What Is ICP-MS Testing?

How ICP-MS works

1. Digestion. The sample is broken down in acid, often by microwave heating in a closed vessel, so every element ends up in solution (FDA EAM).
2. Ionization. The solution is sprayed into an argon plasma, which turns the elements into ions.
3. Mass separation. A mass spectrometer separates the ions by mass-to-charge ratio, so each element is counted on its own.
4. Quantitation. Results are read against calibration standards, with internal standards to correct for drift and matrix effects (EPA Method 200.8).

What ICP-MS is used for

Drug products. FDA’s guidance implements ICH Q3D and USP <232> and <233>, which set limits for elemental impurities in drug products and describe how to test for them (FDA guidance). Q3D places arsenic, cadmium, mercury and lead in Class 1: human toxicants that often come from mined excipients (ICH Q3D(R2)). Impurities can also come from equipment and container closures.

Food and water. FDA’s Elemental Analysis Manual uses ICP-MS for lead, cadmium, arsenic, mercury and other elements in food (FDA EAM), and EPA Method 200.8 uses it for trace elements in ground, surface and drinking waters (EPA).

Source: ICH Q3D(R2) permitted daily exposures (FDA). Limits are per day of drug taken, so the allowed concentration depends on the daily amount.

ICP-MS vs ICP-OES vs HPLC

ICP-OES also uses a plasma but measures the light each element gives off; ICP-MS counts ions by mass and generally reaches lower detection limits. USP <233> describes both: Procedure 1 is ICP-OES and Procedure 2 is ICP-MS (USP <233>). HPLC and LC-MS are different tools. They separate and measure molecules, such as the active drug in a potency test. An HPLC assay can’t tell you how much lead a product has, and ICP-MS can’t tell you its potency.

Who uses ICP-MS testing?

• Compounding pharmacies and 503B outsourcing facilities checking APIs, excipients or finished products for elemental impurities.
• Businesses checking raw materials, supplements or cosmetics for heavy metals. FDA notes its food method isn’t validated for mineral supplements or cosmetics without extra verification (FDA EAM), so each sample type needs a checked method.
• Consumers who want to know whether a product contains heavy metals.

Testing at Renew Lab Group

Our Houston lab runs ICP-MS alongside HPLC and LC-MS potency and purity testing, toxicology, LAL endotoxin, microbiology, TOC and extractables/leachables. See our HPLC testing lab, compounding pharmacy potency testing, testing for individuals, toxicology testing and lab testing FAQ. To request testing, call 936-379-5515 or email info@renewlabgroup.com.

By Renew Lab Group, Houston, Texas. Published November 2, 2026.