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Posts Tagged ‘SIM’

Polycyclic Aromatic Hydrocarbons (PAH) in Shellfish

Friday, May 28th, 2010

Polycyclic Aromatic Hydrocarbons (PAH) in Shellfish

Columbia Analytical Services, Inc. has extensive experience testing for low levels of Polycyclic Aromatic Hydrocarbons (PAH) in shellfish. Sensitive and selective techniques were developed over ten years ago and have been refined and improved on a continuing basis. In addition to the analysis for the common parent compounds, levels of the associated alkylated homologs can also be determined.

This analysis is typically performed using Gas Chromatography/Mass Spectrometry (GC/MS) operated in the Selective Ion Monitoring (SIM) mode. Key to the analytical procedure is proper sample preparation, which begins with shucking, compositing (as appropriate to the project plan), and homogenization via mechanical mixing. The preliminary preparation must be performed under clean laboratory conditions to prevent common PAH contamination. Decontamination of sample preparation equipment is performed and monitored closely to assure clean conditions. The sample homogenate is a homogenous slurry when prepared correctly. The homogenization techniques performed by Columbia Analytical have been inspected and approved by various organizations (e.g. US EPA, other federal government and state regulatory agencies, private industries, consultants, etc.) The data results for these projects were subjected to thorough government, public and private scrutiny.


Analytical Testing for 1,4-Dioxane

Tuesday, January 26th, 2010

1,4 Dioxane Testing1,4-Dioxane (dioxane) is a chemical of concern for its potential health effects as a carcinogen and irritant. It is commonly found in personal care products such as detergents, shampoos, body lotions, and cosmetics, and is widely used as an industrial solvent and stabilizer in manufacturing processes (e.g., electronics, metal finishing, fabric cleaning, pharmaceuticals, herbicides, pesticides, antifreeze, paper, etc.). Currently, there are no established limits on the amount of dioxane in personal care products nor is it specifically regulated in manufacturing wastewater streams that may impact the surrounding environment. Manufacturers of personal care products should conduct laboratory analysis to determine the levels of dioxane in their products, and manufacturers using dioxane in their processes should analyze their waste streams for possible dioxane content.


Selective Ion Monitoring (SIM) for Low Level Applications in Vapor Samples

Friday, October 3rd, 2003

Selective-Ion-Monitoring-for-Low-Level-Applications-in-Vapor-SamplesGas chromatography/mass spectrometry (GC/MS) is the method of choice for the identification of volatile organic compounds (VOCs) in vapor samples (e.g. EPA methods TO-14A and TO-15). As various state and federal agencies more frequently require facilities to address risk-based concentrations, such as the low level preliminary remediation goals (PRGs), they find that the standard method is not able to reach the ultra-low levels needed. To address these requirements, CAS’ Simi Valley, California lab has developed a method using selective ion monitoring (SIM) to measure the compounds. SIM is a sensitivity enhancement technique, where the mass spectrometer is programmed to scan for only those ions that are pertinent to the compounds of interest (2-3 mass ions scanned per compound) while ignoring non-essential ions. The mass spectrometer becomes a highly sensitive compound-specific detector.

The driving force for the lower limits has been health risk assessment activities in the indoor and ambient air arena. The exposure criteria for many compounds are being re-evaluated constantly. A recent symposium sponsored by the Groundwater Resources Association (GRA) on subsurface vapor intrusion to indoor air has recommended that the SIM analytical technique be used. For example, trichloroethene (TCE) will have a reporting limit of 1.0 mg/m3 (0.19 ppbv) using the standard full scan method. In contrast, the reporting limit of 0.05 mg/m3 (0.0093 ppbv) for TCE will be achieved with the SIM technique. This meets or exceeds most risk-based concentration criteria. Lower limits are occasionally requested and are reviewed on a case-by-case basis.


Low Level Analysis of 1,4-Dioxane by EPA Method 8270C SIM with Large Volume Injection

Friday, April 4th, 2003

Low Level Analysis of Dioxane1,4-Dioxane has been used for many years as a stabilizing agent in the production of chlorinated solvents to prevent breakdown during manufacturing processes. It is also present in many household products like soaps, shampoos, baby lotion and cosmetics.

Over the past few years 1,4-Dioxane has garnered increased attention due to it’s presence in groundwater at several California locations and because there is little scientific data available on the longterm effects on human health. An additional concern is that traditional remediation technologies used for sites contaminated with chlorinated solvents are ineffective at removing 1,4-Dioxane.1