The Laboratory Notebook

Answering important questions about quality.

By Robert Green

The theme of this edition of the Laboratory Notebook is elemental analysis. This phrase refers to the analysis of the elements listed on the Periodic Table of Elements, primarily minerals and metals. These include items that are beneficial as nutritional supplements, such as calcium and iron, as well as those that can be harmful, such as lead and mercury. This month’s questions relate to the elemental analytical technique ICP-MS, heavy metal contamination and California’s Proposition 65.

Q. I have seen reference to an analysis technique called “ICP-MS” for testing minerals and metals but I am unfamiliar with it. Can you explain it?

A. ICP-MS is an acronym for Inductively Coupled Plasma Mass Spectrometry. This is an extraordinarily precise, accurate and fast analytical technique for the determination of metals and minerals in liquid and solid samples.

For precision and accuracy, the ICP-MS detection limit for most elements is in the range of parts per trillion (ppt). How much is a part per trillion? That’s 1 in 1,000,000,000,000, or one penny in a billion dollars! For speed, an ICP-MS can qualify and quantify virtually every element in the Periodic Table of Elements in under two minutes. So how does it work?

The heart of an ICP-MS is its plasma. Plasma is defined as a gas consisting of ions, electrons and neutral particles. In an ICP the plasma is over 10,000 degrees Fahrenheit (that’s about the temperature of the surface of the sun). At this temperature virtually all molecules in a sample are broken up into their component atoms.

Next, the component atoms must be analyzed. The typical ICP-MS configuration uses a quadruple mass spectrometer for this. A mass spectrometer acts as a mass filter that separates ions according to their mass/charge ratio. These ions are then detected, multiplied and counted using fast digital electronics. Sophisticated software then interprets this data and reports the results.

ICP-MS is now considered the instrument of choice in elemental analysis. Many labs do not yet have this instrument because it is extremely expensive to acquire (they can run over $200,000) and operate (anything that generates that much heat must be). Nevertheless, if accurate metals analysis is important this technique is the way to go.

Q. I had my supplement product tested for heavy metals and the result showed a high level of lead, which is not a product ingredient. Can you tell me the problem this poses and how the lead got there?

A. Heavy metals are defined as chemical elements with a specific gravity at least five times that of water. The most commonly discussed are lead, mercury, arsenic and cadmium. Some heavy metals, such as zinc, copper, chromium, iron and manganese, are required by the body in small amounts, but can be toxic in larger quantities. Heavy metals can cause all sorts of health problems, from mental retardation to cancer. Lead can replace hemoglobin in the blood and cause anemia.

Heavy metal contamination is a worldwide problem and can be found in soils, water and air. Most contamination comes from various industrial sources, including electroplating plants, mining, nuclear and electronics industries, metal finishing operations, tanneries and industrial processes utilizing metals as catalysts. Certain agricultural practices also introduce contamination. For example, certain fertilizers and pesticides contain heavy metals. Sometimes these metals are purposefully included to increase effectiveness, while other times they are naturally occurring contaminants or introduced when waste materials are used to formulate fertilizer products. The use of sewage sludge in farming also contributes to the problem, as does the use of contaminated water. Heavy metals can also be introduced during the manufacturing process.

Heavy metals may enter an organism via food, water or air. Heavy metals are absorbed and concentrated in many crops, which are then consumed by humans. Once inside the organism, heavy metals compete with and displace essential minerals such as zinc, copper, magnesium and calcium, and interfere with system function.

The bottom line is that heavy metal contamination is a serious problem, which can come from various sources and is possible in every product run. The fact that several product runs are clean can give no assurance that the next will be contaminant-free. We have tested a particular product for years without incident and then, most unexpectedly, we found a contaminated lot. Heavy metal testing should be a part of every quality protocol.

Q. I hear a lot of talk about “Proposition 65.” Would you please tell me what the fuss is all about?

A. Proposition 65 refers to the California statute entitled, The Safe Drinking Water and Toxic Enforcement Act of 1986. This was a voter initiative passed to address citizen concerns about exposure to substances, which cause cancer or reproductive toxicity. (It was designated as Proposition 65 in the California election and that name stuck.) The law prohibits businesses from discharging these chemicals into sources of drinking water. But a much broader effect of the Act is its requirement that warnings be given to individuals exposed to these chemicals. Since exposure can occur from the manufacture or sale of consumer or commercial products containing these chemicals, Proposition 65 affects all businesses with 10 or more employees that either manufacture or sell products in California. As such, the reach of Proposition 65 goes far beyond California’s borders.

Under Proposition 65, businesses are required to provide a “clear and reasonable” warning before knowingly and intentionally exposing anyone to a listed chemical. This warning can be given by a variety of means, such as by labeling a consumer product. Therefore, businesses that manufacture or sell products in California must first determine if those products contain any listed chemical, and if they do, take appropriate action.

Proposition 65 may be enforced by law enforcement officials and, if they do not act promptly, any citizen. As you can imagine, this has become a boon to lawyers and created a new industry in California.

Proposition 65 is of particular concern to nutritional supplement companies since heavy metals are on the target list and heavy metal contamination occurs from time to time. ICP-MS, with its extraordinary sensitivity, is the method of choice for heavy metal analysis for Proposition 65 purposes. Every day more companies, which sell into California are adding heavy metal analysis to their quality control procedures to be sure they will not run afoul of Proposition 65.NW