ChemIDplus - Part 1

Welcome to Part 1 of the ChemIDplus tutorial. This tour allows you to follow along in the live ChemIDplus site in the right side frame.

Use the arrows below to navigate through the tour. You can also navigate from the "Contents" button above.

Important note: If you'd like to go to a previous section of the tutorial, use the arrows below. Using your browser's back button may cause you to exit the tutorial.

Click the arrow below to continue.

About ChemIDplus

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One of the foundations of toxicology is basic chemical information.

ChemIDplus contains more than 420,000 chemical records with information about names, structures, chemical properties, and toxicity with links to information in other databases. The database is regularly updated.

About ChemIDplus

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ChemIDplus is a great place to start your search for chemical information because you can search by several aspects and it links to all NLM databases, such as PubMed and PubChem, that have information about a particular drug or chemical.

ChemIDplus also links to federal agencies, sites about chemical laws and regulations, and several other relevant resources. The information in ChemIDplus is updated daily and comes from more than 100 sources.

All ChemIDplus Sources

About ChemIDplus

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ChemIDplus has three search interfaces - ChemIDplus Lite, Browse, and Advanced. We've landed at the ChemIDplus Lite simple search box.

What's the difference between the search interfaces? Learn more in the ChemIDPlus Help

You can search for substances with similar chemical structures in ChemIDplus Lite. 

Searching ChemIDplus

On the ChemIDplus page, notice the links for Browse  and Advanced. 

If you're not certain how to spell a particular substance, the browse tool can be very useful. You can also browse by other fields, such as chemical formula. 

For the remainder of this tutorial, we will use the Advanced interface. 

Click Advanced.

In the advanced search interface you may be prompted to download or run Java and enable Marvin to run as an applet in order for the structure search to work. For more information about the Marvin Applet, Java or browser compatibility, see the ChemIDplus FAQs.

There are several search boxes on this page, representing several access points to information in the database. Let's explore. 

Search by Substance Identification

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In the Advanced Search interface, you can search by chemical name or several other facets. Let's start at the top, in the left-side column.

Click the drop-down arrows in the Substance Identification box to explore the options available to you.

If using Name/Synonym, you can enter a common name, trade name, or formal chemical name to search.

Try it out by searching Tylenol as Name/Synonym.

Your search should have taken you to search results including Acetaminophen, the preferred name for Tylenol. 

We'll explore the record pages in more detail later, but for now, click Start New Query to return to the Advanced Search page.

Search by Substance Identification

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You can also search by registry number. Registry numbers refer to the unique identification numbers from the Chemical Abstracts Service. These numbers are up to 10 digits long and are divided by hyphens into three parts.

Select registry number from the drop-down menu and type 58-08-2. Click search at the top.

You should find that this number identifies the substance caffeine.

The substance name may have one or more abbreviations next to it in brackets, such as USP or BAN.

What are those abbreviations?

The registry number (RN) appears under the substance name and is followed by the InChIKey.

What's an InChI?

Search by Substance Identification

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At the top of the full record for caffeine, you should also find:

  • Molecular formula
  • Molecular weight
  • A descriptive note
  • Structure

Many, but not all, records have a chemical structure available.

What is the source of the information in the Note?

Return to the advanced search page by clicking Start New Query rather than your browser's back button.

Search by Substance Identification

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A chemical formula tells us the number of atoms of each element of a substance. For example, water is H2O, and contains 2 hydrogen atoms (H) and one oxygen atom (O) in each molecule. 

To search by a chemical formula, select formula from the drop-down menu in the Substance Identification box and type a chemical formula with hyphens, such as C10-H12.

Notice also the second drop-down menu in the substance identification box. You can use this feature to find all chemicals that start with or contain a part of a name or a particular formula.

Change the drop-down menu to contains. Click search to retrieve a list of substances that contain C10-H12 as the formula.

Approximately how many substances have a chemical formula that contains C10-H12?

Return to the Advanced Search by selecting Advanced at the top, under the ChemIDplus logo. 

Search by Substance Identification

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Another useful search is to search by category. 

Suppose you would like to find substances categorized as antacids. 

Select Category and Starts with

Type antac

Notice that ChemIDplus suggests a search for you. 

Run the search for antacids. You should return a list of approximately 31 antacids.

Open the record for calcium carbonate, and look under the classification tab to confirm it is classified as an antacid. 

Stop and think: how might you use this type of search?

More information on Autocomplete can be found in ChemIDplus Help

Click Start New Query.

Search by Substance Identification

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Let's try a few exercises.

Remember to return to the advanced search screen using Start New Query, rather than your browser's back button.

What substance is identified by registry number 11061-68-0?

A researcher might be interested in finding chemicals that contain a particular group. Approximately how many substances contain Mg-O2?

How many substances start with the name Thiopent?

In some cases, the answer may be approximate because new substances are added daily to ChemIDplus.

Search by Toxicity

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The next type of search you can do is by the toxicity of a substance.

Return to the ChemIDplus Advanced Search screen and click on the info button (the small i) next to Toxicity to read about important toxicity terms.

