Quantitative analysis of iron-containing protein myoglobin in different foodstuffs by liquid chromatography coupled to high-resolution inductively coupled plasma mass spectrometry.
Quantitative determination was made of the iron-containing protein myoglobin in a range of different foods, including meat, processed meat, fish, and shellfish, by liquid chromatography coupled to a double-focusing sector field inductively coupled plasma mass spectrometry (ICP-MS). The concentration of myoglobin determined in the samples ranged from 0 to 6.5 mg/kg, and the analytical precision (coefficient of variation) for the analysis of 8 replicate raw steak extracts was 2.1%. By using a double-focusing ICP-MS instrument, direct on-line detection of the most abundant iron isotope 56Fe was possible without interference from a major polyatomic interference (40Ar16O). Separation of myoglobin from other iron-containing compounds was facilitated by use of a gel filtration column (TSK Gel G2000SW) and Tris buffer (pH 7.2). The chromatographic column was coupled directly to the nebulizer of the ICP-MS instrument by a short piece of PEEK tubing. To ensure sufficient quality control throughout the study, a raw beefsteak sample was developed as an in-house reference material. The concentration of the heme-iron-containing protein myoglobin in this sample was determined by the developed method and independently by a conventional spectrophotometric method. The agreement between the 2 analytical techniques was very good. The detection limit (3 times the signal/noise ratio for a blank) of the reported method for myoglobin was 0.85 ng Fe/L.
Harrington
Chris F
CF
LGC (Teddington) Ltd., Queens Rd, Teddington, Middlesex, TW11 0LY, United Kingdom. cfh7@leicester.ac.uk
Elahi
Selvarani
S
Merson
Sheila A
SA
Ponnampalavanar
Punitha
P
D000818:Animals; D002138:Calibration; D002417:Cattle; D002853:Chromatography, Liquid; D005399:Fishes; D005504:Food Analysis; D007202:Indicators and Reagents; D007501:Iron / Q000032:analysis*; D013058:Mass Spectrometry; D008460:Meat / Q000032:analysis; D009211:Myoglobin / Q000032:analysis*; D019159:Nonheme Iron Proteins / Q000032:analysis; D011786:Quality Control; D012015:Reference Standards; D012756:Sheep; D012758:Shellfish / Q000032:analysis
D007202:Indicators and Reagents; D009211:Myoglobin; D019159:Nonheme Iron Proteins; D007501:Iron