The laboratory notebook: answering important questions about quality.
Q. My chondroitin sulfate was tested by my customer using the USP methodology and it failed. I had it tested by size exclusion chromatography and it happily passed. My customer says once the USP promulgates a method we have no choice but to use it. Is this so?
A. Absolutely not. USP methods for dietary supplements are not binding. While they should be given serious consideration, their use is not mandatory, and in many cases, not advisable. The situation with chondroitin sulfate is a case in point.
As we have discussed in this column, chondroitin is not a single entity, but rather, a variable length polymer. Further, the chondroitin sulfate in commerce is not a single molecular entity; it is a mixture of polymers of different sizes in any given sample. Therefore, a suitable method of analysis used for material in commerce must take these factors into consideration. A method that only works for a particular length of polymer is, in our opinion and with all due respect to the USP, not suitable for general use in the supplement industry.
The USP methodology employing CPC is only capable of accurately measuring chondroitin if the sample consists of polymers that are very similar in size to the standard being used. This method works great for the manufacturer whose product is designed to consist of a specifically limited polymer length. However, when testing chondroitin found in commerce the method must work on samples of various size polymers, and the CPC method does not. Use of the CPC method results in the failure of very good material. In addition, other ingredients/excipients present in a finished product can interfere with the flocculation/turbidity process of the CPC procedure, so it is not suitable for the analysis of finished products.
The fact that the USP produces a method of analysis does not mean that method is appropriate in all situations. The job of an analytical lab is not to blindly follow any particular method, but rather, to first confirm that a method to be employed is appropriate for the situation at hand.
Q. The analytical results of a sample of CoQ10 I purchased showed material of low purity. At the insistence of the manufacturer, I got detailed analytical data, which indicated that, in addition to CoQ10 present, there was also CoQ6 and CoQ7, thereby accounting for the low level of CoQ10. The manufacturer said this was not possible. Can it be?
A. Whenever anyone in our industry says an unsatisfactory analytical result is not possible, a further investigation is in order. Let's first get a basic understanding of CoQ10.
CoQ10 belongs to a family of compounds known as ubiquinones. Ubiquinones are found naturally in every living cell in the human body. The name ubiquinone refers to the ubiquitous presence of these compounds in living organisms and their chemical structure, which contains a functional group known as a benzoquinone.
A coenzyme is a substance needed for the proper functioning of an enzyme. (Enzymes are critical molecules that speed up the rate at which chemical reactions take place in the body.)
Ubiquinones are fat-soluble molecules with anywhere from one to 12 isoprene (5-carbon) units. The ubiquinone found in humans, ubidecaquinone, has 10 isoprene units (a total of 50 carbons), ergo, the "10" in CoQ10. So now you know where the name CoQ10 came from.
CoQ10 is used by cells to produce energy needed for cell growth and maintenance. It is also used by the body as an antioxidant, which is a substance that protects cells from chemicals called free radicals. (Free radicals are highly reactive chemicals that can damage important parts of cells, including deoxyribonucleic acid--DNA.)
CoQ10 is naturally present in small amounts in a wide variety of foods, but is particularly high in organ meats such as heart, liver and kidney, as well as beef, soy oil, sardines, mackerel and peanuts. Studies have shown our dietary intake of CoQ10 is very small--in the milligram range.
CoQ10 is generally manufactured (or as we in the chemical business say, synthesized) in one of two ways--by chemical synthesis or fermentation. In chemical synthesis, Solanesol, extracted from plant material, is converted to a nine-isoprenoid compound and then reacted with hydroquinone to produce CoQ10. In fermentation, microorganisms are stimulated to produce repeated mutations, thereby enhancing their capacity to synthesize CoQ10. This fermentation process can consist of yeast or bacteria.
As to your question, a sample of CoQ10 could indeed contain other CoQs. These other molecules could form during synthesis and escape removal during the post synthesis clean-up process. Your manufacturer's blanket denial of this possibility is incorrect.
Q. My supplier said he tested his raw material for heavy metals using the technique ICP-OES and none were detected. My lab used ICP-MS, and it found small amounts. Which technique is more accurate?
A. ICP-MS, and here's why. Both methods have the same front end, ICP. This stands for Inductively Coupled Plasma. 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, and here is where the two techniques diverge. When a sample is introduced into the plasma, nearly all of the elements in the sample become highly excited by the energy from the plasma and begin emitting light. ICP-OES uses this phenomenon for the analysis. Each element emits light with a wavelength (spectrum) specific to that element. It is therefore possible to analyze and identify the elements in the test sample by separating the emitted light into its spectral components using a high-performance spectrometer. Logically, OES stands for optical emission spectrometry.
On the other hand, the typical ICP-MS configuration uses a quadrupole mass spectrometer for the analysis. 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. MS stands for mass spectrometry.
Both techniques are sophisticated and accurate. The big difference lies in the limit of detection (lod). The limit of detection is derived from the smallest amount that can be detected with reasonable certainty for a given analytical procedure. Here ICP-MS wins hands down. The sensitivity of ICP-MS is generally 100 times, and can be 1000 times that of ICP-OES. ICP-MS is the newer technology, and the instrumentation is significantly more expensive, so there are less of them out there. Nevertheless, ICP-MS is truly state-of-the-art for elemental analysis.
Robert S. Green is the president of Integrated Biomolecule Corporation/IBC Labs, a biotechnology company that conducts nutritional supplement ingredient and finished product testing and provides research, development, production and technical marketing services. He can be reached at 520-219-2900; Fax: 520-219-6090; E-mail: email@example.com; Website: www.integratedbiomolecule.com.
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|Title Annotation:||Quality Focus|
|Date:||Sep 1, 2004|
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