Which term is used to indicate the lowest dose of a substance reported to have caused death in animals or humans?

Search by Toxicity

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Suppose you wanted to answer the following question:

What substances cause death in 50% of the human population at dose of less than 50 mg/kg through any route of exposure?

In the the Toxicity box, select LD50 as the test.

Change the next drop-down menu to "less than."

Type 50 in the query box.

Select human in the species drop-down menu and leave the route and effect set to any.

Click search at the top or bottom of the page.

You should have retrieved 5 records. You may recognize some of these substances as highly toxic chemicals, such as sarin or mustard gas.

Search by Toxicity

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Click on Sarin to open the Full Record for the substance.

Under the basic substance information, click the Toxicity tab

Find the Human LD50 value. Notice the route of exposure, effect, and source of information. Where possible, the source is linked to the citation in PubMed. 

Click Start New Query to return to the advanced search page.

Search by Physical Properties

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Moving down the page, we can also search by several physical properties.

Click on the drop-down menus in the Physical Properties box to explore the search options. You can also click on the info button to learn more about physical properties.

Using physical properties can help to identify an unknown substance or generate a list of substances that share certain physical characteristics.

Search by Physical Properties

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Let's search for substances with a boiling point between 200 and 202 degrees.

Tip: to search for a range of values, select between, and type the range with either a space or dash between the two values.

In the Physical Properties box, select boiling point and between. Type 200 202.

Click search at the top or bottom of the page.

Notice that you can change the display to show more results.

Search by Physical Properties

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You should retrieve approximately 60 substances.

Open the record for Tetraethyl Lead. 

Click the Physical Properties tab to verify that this substance meets your search criteria. 

Click Start New Query to return to the advanced search page.

Search by Locator Code

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The next search box on the page is for Locator Codes. Locator Codes refer to a database or resource with data present in ChemIDplus.

Click on the drop-down menu in the Locator Codes box to see a long list of resources that can be searched from ChemIDplus, which includes resources from NLM and other agencies.

How can you tell what the locator codes are?

Click the info (i) button in the Locator Codes search box. 

This will open the Locator Codes section of ChemIDplus Help. 

There is a link to the Alphabetical List of Locators Used in ChemIDplus. Click the link for a full list of locator codes, their full names and descriptions. 

Substances on the California Proposition 65 list, those known to the state to cause cancer or reproductive toxicity, can be found using locator code CA65

Search by Locator Code

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You can use Locator Codes as a limit for your searches. For example, you may want to see only records with information from NIOSH (The National Institute for Occupational Safety and Health). It could also be used to explore the overlap between databases. 

Locator codes can also be used in the Substance Identification search box. 

Try out the Locator codes with a quick exercise.

How many substances are listed on Title VI of the Clean Air Act?

This search generates a list of substances from Title VI of the Clean Air Act, which added provisions to the Clean Air Act for protecting the ozone layer. 

Search by Locator Code

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Select Methylchloroform from the results list. 

Click the Links to Resources tab.

These links point to additional resources for this chemical.

The links are divided into three categories. 

First, there are National Library of Medicine associated databases, such as PubMed or the Hazardous Substances Database (HSDB).

Next are links to regulatory agencies and scientific lists that contain information about the chemical, like Title VI of the Clean Air Act (CAA2) or the EPA High Production Volume chemicals (HPV). 

Other Resources point to external federal, state or scientific sites with information of interest for the chemical.

Clicking on the info button next to a locator name will provide a description of the resource.

Clicking on the Locator hyperlink will open a new window with data from a given resource, as close to the level of the substance as possible.

Search by Locator Code

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For example, click on the link to HSDB under NLM Resources. It should open in a new window. 

Notice that it opens to a substance called 1,1,1- Trichloroethane. 

Is this a synonym of Methylchloroform or did something go wrong?

Switch back to your ChemIDplus window and click the Names & Synonyms tab. Scan the list to verify that they are indeed synonyms. 

Start a new query. 

Search by Molecular Weight

You can also search by molecular weight. A researcher may want to find what substances exist within a particular molecular weight range.

The molecular weight search is on the bottom of the right side.

Let's try this out. Be sure you have cleared any previous searches by clicking Clear at the top or bottom of the page.

Approximately how many substances have a molecular weight between 58 and 60? 

Notice that the molecular weight appears below the structure drawing in the search results. For example, the molecular weight of acetamide is 59.0675.

Click Start New Query to return to the advanced search interface.

More on Searching

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You can combine search fields on the advanced search page, but keep in mind that ChemIDplus will automatically AND your search fields.

Try this out by finding substances that have a melting point between 212-220º AND have a molecular weight greater than 400.

You should retrieve about 24 records.

Click Start New Query to return to the advanced search page.

More on Searching

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Notice that in each search category, ChemIDplus indicates how many records have data available in that category at the bottom of the box. In other words, not all substances have the same data fields in the record.

Keep this in mind if you combine search fields.

Which type of data is available for the fewest records?

End of ChemIDplus Part 1

You've completed Part 1 of the ChemIDplus Tutorial! 

In Part 2 we'll learn about searching by chemical structure. 

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