow fractionation, flow injection analysis and N-determination according to Kjeldahl).
The carefully chosen combination of theoretical description of the methods of analysis and the detailed instructions given are what characterizes this book. The instructions to the experiments are so detailed that the measurements can, for the most part, be taken without the help of additional literature.
The book is complemented with tips for effective literature and database research on the topics of organization and the practical workflow of experiments in analytical laboratory, on the topic of the use of laboratory logs as well as on writing technical reports and grading them (Evaluation Guidelines for Laboratory Experiments).
A small introduction to Quality Management, a brief glance at the history of analytical chemistry as well as a detailed appendix on the topic of safety in analytical laboratories and a short introduction to the new system of grading and marking chemicals using the "Globally Harmonized System of Classification and Labelling of Chemicals (GHS)", round off this book.
This book is therefore an indispensable workbook for students, internship assistants and lecturers (in the area of chemistry, biotechnology, food technology and environmental technology) in the basic training program of analytics at universities and universities of applied sciences.

1

Introduction

1.1 Analytical Chemistry – The History

Already in ancient Egypt, knowledge of chemistry existed and was used when embalming pharaohs and dignitaries. Greek philosophers such as Plato (428–347 BC), Aristotle (384–322 BC) or Empedocles began to look for rules to explain natural phenomena. Plato believed that diverse atoms could be differentiated by their constitution. According to this theory, the atoms of an element could be changed into those of another element by simply modifying the form. Aristotle postulated that all elements and the substances formed by them were composed of a kind of original substance. This original substance, however, could, in the course of time, take on many forms, such as shape and color. Empedocles, who lived sometime between 490 and 430 B.C., explained that all substances were composed of four elements, namely fire, earth, water and air.

Ever since the beginning of alchemy in the Middle Ages, men have sought for a material with which to best convert metal fastest and most simply and that could be exploited best. That was the stone of wisdom. The ability to illustrate this was generally regarded as an Act of God’s mercy, even if someone owned a functioning specification, it would have been useless without God’s intervention. The Phlogiston Theory was introduced by the German physician and chemist Georg Ernst Stahl (1659–1734) in 1697. According to this theory, all flammable substances contained Phlogiston (gr. phlox, the flame). When it was burned and/or oxidized the flame escaped as a gas-shaped something. Phlogiston was a hypothetical substance that could be used without having necessarily to be proven. This assertion was applied to all appearances of fire in nature and ruled the thoughts of chemists for almost one hundred years. A substance would burn more readily, the more Phlogiston it had.

The spiritual aspect went hand in hand with the scientific aspect. Aristotle added a fifth, supernatural element to these four. The quintessence as the most inner core of all substances and to which a sustaining and healing power was attributable. Quintessences were gained by extraction, that is, by separating all ineffective or unpurified ingredient. These were material essences which were the sum of a body’s own effective powers and/or qualities. The idea of a microcosm and a macrocosm stated that everything that occurred in the universe (macrocosm) had its correspondence and effect on earth (microcosm). As early as in Babylonian astronomy the planets were linked to certain materials (e.g., moon – silver, sun – gold). The constellation of the planets was important for chemical reactions to be successful.

The Renaissance witnessed the birth of attempts to renew chemistry. People wanted to get rid of everything, one by one, which was not rationally explicable. The making of gold and the associated magic, astrology and magic methods could not be reconciled with chemistry which was grounded in insights and based on reason. More and more chemists turned their backs on alchemy and finally began to fight against it. The chemists upheld research and the critical ability to think, reason, as the highest judge of the truth of a theory. In parallel to chemistry, analytical chemistry developed its own experimental skills. The first quantitative determination in chemistry was conducted by A.L. Lavoisier (1743–1794) and as early as the nineteenth century, analytical chemistry had become an established branch of chemistry. In a book published in 1894, W. Ostwald described “The Scientific Foundations of Analytical Chemistry”. In this book he introduced dissociation constants, solubility products, ion products, water ion products and indicator equilibrium into analytical chemistry.

Analytics today determines the success of science, technology and medicine and is an interdisciplinary field. At the beginning of this development, analytical investigations were limited to the composition of substances and/or of mixed substances with regard to their main components. At the same time the need for generalization of analytical methods, not only on the basis of the theory of chemical reactions, but also on the basis of the physical theory of the structure of atoms and molecules arose. Later, procedures were developed to analyze trace amounts of an element or a chemical compound in a mixture. Determination of the structure of molecules and investigation of the structure of solids also became important fields for the analyst.

