A Complete Solution for Forensic Analyses

By: Patrick Myers, Reporter EU Volume 25

Patrick Myers
pmyers@sial.com

Forensic science encompasses a very broad range of analytes and analytical techniques. Sigma-Aldrich offers the standards and analytical tools required for quantitative analyses in this expansive field. Our offerings include standards for drugs of abuse testing, therapeutic drug monitoring, explosives determination, fire debris analysis, biogenic amine determination, and even snake venom standards.

All of these standards are subject to the stringent manufacturing processes and strict quality control mechanisms you expect from Sigma-Aldrich. Standards are packaged in convenient, secure vials, bottles, or ampules and are generally available for immediate shipment.

The Sigma-Aldrich website is your best resource for these standards. You can search the website for standards by compound name, CAS#, molecular formula, substructure or synonyms. Price, availability, chemical properties, functions, and safety data are all included for each product.

We also offer tools for sample collection, preparation, and analysis. Solid Phase Microextraction (SPME) is an increasingly popular method of extracting analytes directly from the sample matrix and concentrating them for analysis. Solid Phase Extraction (SPE) offers many advantages over more traditional liquid-liquid extraction. SPME fibers and SPE tubes are available for the extraction of most analytes from most matrices. Supelco Technical Service can help you determine the correct fiber or tube for your application.

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Drug Standards

Sigma-Aldrich offers over 2000 drug compounds available as neat and diluted standards. These include the true illicit drugs like heroine and cocaine, therapeutic drugs that are commonly abused like the benzodiazepines, active components of natural products, and drug metabolites. Most drugs of abuse and many therapeutic drugs are included.

Analyses of drugs of abuse are done by both capillary GC and HPLC. Most screening methods use capillary GC. As shown in Figure 1, Equity™-1701 columns provide a unique selectivity for this common analysis.

Figure 1 Unique Selectivity of Drugs on Equity-1701 (28372-U)

HPLC can be used for drug screening and when monitoring for metabolites of drugs. The Ascentis HPLC columns are ideal for these analyses. They are built on the purest silica available, have very high phase coverage and exhaustive endcapping. This all adds up to the ideal columns for the analysis of basic drugs. Figure 2 shows the diffi cult separation of methadone and its metabolite, 2-ethylidene- 1,5-dimethyl-3,3-diphenylpyrrolidine on an Ascentis C8 column.

Figure 2 Separation of Methadone on Ascentis C8 (581424-U)

The United States Pharmacopeia (USP) oversees the analysis of therapeutic drugs. Most of the HPLC and capillary GC columns described in the USP monographs are available from Supelco. Many of the USP methods require the use of packed GC columns. Supelco is the premier supplier of packed GC columns.

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Explosives Standards

Energetic materials monitoring is a growing fi eld. Cleanup of soils contaminated with explosives is a priority for both the US EPA and the US military. There are estimated to be several thousand sites comprising up to 25 million acres of potentially contaminated land. Soil must be monitored before remediation to determine the extent of contamination and after remediation to clear it for replacement.

The entire range of compounds regulated in US EPA Method 8330 is available as single component standards, as a kit of single component standards, and as two multicomponent mixes.

Explosives analysis represents an excellent opportunity for using SPME. This technique allows the solventless extraction of explosives from aqueous matrices whether solid or liquid. Figure 3 shows the GC analysis of 12 explosives extracted from an agitated soil/water slurry using SPME.

Figure 3 Analysis of Explosives in Soil Using SPME (57310-U)

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Standards for Fire Debris Analysis

Supelco offers multiple standards for fi re debris analysis including several gasolines, fuel oils, military fuels, and kerosene. These can be supplemented with any of hundreds of solvent standards as required.

The current methods of extracting accelerant compounds from fire debris include several methods that concentrate the sample before analysis such as, solvent extraction, dynamic headspace concentration and static headspace concentration. These methods are cumbersome, timeconsuming and require the use of hazardous solvents. The use of SPME to extract accelerant compounds from fire debris, as shown in Figure 4, is faster, simpler, more economical and more sensitive.

Figure 4 Accelerant Compounds Extracted from Fire Debris Using SPME(57300-U)

Sigma-Aldrich can provide the standards, sample preparation, analytical tools and consumables you require for forensic analyses.

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