Here are some recent publications that you may find interesting. If you would like more information, just go to the abstract and send the author a note.
David S. Cho, Stephen C. Gibson, Deepak Bhandari, Mary Ellen McNally, Ron M. Hoffman, Kelsey D. Cook, Liguo Song
Mass Spectrometry Center, Department of Chemistry, University of Tennessee, Knoxville, TN, USA and Analytical Sciences, DuPont Crop Protection, Stine Haskell Research Center, Newark, DE, USA
Batch slurry reactions are widely used in the industrial manufacturing of chemicals, pharmaceuticals, petrochemicals and polymers. However, onsite monitoring of batch slurry reactions is still not feasible in production plants due to the challenge in analyzing heterogeneous samples without complicated sample preparation procedures. In this study, direct analysis in real time mass spectrometry (DART-MS) has been evaluated for the onsite monitoring of a model batch slurry reaction. The results suggested that automation of the sampling process of DART-MS is important to achieve quantitative results. With a sampling technique of manual sample deposition on melting point capillaries followed by automatic sample introduction across the helium beam, relative standard deviation (RSD) of the protonated molecule signals from the reaction product of the model batch slurry reaction ranged from 6 to 30%. This RSD range is improved greatly over a sampling technique of manual sample deposition followed by manual sample introduction where the RSDs are up to 110%. Furthermore, with the semi-automated sampling approach, semi-quantitative analysis of slurry samples has been achieved. Better quantification is expected with a fully automated sampling approach.
Randy L. Self, Wen-Hsin Wu
U.S. Food and Drug Administration, Office of Regulatory Affairs, Applied Technology Center/Pacific Regional Laboratory Northwest, 22201 23rd DR SE, Bothell, WA 98021, USA
Food Control, Volume 25, Issue 1, May 2012, Pages 13-16A recent food safety issue involves the contamination of a broad range of food and nutraceutical products from Taiwan with industrial plasticizers. Among the suspected contaminants are selected phthalic acid esters, such as benzyl butyl phthalate, dibutyl phthalate, diisobutyl phthalate, di-2-ethylhexyl phthalate, di-n-octyl phthalate, diisononyl phthalate, and diisodecyl phthalate. Described in this study is an analytical method to rapidly qualitatively analyze these compounds in a wide variety of food and nutraceutical matrices suspected in this crisis. The method utilizes direct analysis in real time (DART) ionization coupled to a Thermo Exactive orbitrap mass spectrometer. The method is shown to be capable of detecting these compounds at levels greater than 1.0 μg/mL in all food products examined and 0.5 μg/mL in most of the samples tested. In the nutraceutical samples tested, the compounds were detected at levels of 50 μg/g for all samples with some detected as low as 1.0 μg/g.
Practical considerations for the rapid screening for pesticides using ambient pressure desorption ionisation with high-resolution mass spectrometry
S.E. Edison, L.A. Lin, and L. Parrales
US Food and Drug Administration, Forensic Chemistry Center, 6751 Steger Drive, Cincinnati, OH 45237, USA and US Food & Drug Administration, San Francisco District Laboratory, 1431 Harbor Bay Parkway, Alameda, CA 94502, USA
Food Additives & Contaminants: Part A Volume 28, Issue 10, 2011
A rapid screening method for pesticides has been developed to streamline the processing of produce entering the United States. Foam swabs were used to recover multi-class mixtures of 240, 140, 132 and 60 pesticides from the surfaces of apples, kiwis, peaches and tomatoes. The mixtures were selected to span a large range of chemical classes, polarities, solubilities and sizes to provide a broad look at how this technique will perform for a variety of analytes. The swabs were analysed using direct analysis in real-time (DART) ionisation coupled with a high-resolution Exactive Orbitrap™ mass spectrometer. This study expands the types of commodities analysed using this method and explores the feasibility of compositing multiple units of produce per batch to analyse a representative sample. It was established that whilst smooth-skinned produce, such as apples, maintained a high detection rate for the pesticide mixtures even when ten apples are swabbed with one foam disk, commodities with rougher surfaces, such as peaches, suffered a decrease in detection rate when ten peaches are swabbed with one foam disk. In order to maintain some consistency across the sample preparation process, a composite size of three units was selected. The varying topography of the commodities necessitated minor modifications to the method; for example, analysis of kiwi required that the hair on the surface be shaved prior to swabbing to achieve good recovery. Additionally, the effect of storage conditions on detection rate was analysed by spiking the surface of tomatoes at levels of 5 and 10ng/g for each pesticide, storing them under refrigeration and ambient conditions for 3 and 8 days, and then analysing the surface using this method. After 8 days of storage under both conditions more than 80% of the pesticides in the mixture were detected. Also, analysis of the multi-class mixtures was performed in both positive- and negative-ion mode and many classes were detected in both modes. Some classes, such thiocarbamates, phenylamides and organochlorine pesticides, were only observed in the positive-ion mode, whilst benzoylphenylurea pesticides were only detected in the negative-ion mode.
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