A bottle of olive oil or a tanker of refined soybean oil looks simple enough on the label, but at the parts-per-billion level, it's a surprisingly complicated matrix to analyze. Trace metals in edible oils matter for two very different reasons — food safety and shelf life — and both push laboratories toward lower and lower detection limits. For labs running ICP-OES or ICP-MS on oils, that means calibration standards have to keep up.

Two reasons trace metals matter in oils

The first reason is toxicology. Regulatory bodies including the EU (Commission Regulation (EU) 2023/915) and Codex Alimentarius set maximum levels for lead, cadmium, arsenic, and mercury across food categories, and fats and oils are no exception — lead limits for most fats and oils sit near 0.1 mg/kg, with correspondingly tight limits for the other regulated elements. Meeting these limits with confidence requires a method whose detection limit sits comfortably below

If your lab only ever tests food destined for one country, you calibrate to one set of limits and move on. The moment a product crosses a border, that gets more complicated — and the reference point most of the world works from is Codex Alimentarius.

What Codex actually is

Codex Alimentarius isn't a single country's food law. It's a joint FAO/WHO body that sets internationally recognized food standards, and the relevant one here is the General Standard for Contaminants and Toxins in Food and Feed (CXS 193-1995). First adopted in 1995 and revised repeatedly since, it lists maximum levels (MLs) for contaminants — including toxic elements like lead, cadmium, arsenic, mercury, and tin — across a wide range of food commodities.

Because Codex standards are referenced under the WTO's Sanitary and Phytosanitary (SPS) Agreement, they function as the default benchmark in international food trade, even in countries that also maint