Lab Science News

Background

Total Volatile Organic Compounds (TVOC) may be evaluated when building designers/managers are pursuing the Leadership in Energy and Environmental Design Green Building Rating System for New Construction (LEED-NC) EQ Credit 3.2. The latest LEED-NC guidance document specifies that the maximum allowed concentration of TVOC measured in a building (post construction, pre-occupancy) is 500 µg/m³; the guidance also mentions using the sampling/analytical methods in the US EPA Compendium of Methods for the Determination of Air Pollutants in Indoor Air. However, none of these sampling and analytical methods address TVOC in particular, and thus the existing methods must be modified. In addition, TVOC is not defined (in terms of boiling point range, etc.) in the latest LEED-NC guidance and therefore is left open for interpretation; historically, many definitions of “TVOC” exist in literature.

For TVOC measurement, the analytical technique used must always reference one compound for calibration purposes. All compounds detected are then assumed to have the same response factor as the calibration compound. For instance, handheld instruments are most often calibrated using isobutylene or methane, and laboratory-based methods may reference TVOC as hexane (C6), toluene, or some other chemical species.

In practice, indoor air quality practitioners may use several different techniques for evaluating TVOC in buildings. Each sampling & analytical method has its own benefits and drawbacks, cost implications, and applicability.

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For years, dietary supplements have been scrutinized by the media for being marketed as “snake-oil” cure-alls, potentially containing components considered harmful to consumers. Under-regulation by the Food and Drug Administration (FDA) lead to concerns that these products did not fall under the same regulatory requirements as pharmaceuticals. Until now.

New FDA regulations for the dietary supplement industry aim to eradicate consumer concern and health risks associated with these products. Dietary supplement manufacturers and distributors are now required to follow Good Manufacturing Practices (GMPs) similar to those of the pharmaceutical industry. The FDA 21 Code of Federal Regulations (CFR) Part 111 was established to insure the identity, purity, quality, strength, and composition of dietary supplements and applies to those involved in the manufacture, packaging, labeling or holding of a dietary supplement, with the exception of retail establishments selling directly to consumers.

The federal government is taking a tiered approach to enforcement: companies with more than 500 employees were required to become compliant by June 2008; companies with 21-499 employees must become compliant before June 2009; and companies with fewer than 20 employees will need to be compliant by 2010.

To become compliant with the GMP guidelines, passed in 2007, dietary supplement companies need to perform analytical testing of their products. Analytical laboratory analysis falls under the category of “manufacture” as defined by FDA CFR.  Therefore, if testing is not performed the dietary supplement company will be considered non-compliant regardless of the reason for not testing. Reasons for not testing range from it being cost prohibitive to it’s impossible as an option for raw materials, in-process or final products. Those non-compliant and unable to meet GMP guidelines will run the risk of not being able to sell their products due to regulatory agency action. This may result in some companies going out of business or, at the least, an increased need for analytical testing.

In some ways, GMPs for dietary supplements have been considered to be more strict than those for pharmaceuticals. For example, many pharmaceutical compounds can be considered “pure” if they meet 90-98 percent of the requirement. Purity constraints for dietary supplements can be as much or more than 100 percent as a requirement. The GMPs for dietary supplements are a combination of GMPs for both food and drugs. The abundance of new regulations may be a response to the public scrutiny the dietary supplement industries have received in recent years.

GMP compliant analytical testing for GMP guidelines may include residual solvent and heavy metals analysis, water determination by Karl Fischer, and microbial limit testing. These tests are designed to ensure product quality and consumer safety, but there is a need for identity testing and potency as well. Identity and potency will confirm for manufacturers that the product label accurately reflects the actual ingredients as well as potency of each batch or lot of product.  In other words, “it is what it is” and the manufacturer has the compliant analytical quality control laboratory documentation to prove it.

This new challenge for production will require substantial new testing in order to maintain compliance. Some dietary supplement companies have already found that outsourcing the testing, though thousands of dollars per year, is a more sensible business strategy than investing millions developing and maintaining their own compliant laboratories. When outsourcing analytical testing to laboratories, the FDA requires the outside lab to be cGMP compliant and FDA inspected. The Quality Unit of compliant laboratories will be able to readily supply information including documentation of quality systems and FDA inspection reports.

Manufacturers may want to assess the most cost effective and efficient means to deal with these new FDA regulations.

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References:

FDA Issues Dietary Supplements Final Rule

http://www.fda.gov/bbs/topics/NEWS/2007/NEW01657.html

FDA 21 CFR part 111

http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?CFRPart=111&showFR=1FDA

The Massachusetts Department of Environmental Protection (MassDEP) recently updated and finalized their Air-Phase Petroleum Hydrocarbons (APH) analytical method. The APH method, which had been in draft format since February 2000, was completed last year by a MassDEP Workgroup and approved after a month long public comment period in December 2008. The committee was comprised of MassDEP personnel, laboratory experts and data users.

