Collins Nanotechnology Cookbook

Practical, Reliable and Jargon-free Experimental Procedures
1. Auflage 2012
ISBN: 978-0-08-097173-5
Verlag: Elsevier Science & Techn.
Format: EPUB
Kopierschutz: 6 - ePub Watermark

E-Book, Englisch, 324 Seiten

The peculiarities of materials at the nanoscale demand an interdisciplinary approach which can be difficult for students and researchers who are trained predominantly in a single field. A chemist might not have experience at working with cell cultures or a physicist may have no idea how to make the gold colloid they need for calibrating an atomic force microscope. The interdisciplinary approach of the book will help you to quickly synthesize information from multiple perspectives.Nanoscience research is also characterized by rapid movement within disciplines. The amount of time it takes wading through papers and chasing down academics is frustrating and wasteful and our reviewers seem to suggest this work would give an excellent starting point for their work. The current source of published data is either in journal articles, which requires highly advanced knowledge of background information, or books on the subject, which can skim over the essential details of preparations. Having a cookbook to hand to flick through and from which you may select a preparation acts as a good source of contact both to researchers and those who supervise them alike.This book therefore supports fundamental nanoscience experimentation. It is by intention much more user-friendly than traditional published works, which too-frequently assumes state of the art knowledge. Moreover you can pick up this book and find a synthesis to suit your needs without digging through specialist papers or tracking someone down who eventually may or may not be able to help. Once you have used the recipe the book would then act as a reference guide for how to analyze these materials and what to look out for. - 100+ detailed recipes for synthesis of basic nanostructured materials, enables readers to pick up the book and get started on a preparation immediately - High fidelity images show how preparations should look rather than vague schematics or verbal descriptions - Sequential and user-friendly by design, so the reader won't get lost in overly detailed theory or miss out a step from ignorance - A cookbook, by design and structure the work is easy to use, familiar and compact

Autoren/Hrsg.