1.2 Analytical Chemistry and Its Role in Today’s Society

Analytics is an interdisciplinary, scientific discipline also termed “analytical chemistry”. The terms quantity and quality owe their existence to the results of analytics. Analytical issues are all-pervasive, and by no means only a part of scientific discipline. Rather, analytics often has a predominant role in the industrial value chain. Increasingly, more quality characteristics are being allotted to products and processes, which increasingly correspond to the need for analytics in all areas of life. Our society is demanding analytically secured data and judgments instead of empirical or traditional foundations for general or industrial decision-making. In this manner medical diagnostics, for example, is being shaped more and more by methods of analytical and bioanalytical chemistry. Buzzwords such as food security or water contamination, greenhouse gases or doping tests, gene analysis or certification of genuineness are visibly tied to the performance of analytical chemistry, visible for every citizen. Good analytics create trust and thus are a pre-requisite for production and marketing.

Responsible political and economic decisions have long been based on ecological insights, that is, findings based on environmental analytics. The concept of sustainability will be even more important in future, and this draws on analytical competence even more than any concept of human action has ever done. In a nutshell: More and more ideological, medical, legal and economic decision-making rests on analytical data. This applies both to the governmental control of such areas as health, the environment, security and resources, and to the control of trade and economic processes. Similarly, the decisive spurt in the development of high technology (microchips, high-tensile materials, medical diagnostics) is always based on highly developed analytics. Increasing globalization and the progressive growing together of the countries of Europe have reduced trade barriers at their borders. The goal is to facilitate a free and unprohibited exchange of products and services. With this development, it is becoming more necessary than ever, however, to make the quality of goods transparent, because only supplementary information on the composition, purity or reliability of goods makes them salable commodities.

In order to guarantee uniform procedures across national borders when collecting analytical information, international guidelines, such as Good Laboratory Practices (GLP), Good Manufacturing Practices (GMP) or standards for good analytical work (e.g., International Organization of Standardization – ISO 17025) have been introduced.

These aspects make it clear that analytics is of fundamental significance and that this trend will continue. Analytics is the common task of several partners including universities, industry, analytics laboratories, the equipment industry and the authorities. Thus Europe will in future increasingly need the respective analysts, laboratories, educational and research institutions, more than ever before.

Only 40% of German universities have specialist analytical departments in the faculty of chemistry. This is the result of a study by the Society of German Chemists (SGCh). In some 50% of these it is tied to the subject “inorganic chemistry” since, traditionally, beginners in chemistry were introduced to the subject by way of simple analytical laboratory tasks. A cross-discipline like analytical chemistry, with increasing research roles in the whole area of material sciences, food science and medicine suffers from such a wrong allotment or subordination.

The concept of sustainability, which also takes a central position in the code of conduct of the GDCh (https://www.gdch.de/home.html, accessed May 2012), requires an extended concept of education: Beyond the difficult issue of the sciences the education must take into consideration the consequences of insights and their material implementation. Herein lies one of the most demanding tasks of the universities that have to convey high chemical analytical understanding. The specialist areas/faculties of chemistry and the university management are called upon to reinforce analytical chemistry in the further and new development of the curricula and to ensure and make use of their interdisciplinary function. Research promotion should clearly set priorities. Chemical analytical research is dependent on taking a leading position in methodology development and in giving preference to the application of expressly demanding issues. Only a quality-oriented promotion of research in stable interdisciplinary research structures of analytics can create the prerequisites that pave the way for industry (equipment manufacturers and users) in increasingly more areas to successfully offer automated or reliable practicable methods, and to market and use these globally.

It is therefore in the long-term interest of universities, politicians and the economy to firmly establish strong structures of education and research in analytical chemistry.

Excerpt from: Society of German Chemists (GDCh) – Memorandum Analytics 2003.
The Gesellschaft Deutscher Chemiker (GDCh) is the largest chemical society in continental Europe with members from academe, education, industry and other areas. The GDCh supports chemistry in teaching, research and application and promotes the understanding of chemistry in the public.
I’m not afraid of storms, for I’m learning to sail my ship.

