Agilent Manuals

A method for determining the residues of melamine in milk powder and egg

This article describes the analysis of flavonoids in plant extracts using CE-MS. The combination of electrospray ionization mass spectrometry (ESI-MS) with capillary electrophoresis allows for specific identification of analytes in complex matrices. The analysis of flavonoids from orange extracts is presented as an example, highlighting the specificity and sensitivity of the method. Monitoring the presence of these flavonoids in orange juice can be used to assess the quality of the product.

This document introduces the method of using capillary electrophoresis to analyze artificial sweeteners and preservatives in drinks. The method has been successfully applied to both beverages and tablet formulations.

Abstract: Synthetic food dyes were separated by capillary zone electrophoresis using an alkaline phosphate buffer as background electrolyte. The precision had a relative standard deviation of less than 0.5 % for the run-to-run migration times and 2 % for the peak areas with buffer replenishment after each run. The detection limit for the individual dyes was about 1 ng using a 50-µm internal diameter Agilent extended path length capillary. Compounds were detected at different wavelengths— 215, 410, 520 and 598 nm—and the identities of the individual dyes were confirmed using peak-purity routines and a UV-visible spectral library.

This document describes an improved chiral separation of enantiomers of linalool using a multidimensional capillary GC system with Deans switch heart-cutting and independent column temper- ature control.

The method is used for the simultaneous determination of three antibiotic residues of chloram- phenicol (CAP), florfenicol (FF), and thiamphenicol (TAP) in honey.

This application note describes the utility of phenyl columns using 100% aqueous mobile phases without the inconvenience of phase collapse. The selectivity of different Agilent ZORBAX phenyl phases (StableBond SB-Phenyl, Eclipse XDB-Phenyl and Eclipse Plus Phenyl-Hexyl) is demonstrated with both aliphatic acids and catecholamines (bases).

Determination of Sulfonamides in Milk Using Solid-Phase Extraction and Liquid Chromatography-Tandem Mass Spectrometry

This document describes the method for the detection of β-lactam antibiotics in milk. These antibiotics are widely used in veterinary medicine for the treatment and prevention of diseases. The presence of residues in milk and edible tissues can cause problems in fermentation processes and health issues for individuals hypersensitive to β-lactams. To protect consumers, maximum residue limits (MRL) were set in EU regulation 2377/90. For milk, these values range from 4 µg/kg for penicillin G, ampicillin, and amoxicillin to 30 µg/kg for dicloxacillin, cloxacillin, and oxacillin. Screening is usually performed using microbiological and immunological methods. Confirmation, however, requires an independent physicochemical technique. Therefore, a highly sensitive LC/MS/MS method was developed for the detection of penicillins in milk samples.

This document describes the use of LC/MS/MS 6410 for the analysis of chloramphenicol, thiamphenicol, and florfenicol in fish samples. The document also mentions that these compounds are banned in the EU and that LC/MS/MS is used for its greater sensitivity and higher selectivity. The method allows for the detection of all three compounds within less than 6 minutes and shows good performance in negative mode.

Sulfonamides are drugs used to treat bacterial infections, including pneumonia, meningitis, and tuberculosis. They work by inhibiting bacterial protein synthesis. Sulfonamide residues in animals may be harmful to human health. This study performed a multiresidue analysis of sulfonamide residues in pork using the Agilent 6410A LC/MS/MS. The method can simultaneously detect multiple sulfonamides and has high sensitivity, which can be used for screening, confirmation, and quantification.

A high performance liquid chromatography tandem mass spectrometric (HPLC/MS/MS) method was developed for the simultaneous determination of 10 antibiotic residues: minocycline, 4-epioxytetracycline, 4-epitetracycline, tetracycline, 4-epichlortetracycline, demeclocycline, chlortetracycline, methacycline, doxycycline, oxytetracycline in milk and animal tissues. In the method, Agilent’s novel solid phase extraction cartridge and a reversed phase Agilent ZORBAX RX C8 column (5 µm, 150 mm × 2.1 mm) were used for purification and separation. The limit of detection (LOD) is between 0.5 and 10.0 µg/kg and the limit of quantitation (LOQ) is less than 50 µg/kg. The linearity is obtained from 5 to 1000 µg/kg. Overall recoveries are between 76.4% and 101% with a relative standard deviation (RSD, n = 6) less than 8.4%. The method is rapid, sensitive, convenient and robust, and can be used to simultaneously confirm multi-residues of tetracyclines and their metabolites in milk.

Two isocratic reversed-phase methods that have distinct selectivity, and use popular UV/MS or UV detection, are presented for analyzing Rebaudioside A and other steviol glycosides. A Rapid Resolution High Throughput (RRHT) Eclipse Plus Phenyl-Hexyl method using UV and MS detection resolved many compounds from a Stevia rebaudi- ana Bertoni plant extract instead of the other approach employing an amino column with a refractive index (RI) or other special detector. The RRHT Eclipse Plus Phenyl- Hexyl method’s advantages include high peak capacity, isocratic mobile phase, low acetonitrile consumption, and unique selectivity compared to a ZORBAX Carbohydrate Analysis column method. Three commercially available Stevia sweeteners were ana- lyzed for Rebaudioside A and Stevioside, the two major diterpenoid glycosides present in stevia leaves.