Collins, Andrew

Leseproben

Chapter 2
Safety
This is the most important section of the book. Many of the experiments in this book deal with chemical and biological hazards and hazardous reactions. If performed incorrectly or without adequate safety procedures and equipment, there is a real danger that the experimentalist or others around them will be injured or killed. The products of these experiments may be, in and of themselves, toxic and/or hazardous and should be contained or disposed of correctly after use. The above statement may read as sensationalist scaremongering but is absolutely true. Accidents in the laboratory happen all the time (there are weekly bulletins posted by the American Chemical Society’s Chemical and Engineering News). Even when everything appears to be correct with a reaction, there can still be factors beyond your control that result in dangerous problems. The reader should make their safety and the safety of others the main priority when undertaking any work. In this section we will explore some of the considerations surrounding the safety aspect of working with nanomaterials and some of the new protocols to help minimise the potential risks of working with them. Most of this section covers general best practice procedures and the reader should always default to local laboratory practices and regulations. Nanoscopic materials can behave in radically different ways from the bulk counterpart. This means that even materials considered Generally Recognised as Safe (GRAS status) in bulk cannot be considered so after formulation on the nanometre scale. Currently, no separate risk classification exists for nanomaterials and they are treated with the same risk management and disposal procedures that are in place for chemical and biological hazards. The field of nanotoxicology continues to grow and preliminary research shows that nanomaterials do behave in unique ways biologically. This is of some concern as products containing nanomaterials have already been in circulation for some years and the amount produced grows year on year. Some discussion of this is provided at the end of the section. Overall, working with nanomaterials means that you will be responsible for safely producing, handling and disposing of them with control of the associated immediate and long-term risks. This ethos of responsibility is encompassed by the phrase ‘from the cradle, to the grave’. General Laboratory Procedure
All laboratories should have a health and safety framework in place. This includes a hierarchy of people responsible for managing safe laboratory practice and its implementation. People trained as emergency first aiders should be on-site with a contact number on visible display in the laboratory. For every reaction you do, you should perform a risk assessment on it before starting. This is not only a legal requirement in most countries but will also allow you to think out the experiment and spot any potential accidents before they happen. A procedure for this is provided further on in this section. You should be aware of the following in any chemical or biological laboratory: • Fire plan and fire extinguishers. In chemical laboratories, foam or carbon dioxide extinguishers are used. Water extinguishers are normally avoided as some reagents will catch fire on contact with water. • The contact point for first aid and the location of the first aid kit. • The emergency shower and emergency eyewash. • Chemical spill kits. These kits are usually a large bucket of inert adsorbent granules. In the event of a spill, the granules can be used to soak up the liquid and collected to be disposed of. • Reagent lists with the location of the chemicals or general reagent class listed on a map. This makes things easier to find day to day and also helps to keep track of dangerous and hazardous materials. • A secure area for solvent storage (if solvents are used) that is adequately vented. Solvents are normally stored in cabinets built into fume hoods for this purpose. • Solid and solvent waste disposal receptacles or procedures. Private companies will deal with the accumulated waste in the correct way. With the possible exception of washing glassware with water almost everything produced in a laboratory cannot and should not be poured down the sink. • Dedicated glass bins and sharps bins. Both glass and needle waste cannot be mixed with regular waste for any reason. • Never work alone in a laboratory. Some places have out of hours procedures, but these will always rely on having someone in the same room as you to summon aid in case of an accident. • Hands must be washed before leaving the laboratory. Even if you have been wearing gloves. Overall you should never tolerate unsafe practice in a laboratory. This may seem obvious, but it is easy for people to become complacent when they get comfortable with their work. One of the most effective methods of making the laboratory environment less accident-prone is to engender a culture of intolerance to lazy or unsafe practice. From a social point of view, people can sometimes be uncomfortable confronting others about this, but remember, the life you save may be your own. I have heard of a student who was too afraid of confronting a senior researcher about their use of hydrofluoric acid open on the bench instead of a fume hood. The matter was settled by an anonymous note delivered to an even more senior member of staff who then arranged to catch the offender red-handed in a surprise laboratory visit. Even when every safety procedure is followed as carefully as possible, the unexpected can still happen. Below is a photo of a fume cupboard where a reaction under reflux suddenly ‘ran away’. The uncontrolled reaction overpressured the glassware and released that pressure with enough force to shatter the front of the fume hood. In this case no one was hurt but it demonstrates that even with safeguards in place and an approved assessment of the risk, it can all go wrong. After a reaction has been safely conducted, you must still control where your products eventually end up. The photograph in fig. 2.1b shows a bin into which ‘made safe’ chemical waste had been deposited but unexpectedly caught fire overnight. Although independently the waste was benign, a chance combination must have spontaneously ignited. Once more, this type of accident is almost impossible to predict but does help to refine the procedures that will prevent incidents like it from happening again (Fig. 2.1). FIGURE 2.1 (a) A fume hood that has suffered catastrophic damage after a reaction has gone out of control and blown up. (b) The aftermath of a bin fire ignited by incompatible chemical waste. Personal Safety Equipment
There are some items that should be with you at all times when you are in a laboratory. A barrier in some form should be between you and whatever you are working with. Gloves and laboratory coats should remain in laboratory areas and never transferred into offices or group spaces: • Safety spectacles. This is the number one item of equipment to protect you from losing your eyesight. Whenever you are in a laboratory, even if you are not working directly at a bench you should keep safety spectacles on at all times. Explosions in other areas of the laboratory can propel glass and other chemicals at high velocity and spectacles are the only thing that will save your sight. Something nasty could get in your eye at any time. Someone could drop a beaker of acid right next to you and it could splash in your face. You should feel naked without a pair on your face and resist the urge to place them on your head when working close up. Speaking as a former laboratory demonstrator, people will often take them off without thinking. You must notify the owner to immediately put them back on. Confront anyone not wearing safety spectacles in a laboratory and never let someone say ‘it’s OK, I’m not working with anything dangerous’. • A laboratory coat. This is the first defence you have against spills on your clothes and can be quickly removed if it catches fire. Laboratory coats can be washed by specialist companies and should not be washed with normal clothes under any circumstances. • Gloves. There are many different types of disposable gloves and, depending on the chemicals they will be exposed to, not all are suitable for all purposes. You must check that the gloves you are using are compatible with your experiment before starting! Nitrile gloves are commonly used around both chemical and biochemistry laboratories, but it is important to remember that these can be degraded by some chemicals and may offer only a partial barrier to the skin. Latex gloves used to be common but are no longer used as people can become sensitised to using them and they can cause a serious allergic response. A chart grading the protection offered from four common types of gloves against various solvents is provided below (Sourced from Ansell). Risk Assessment
Most reagents and solvents used in a chemistry laboratory are in some way harmful. In a biological laboratory, there is the added risk of being exposed to an infection. A risk assessment must be performed before starting any new experimental procedure and checked with the person responsible for laboratory safety. Every chemical is labelled in some way to denote any potential hazards associated with it. All chemicals will also come with a Materials...