The Goal Of This Lab Is To Become More Familiar With Understanding Material Safety Data Sheets (MSDS) And To Introduce You To Some Common Reference Sources

CHEM 121 – NSCC Instructor: Maxi Boeckl Fall 2010

Material Safety Data Sheet (MSDS) of Common Chemicals

The goal of this lab is to become more familiar with understanding Material Safety Data Sheets (MSDS) and to introduce you to some common reference sources.

Material Safety Data Sheets (MSDS) The Washington Legislature passed the Worker Right to Know Law in 1984, also known as the Chemical Hazard Communication Standard. This law gives employees the right to know about hazardous chemicals used in the work place. In addition, manufacturers of hazardous chemicals must supply information about the nature and dangers of these materials to their customers. This information is provided in the form of MSDS’s. Employers must maintain a MSDS for each hazardous material they have at their facility.

The following 13 sections are required by law on each MSDS: 1. The name of the chemical product. 2. The manufacturer and a phone number for hazard and emergency information. 3. The date the MSDS was prepared. 4. The chemical name(s) of all hazardous ingredients. 5. The amount of chemical to which you may safely be exposed. 6. The physical and chemical properties of the product. 7. The physical hazards of the product (flammable, corrosive, irritant…). 8. How the chemical might enter the body. 9. The health hazards of the material and how to detect if you have been exposed to the chemical at a dangerous level. 10. Carcinogenic compounds contained in the product must be listed. 11. Emergency and first aid procedures. 12. Safety precautions to take when using the material. 13. Exposure controls (how can you minimize your exposure when using the product).

Today MSDS’s can be easily found on the internet. There are several options. Whichever way you find the MSDS, make sure you are looking up the MSDS for the correct compound and not for a derivative (for example, thiamine not thiamine hydrochloride). MSDS will vary greatly in length and comprehensiveness. So it might be a good idea to check out at least two different sources. 1. www.MSDSonline.com allows you to access a limited amount of MSDS’s for free. This site is one of the most comprehensive sites, but it requires you to register (also free). 2. Chemical distributors are a great source. These companies sell chemicals, mostly manufactured by other chemical companies, rarely under their own label. These distributors are required to provide the MSDS for each chemical from each manufacturer that they sell. a. The largest distributors in the US are VWR (www.vwrsp.com) and Fisher Scientific. VWR has a very convenient MSDS tab on the front page. On Fisher Scientific’s site it is very difficult to find MSDS, so I would use VWR’s site. 3. You can also check with the chemical manufacturers directly. The largest companies with the greatest selection are Sigma-Aldrich, Alfa Aesar, and TCI America. a. All of these companies will have a button or tab for MSDS look-up.

Adapted from EdCC/David Symon CHEM 121 – NSCC Instructor: Maxi Boeckl Fall 2010

b. Sigma-Aldrich (www.sial.com) – after selecting your region, search for chemical name in the search field; after the chemical comes up – the MSDS link will be easily visible. Works more reliably than the MSDS search. c. Alfa Aesar (www.alfa.com) – after selecting the region, go to the pull-down menu “Documents and Reference” and select “MSDS”. d. TCI America (www.tciamerica.com) – there is a MSDS search field right on the home page. 4. Another option is to do a Google or Bing search by typing in “MSDS chemical name”. Often times you end up at one of the manufacturer’s or distributor’s sites, but this way you can also find MSDS’s from smaller manufacturers.

Trouble finding the MSDS for the chemical your chemical? The most common problem is that the chemical is listed using a common name or Trade name on a label and the MSDS is listed under its IUPAC name (formal chemical name). The convenient method to get around this problem is to find the CAS (Chemical Abstract System) number. Each chemical has a unique CAS number that unambiguously identifies that chemical. The easiest place to find the CAS number is on Wikipedia – search by chemical name. Typically the most common synonyms are listed on Wikipidia and you compound should pop up. Once you find the compound, the CAS number will be listed in the table on the right hand side of the page. But chemical search engines like eMolecules (www.eMolecules.com) and ChemBioFinder (www.chemfinder.com) are also helpful. On those two sites, click on more detail or more info to see MW and CAS number after you have found you compound. These will also show you synonyms and manufacturers (ie, where you can find MSDS). With the CAS number in hand, you can go back to any of the sites that provide MSDS’s and go search by CAS number.

Understanding the contents of MSDS Material safety data sheets can be intimidating if you do not understand or are not familiar with the information they contain. In this lesson, we will look at the MSDS and review the information it contains.

