Basic Laboratory Methods for Biotechnology

Textbook and Laboratory Reference

Lisa A. Seidman, Cynthia J. Moore, Jeanette Mowery

• Editore: CRC Press
• Anno: 2021
• ISBN:
  9781000480801
• Edizione: 3
• Argomento: Medizin
• Categoria: Biochemie in der Medizin

Basic Laboratory Methods for Biotechnology, Third Edition is a versatile textbook that provides students with a solid foundation to pursue employment in the biotech industry and can later serve as a practical reference to ensure success at each stage in their career. The authors focus on basic principles and methods while skillfully including recent innovations and industry trends throughout.

Fundamental laboratory skills are emphasized, and boxed content provides step by step laboratory method instructions for ease of reference at any point in the students' progress. Worked through examples and practice problems and solutions assist student comprehension. Coverage includes safety practices and instructions on using common laboratory instruments.

Key Features:

• 
  
  

• Provides a valuable reference for laboratory professionals at all stages of their careers.
  
  

• Focuses on basic principles and methods to provide students with the knowledge needed to begin a career in the Biotechnology industry.

• 
  
  

• Describes fundamental laboratory skills.

• 
  
  

• Includes laboratory scenario-based questions that require students to write or discuss their answers to ensure they have mastered the chapter content.

• 
  
  

• Updates reflect recent innovations and regulatory requirements to ensure students stay up to date.

• 
  
  

• Tables, a detailed glossary, practice problems and solutions, case studies and anecdotes provide students with the tools needed to master the content.

Unit V Obtaining Reproducible Laboratory Measurements

DOI: 10.1201/9780429282799-19

Chapters in This Unit

• Chapter 15: Introduction to Quality Laboratory Measurements
• Chapter 16: Introduction to Instrumental Methods and Electricity
• Chapter 17: The Measurement of Weight
• Chapter 18: The Measurement of Volume
• Chapter 19: The Measurement of Temperature
• Chapter 20: The Measurement of pH, Selected Ions, and Conductivity
• Chapter 21: Measurements Involving Light – Part A: Basic Principles and Instrumentation

Measurements are quantitative observations, or numerical descriptions. Examples of measurements include the weight of an object, the amount of light passing through a solution, and the time required to run a race. Measuring properties of samples is an integral part of everyday work in any biotechnology laboratory or production setting. For example, solutions are required to support the activity of cells, enzymes, and other biological materials. Preparing solutions involves measuring the weights and volumes of the components. Estimating the quantity of DNA in a test tube may involve measuring how much light passes through the solution. The pH of the media in which bacteria grow during fermentation must be monitored continuously. There are countless measurements made in most biotechnology settings, each of which must be a “good” measurement. Obtaining reproducible research results or consistent product quality begins with making “good” measurements.

Case Study: Accurate Measurements Make a Difference

Everyone has experience in making measurements in everyday life. For example, the COVID-19 crisis made everyone more aware of the importance of temperature measurements. In response to the pandemic, many venues instituted a requirement for a temperature check before entering. Any human temperature reading over 100.4° is considered indicative of a fever, according to Centers for Disease Control and Prevention (CDC) guidelines, and therefore a possible sign of illness.

Baking is a familiar area where careful measurements can have a major impact on one’s success. While, unlike in the biotechnology laboratory, many recipes allow a cook to be creative with quantities of ingredients, this is not the case if you want to bake a fluffy, moist cake from scratch. In this case, a key factor is the ratio of flour to liquid and other ingredients. In the United States, home cooks usually measure flour in cups, which is a measure of volume. However, the volume of flour can vary dramatically if it is scooped into a measuring cup from the bag, or sifted and gently sprinkled into the cup. The difference in the actual amount of flour measured as one cup can be as much as 25%! That is more than enough variation to make the difference between a great cake and one that is heavy or dry.

For this reason, experienced cooks and pastry chefs weigh their flour when they bake. No matter how fluffy or packed the flour is, the weight will always correspond to the same amount of flour. If you have a recipe that calls for 270 grams of flour, that is the equivalent of ≈ 2.16 cups of carefully measured flour, an amount that would be difficult for a home cook to recreate accurately. If you have ever read a European cookbook, you will see that the ingredients are weighed out in gram units, rather than measured by volume.

Metric measurements are always used in laboratories to avoid confusion between units of volume and weight. For example, ounces can refer to weight, or to fluid ounces, a measure of volume. For this reason, a good cook would never measure a cup of flour with a liquid measuring cup. Sixteen ounces of flour by weight would measure about twenty-eight fluid ounces in volume. This would not qualify as a good measurement if you use the wrong instrument.

Although it seems obvious that laboratory measurements should be “good,” it is surprisingly difficult to define a “good” measurement. One definition is that a “good” measurement is correct; however, this leads to the question of what is “correct?” Suppose a man weighs himself in the morning on a bathroom scale that reads 165 pounds. Shortly after, he weighs himself at a fitness center where the scale reads 166 pounds. At this point, the man might be somewhat uncertain as to his exact, correct weight; perhaps he weighs 165 pounds, or perhaps 166. Perhaps his weight is somewhere between 166 and 165 pounds. It is also possible that both scales are wrong. He is likely to conclude, however, that he weighs about 165 pounds and leave it at that.

Uncertainty of a pound or so in an adult’s weight is seldom of great concern. A bathroom scale that gives a weight value within 1 pound of the true weight is a reasonably “correct” instrument. In other situations, however, a measurement must be much more correct. For example, a 1-pound difference in the weight of an infant could mean the difference between a healthy baby and one that is severely dehydrated. In the laboratory, an error of 1 g in a measurement could mean the difference between a successful experiment and a disastrous failure. In a drug product, a 1 mg error in measurement could endanger a patient. In each of these situations, a “good” measurement is one that can be trusted when making a decision. A good measurement can be trusted by a physician selecting a treatment for a patient, by a research team drawing conclusions from a study, and by a pharmaceutical company deciding whether to release a drug product to the public.

Laboratory workers play a key role in performing measurements of properties of samples. To make good, trustworthy measurements, laboratory workers must understand the principles of measurement, know how to maintain and operate instruments properly, and be aware of, and avoid, potential pitfalls in measurement. It takes knowledge and careful technique to produce measurements that can be trusted in a particular situation (Figure 1).

Figure 1 Making “good” measurements.

This unit discusses methods of making “good,” trustworthy measurements in the laboratory.

• Chapter 15 introduces basic principles underlying measurements and terminology relating to metrology (the study of measurements).
• Chapter 16 introduces basic principles of electricity and electronics, and instrumental methods of measurement. This chapter serves as a transition to the next five chapters, each of which discusses a specific type of measurement.
• Chapter 17 introduces principles and practices relating to weight measurements in the biotechnology laboratory.
• Chapter 18 introduces principles and practices relating to volume measurements in the biotechnology laboratory.
• Chapter 19 introduces principles and practices relating to temperature measurements in the biotechnology laboratory.
• Chapter 20 introduces principles and practices relating to the measurement of pH, selected ions, and conductivity.
• Chapter 21 introduces principles and practices relating to the measurement of light transmittance and absorbance.

Bibliography for Unit V

Manufacturers are an excellent source of up-to-date information on instrument design, operation, and performance verification. Many manufacturer guides provide clearly written technical information that is not specific to any brand of instrumentation. Checking manufacturer’s websites is often a useful way to get technical information on measurement theory and practice. Some of the manufacturer resources that we find particularly useful are listed below.

NIST publications are an excellent source of information on measurement topic...