Determination of Semicarbazide in Fresh Egg and Whole Egg Powder by Liquid Chromatography/Tandem Mass Spectrometry: Interlaboratory Validation Study

An interlaboratory validation study was conducted according to harmonized protocols to evaluate the effectiveness of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of semicarbazide (SEM) in fresh whole egg and in an industrially processed whole egg powder. The sample was extracted with hydrochloric acid and derivatized with 2-nitrobenzaldehyde, with 1,2-[15N213C]SEM as the internal standard. The extract was neutralized and purified on a solid-phase extraction cartridge. SEM was determined by reversed-phase LC with detection by MS/MS. Five fresh egg samples, of which 3 were obtained from hens fed nitrofurazone (NFZ), one was spiked with SEM at 50 μg/kg and one was a blank sample, and 5 industrial whole egg powder samples, of which 3 were spiked with fresh whole egg from hens fed NFZ, one was spiked with SEM at 350 μg/kg, and one was a blank sample, were sent to 15 laboratories in 10 different European countries. Results were obtained from 12 participants. Average recoveries of SEM from the fresh egg and the egg powder samples were 105.3 and 121.3%, respectively. The relative standard deviation for repeatability (RSDr) ranged from 2.9 to 9.3%, and the relative standard deviation for reproducibility (RSDR) ranged from 22.5 to 38.1%. The method showed acceptable within- and between-laboratory precision for both matrixes, as evidenced by the HorRat values, at the target levels for the determination of SEM.

Determination of Semicarbazide in Baby Food by Liquid Chromatography/Tandem Mass Spectrometry: Interlaboratory Validation Study

An interlaboratory validation study funded by the European Commission, Directorate General for Health and Consumer Protection (DG SANCO), was conducted to evaluate the effectiveness of a liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the determination of semicarbazide (SEM) in different types of baby food at a possible future European regulatory limit (10 ng/g). The test portion of the sample was extracted with hydrochloric acid, and the analyte was derivatized with 2-nitrobenzaldehyde, with 1,2-[15N2, 13C] SEM as an internal standard. The extract was neutralized and then purified on a solid-phase extraction cartridge. The SEM was determined by reversed-phase LC with detection by MS/MS. Apple puree, rice pudding, and meat/vegetable meal baby food materials, spiked with SEM at levels of about 3, 10, and 30 ng/g, respectively, were sent to 20 laboratories in 12 different European countries, which submitted results from 17 participants. Recoveries ranged from 88.8 to 106.1%. Based on results for spiked samples (blind pairs at 3 levels), the relative standard deviations for repeatability (RSDr) ranged from 4.2 to 6.9% and the relative standard deviations for reproducibility (RSDR) ranged from 16.6 to 24.3%. The method showed acceptable within- and between-laboratory precision for all 3 matrixes, as evidenced by HorRat values, at the target levels for the determination of SEM.

Formation of semicarbazide (SEM) in food by hypochlorite treatment: is SEM a specific marker for nitrofurazone abuse?

Semicarbazide (SEM) is considered to be a characteristic protein-bound side-chain metabolite of the banned veterinary drug nitrofurazone. It is therefore used as a marker for nitrofurazone abuse. Recently, there has been concern about other sources of SEM in tissue samples, which are not linked to the illegal use of nitrofurazone. The present studies have shown that SEM can occur naturally, e.g. in algae, shrimps and eggs, and is formed from natural substances, e.g. arginine and creatine. A significant formation of SEM was observed in samples treated with hypochlorite commonly used in food processing for disinfection or bleaching. SEM was formed in different kinds of nitrogen compound-containing samples (0.3-20 microg kg(-1)) after treatment with 1% active chlorine. It was detected in the mg kg(-1) range after hypochlorite treatment (0.015% active chlorine) of creatine. Lower levels were also formed from creatinine, arginine and urea. SEM present in hypochlorite-treated carrageenan proved mostly to occur in the tissue-bound form. Therefore, differentiation between SEM from nitrofurazone abuse and SEM originating from natural constituents (due to hypochlorite treatment) seems not to be unambiguously possible.