MSDS are divided into several sections. The first section generally contains the name of the compound, any possible synonyms, its chemical formula, and its CAS number. Take a look at the sample MSDS for sucrose. You will see that one synonym for sucrose is dextrose; but you probably know it as just plain “sugar”. Other information given are physical properties of the chemical, such as color, density, boiling point, and solubility. Other sections contain information on reactivity, disposal, conditions to avoid, what to do in the case of a spill, and so on. The MSDS also identifies any hazards associated with the chemical and list any special handling precautions and/or protective equipment needed when working with the chemical. Of particular importance is the health, hazard, emergency, and first-aid data. In the health hazard section, you will often find the term LD 50. This term is used as an attempt to quantify the degree of toxicity of a compound. The term LD50 indicates the dose of a chemical that is the lethal dose for 50% of the population. In 2002, the LD50 test was officially banned by the Organization for Economic Cooperation and Development (OECD). While new chemical products must be tested by an alternative method, LD50 data will still be found in current MSDS. For example, strychnine sulfate, a violent poison, has an LD50 of 5 mg/kg when administered orally to rats. That is, if a population of rats is given strychnine sulfate in the amount of 5 mg/kg body weight, 50% of these rats will die. Various abbreviations are used for both the species of animal tested and the mode of administration of the compound:

Animal Tested Mode of Administration

GPG Guinea pig i.m. or mus Injected intramuscularly

MUS Mouse i.p. Injected intraperitoneally (abdominal cavity)

i.v. intravenously

suc. subcutaneously

Therefore, a notation of LD50 (i.p., GPG): 200 mg/kg, would mean that when a population of guinea pigs was given 200 mg of compound per kilogram of body weight via an injection intraperitoneally, 50% of these guinea pigs died.

In addition to LD50, you might see the term LC50. LC stands for “lethal concentration”. This can be used for concentrations of chemical in solution (e.g., water) or the concentration of a chemical in the air.

The trick in looking at LD50’s is to be able to determine whether the compound is a severe poison or not harmful at all. You will see in the MSDS for sucrose that the LD50 is listed. However, we all know that sucrose (table sugar) is not generally considered toxic. Many of the warnings that are used by the manufacturer are stock phrases. For example, the sucrose MSDS suggests that you should induce vomiting if sucrose is ingested. Even through this warning seems ridiculous, you cannot generally ignore the warnings given. The chemicals that are used in the lab are not manufactured to be consumes, so trace amounts of other chemicals can be contained that will be harmful – the warnings are real!

Another important section of an MSDS is the listing of acute and chronic effects. Acute effects are those seen after a short exposure. As a student who may only be exposed to a particular chemical once, pay close attention to acute effects. Chronic effects are due to long-term exposure to a chemical. If you are an employee who works with chemicals day after day, you will also need to be aware of the effects of exposure over time.

One of the goals of this lab exercise is to give you a sense of what these warnings and numbers mean and to help you gain a level of comfort when working with chemicals in the laboratory. One of the major advantages of taking a chemistry lab is for you to learn how to handle chemicals safely. Learning how to read MSDS is a step toward that goal.

Post Lab Report:  Working with your lab partner, answer questions 1-4 on sucrose using the information given in the MSDS provided. (4 points)  Then look up one covalent (organic) compound and one ionic (inorganic) compound and fill out the two forms. (6 points)  Lastly answer questions 5-7. (5 points)

Lab Partner 1: ______Lab Partner 2: ______

Sucrose MSDS

Using the sucrose MSDS provided, find the following information:

1. List two synonyms for sucrose.

2. What is the LD50 for sucrose? How was the LD50 determined; that is, what species was used and what was the mode of administration?

3. What are the acute effects of exposure?

4. What do the MSDS recommend to be done if sucrose is ingested?

MSDS for Inorganic / Ionic Compound

Name of Compound:

Chemical formula:

LD50 and method of determination

What are the acute effects of exposure?

What does the MSDS recommend to be done if this compound is ingested?

Function of the chemical

Source of the MSDS

MSDS for Organic / Covalent Compound

Name of Compound:

Chemical formula:

LD50 and method of determination

What are the acute effects of exposure?

What does the MSDS recommend to be done if this compound is ingested?

Function of the chemical

Source of the MSDS

Additional Questions

5. Assume that the LD50 data for sucrose can be extrapolated to humans. How much sucrose would a 150-lb person have to take orally to be at the LD50 amount? Useful conversion 1.00 kg = 2.2046 lb.

Do the same calculations for your selected compounds. Show all you work. a) Sucrose (g)

b) Chosen ionic / inorganic compound (g)

c) Chosen covalent / organic compound (g)

d) Which chemical is more toxic?

6. Does a larger LD50 indicate a more or less toxic compound?

7. What do you think LD100 means?

Adapted from EdCC/David Symon