Investigation of the Adulteration of Essential Oils by GC-MS

Background:

A lack of regulation about the chemical composition of essential oils and the growing popularity of these oils among consumers presents an urgent need for the accurate characterization of various oil types from a variety of manufacturers. The aim of this paper was to characterize the composition of essential oils bought from a popular retail location, with the goal of understanding the chemical composition and presence of adulterants with potential toxicity.

Methods:

Reported herein is an investigation into the components of a variety of essential oils using gas chromatography-mass spectrometry (GC-MS). The investigation initially focused on two popular oils, tea tree and lavender oil, and then moved to investigate four additional essential oils from the same brand (sandalwood, rose, eucalyptus, and lemongrass).

Results:

Results of this analysis indicated that all six store brand essential oils contained Carbitol (in concentrations from 23% to 35%), and four of the six oils had diethyl phthalate (in concentrations ranging from 0.33% to 16%). These toxicants are particularly concerning because they are known inhalation hazards, and the intended usage of these oils is for aromatherapy (i.e. inhalation).

Conclusion:

These results highlight a potentially significant and under-reported health concern from inhalation of toxic contaminants in the store brand oils, and showcase the need for more regulation and transparency about the composition of these commercial products.

Identification of 15 Phthalate Esters in Commercial Cheese Powder via Cyclodextrin-Promoted Fluorescence Detection

A challenge for detecting phthalates in commercial products such as cheese powders is that the composition of the products is highly complex, and current methods for detection rely on gas chromatography-mass spectrometry, which is not portable and cannot be used by individual consumers at a time and place of their choosing. Herein, we report the development of a new method for phthalate detection in cheese powder using cyclodextrin-promoted fluorescence detection, in which the presence of the phthalate analytes leads to highly analyte-specific changes in the fluorescence emission signal of a fluorophore bound in a cyclodextrin cavity. This method relies on subtle changes in the analyte affinity for the fluorophore and the cyclodextrin cavity and provides for markedly more straightforward sample preparation procedures and an extremely rapid read-out signal, with potential for the development of portable fluorescence sensors. Using this method, we were able to detect 15 phthalate esters with highly analyte-specific responses and at concentrations as low as 0.12 μM, which is well below regulatory levels of concern. Computational investigations strongly support the observed experimental trends.

The Evidentiary Significance of Automotive Paint from the Northeast: A Study of Red Paint

This population study was conducted to assess the frequency of physical, microscopical, and chemical properties of automotive paint chips. Population studies of trace evidence provide valuable analytical data for criminalists to assess evidentiary significance. Two-hundred automotive paint chips were collected from auto body shops from the Northeastern United States. All samples were analyzed using stereomicroscopy, brightfield, and polarized light microscopy. Red paints were targeted for further analysis using a sequence of modern instrumental techniques commonly used by forensic paint examiners: Fourier-transform infrared (FT-IR), Raman, and ultraviolet-visible (UV-Vis) microspectroscopy. The discrimination potential of each analytical method was evaluated by inter-comparing the paint samples. Results demonstrated that macroscopic and microscopic properties were able to differentiate 99.995% of the population (one undifferentiated pair out of 19,900). When combined with either FT-IR or UV-Vis microspectroscopy, all paints were differentiated. The results of this research lead to the conclusion that one would not expect to encounter two indistinguishable paint chips originating from different sources during the investigation of a single event.