The most significant updates to the APH method include:

• Analyte List Revisions - 2-Methylnaphthalene was removed from the target analyte list and is no longer considered an air-phase petroleum hydrocarbon. In addition, laboratories will no longer report the “unadjusted” hydrocarbon ranges.
• Calibration Standards Revisions - Indene, hexylcyclohexane and 1-methynaphthalene were removed as hydrocarbon range calibration standards/retention time markers, due to poor performance and stability in the whole air matrix.
• Standard Preparation – The newly revised method will only allow vapor phase standards to be used for calibration. (Previously, in the draft method, methanol based standards were allowed.)
• Calibration & Quality Control Requirements, Holding Time and Performance Standards – Many small changes were made in order to make the APH method consistent with EPA Method TO-15.

The MassDEP APH method is currently the only existing method to look at vapor phase hydrocarbons in a risk based corrective action approach (i.e. with fractionated aliphatic and aromatic ranges). Going beyond EPA Method TO-15 or a traditional total petroleum hydrocarbons (TPH) approach, this method provides more specific information about the type of hydrocarbon contamination at a site.

As an example of the utility of the APH method, Figure 1 shows the total ion chromatogram for a soil gas sample collected at a site impacted by historical subsurface petroleum product contamination. For this example, all the APH target compounds (1,3-butadiene, benzene, toluene, ethylbenzene, xylenes, MTBE, and naphthalene) as well as several other petroleum indicator species (1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, n-nonane, n-decane, n-dodecane, n-undecane) were not present above the laboratory reporting limit. However, as is visually evident, there was still a strong weathered petroleum pattern present in the sample. The hydrocarbon ranges reported in the APH method were able to capture this information which otherwise might have been overlooked in a basic review of the numerical results.

Figure 1. - Total Ion Chromatogram of Real-World APH Sample

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References (Current as of December 2008)

1. MassDEP Method for the Determination of Air-Phase Petroleum Hydrocarbons (APH), December 2008. Available at: http://www.mass.gov/dep/cleanup/laws/qaqcdocs.htm#IV

2. MassDEP Standard Operating Procedure for Indoor Air Contamination, SOP-BWSC-07-01, August 2007 (made available April 2008). Available at: http://www.mass.gov/dep/cleanup/laws/policies.htm#iasop

3. MassDEP Indoor Air Sampling & Evaluation Guide, WSC Policy #02-430, April 2002. Available at: http://www.mass.gov/dep/cleanup/laws/policies.htm#indair

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View the APH method flyer (PDF file)

Read about testing for petroleum hydrocarbon contaminations

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Organochlorine pesticides (OCPs) have a long history of use in the United States and around the world. Although the production and use of many OCPs has been banned since the 1970s, the compounds are extremely persistent in the environment and are known for accumulating in sediments, plants and animals. OCPs have a wide range of both acute and chronic health effects, including cancer, neurological damage, and birth defects. Many OCPs are also suspected as endocrine disruptors.¹

Due to the need to monitor levels of OCPs, significant research and development has taken place over the last 40 years. This has culminated in two primary methods used by the Environmental Protection Agency (EPA) to regulate the transport and fate of OCPs; EPA Method 1699 and EPA Method 8081.

EPA Method 1699, isotope dilution and high-resolution mass spectrometry, is considered the ultimate in pesticide analysis relative to sensitivity and selectivity, but can be cost prohibitive.

EPA Method 8081 is a gas chromatography method that employs electron capture as a means of detection. To achieve some level of selectivity, the method is run in dual column mode with two dissimilar analytical columns. It has been well documented that the use of ECD can lead to false positives or high biases in the results generated by this method.²

This lack of selectivity is especially apparent when polychlorinated biphenyls (PCB) are present in the sample.

 
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The increase in regulatory oversight at vapor intrusion sites nationwide, as well as recent publication of Federal and local vapor intrusion guidance documents and screening levels has led to a need for reliable air phase (indoor air and sub-slab/soil vapor) data at extremely low concentrations. This paper will explore and discuss the importance of media cleanliness and certification to achieve typical low level data quality objectives.

Several potential pathways of media contamination will be examined, including: canisters, flow controllers/critical orifice assemblies, vacuum gauges, and canister pressurization/fill stations in the laboratory.

Several contamination situations will be explored and quantified. The resulting data will be used to support laboratory and field sampling best practice recommendations.

Read the complete air sampling media cleanliness case study… (Acrobat PDF)