Aeschylus

2

Introduction to Quality Management

Quality. There is hardly another term mentioned more often in connection with products and services. Entire branches thrive from “selling” quality or from supporting corporations in their quality efforts. However, what is actually the essence of quality? Where does quality come from and how has the term changed over the centuries?

General definition:

Quality is understood to be synonymous with high value. It is not measurable, but rather it can merely be grasped (subjective term) by experience. Unsuited to corporate practice.

Product-related definition:

Quality is interpreted as being measurable. It becomes an objective characteristic, whereby subjective criteria are eliminated. (Example: The larger the cucumbers the more valuable, the better the quality)

User-oriented definition:

Quality only exists from the point of view of the user, that is, the customer.

Process-related definition:

Quality is equated with compliance with specifications. There exists a zero-defect policy (do it right the first time). (Example: Punctuality of a means of transport, a zero-defect product)

Value-related definition:

Taking into consideration the cost and/or price of a service, quality means a favorable price/performance ratio.

The consequence for corporate practice is that the various functional areas in a corporation develop varying opinions of just what quality is.

2.1 Historical Background

The pre-industrial technical production (as opposed to agrarian production) was handicraft production, whereby the so-called system of guilds played a decisive role from an organizational standpoint. The guilds determined the manufacturing procedures, tool types, tool use and even production quantities. On the one hand, they gave the craftsman social stability and ensured his company. On the other hand, their rigidity impeded innovation, technical progress and the expansion of production.

The link between the production of the craftsman according to the guild system and modern industrial production according to the factory system was the already more strongly centralized manufacturing system. They then continued to process the raw material on their own, or under their own control in centralized production sites.

With the industrial revolution in Great Britain, that reached its zenith between 1780 and 1820, technology changed drastically, as new machines were provided (for example, Watt’s steam engine).

The transition of the production method from individual producers to the factory first took place in the English wool-producing textile industry from about 1800 to 1820. Technically the era was characterized by the rapid transition from hydroelectricity to the steam engine, as the driving force for the new textile machines which led the mechanization process. What was also characteristic was the system by which work was divided, that is, the division of production into individual work steps and the distribution to hundreds and thousands of workers. Industrial work was now finally concentrated in one place, the factory and synchronized with the running machines. The economic consequences of the factory system were mass production, the fall in the price of industrial products and a distribution and marketing system that catered to mass-produced products.

The corresponding development and spread of precision tool machines, as existed in the USA, were indispensable prerequisites. In the 1890s the automation of work processes already existed with the use of these machines.

What was also of great significance was the rationalization of the workflow under the influence of the concept of scientific management developed in 1895 by the American production engineer Frederick Winslow Taylor (http://www.skymark.com/resources/leaders/taylor.asp, accessed May 2012).

This involved, for example, breaking down the production process into calculable elements and recording and eliminating redundant movements and hidden breaks.

Mass production of goods also induced a different understanding of quality. It was largely unclear why products did not have the required quality, although their production required only a few twists. The production processes were not predictable and people worked feverishly to control them. Walter Shewhart played a key role here (http://www.skymark.com/resources/leaders/shewart.asp, accessed May 2012).

2.2 Variability

All systems and processes demonstrate a certain variability. This variability is typical of each process. No two things are exactly identical. Even if they appear to be identical at a first glance, they turn out to have differences upon closer inspection that had been hidden from the observer. When we become interested in quality, we must understand where this variability comes from and how it influences the process or the work results, respectively. Shewhart, one of the early pioneers of quality management, divides variability into two categories according to its origin:

• systematic influences (common causes), and
• random influences (special causes)

For exa...

Table of contents

• Cover
• Related Titles
• Title page
• Copyright page
• Preface to the German Edition
• Preface to the English Edition
• Dedication
• Foreword
• 1 Introduction
• 2 Introduction to Quality Management
• 3 Fundamentals of Statistics
• 4 The Analytical Process
• 5 Example of a Validation Strategy
• 6 Organizational and Practical Procedures in the Teaching Laboratory Program
• 7 Literature
• 8 Projects
• Appendix A Selection of Recommended Sources by Subject Area
• Appendix B Statistical Tables
• Appendix C Obligatory Declaration for Students
• Appendix D The International System of Units (SI) – and the “New SI”
• Appendix E Evaluation Guide for Formal Reports
• Appendix F Safety in the Analytical Laboratory
• Index