The Application Notebook-09-02-2007

The Application Notebook

Improved LC–MS Performance — A Three-Step Method for Minimizing Background Signals and Increasing Ionization Efficiency

September 02, 2007

General

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One problem frequently encountered in LC–MS is the appearance of mass peaks, which appear totally unrelated to the samples run - "ghost" mass peaks. It is impossible to differentiate whether these signals come from an unknown component in the sample co-eluting with a known peak, or from an impurity in the mobile phase or from some residual contamination "bleeding" from the column.

Direct Injection of Fish Oil for the GC–ECD Analysis of PCBs: Results Using a Deans Switch with Backflushing

September 02, 2007

Food and Beverage

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A Deans switch, employing Agilent's Capillary Flow Technology, was configured on an Agilent 7890A GC equipped with dual ECD detectors. A method was developed for the analysis of fish oil for PCB contamination. The Deans switch was used to heart cut 7 indicator PCBs (IUPAC Numbers 28, 52, 101, 118, 138, 153 and 180) from the primary DB-XLB column on to a DB-200 column for further separation. Fish oil from a supplement capsule was simply diluted 1:10 in isooctane and injected directly. To prevent carryover, contamination and retention time shifts, the Deans switch was used to backflush the primary column at the end of each run.

Analysis of Biodiesels Using LC–MS

September 02, 2007

General

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Preliminary studies of biodiesel samples by a high speed LC–MS system using electrospray ionization and a patented cone-wash feature demonstrate that LC–MS reduces the analysis time to 20 minutes and reveals information about higher molecular weight compounds in biodiesel while still detecting many low molecular weight chemicals, including FAMEs, at high sensitivity.

Biodiesel Analyser Determines the Quality of Fatty Acid Methyl Esters (FAME) Blending Stock for Diesel Fuel

September 02, 2007

Environmental

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AC Analytical Controls developed a new chromatographic solution that complies with all ASTM & EN chromatographic test methods listed in biodiesel specifications: the AC all-in-one Biodiesel analyser. Analysis results demonstrate that the AC analyser complies with EN 14103, EN 14105, EN 14106, EN 14110 & ASTM D6584 methods.