Identification of “unknown analytes” in injection sites: a semi-quantitative interpretation

• Published in: Analytica chimica acta Vol. 483; no. 1; pp. 387 - 399
• Main Authors: De Wasch, K, Van Hoof, N, Poelmans, S, Okerman, L, Courtheyn, D, Ermens, A, Cornelis, M, De Brabander, H.F
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Amsterdam Elsevier B.V 25.04.2003; Elsevier
• Subjects: Analysis; Analytical chemistry; Animal productions; Biological and medical sciences; Chemistry; Chromatographic methods and physical methods associated with chromatography; Exact sciences and technology; Florfenicol; Fundamental and applied biological sciences. Psychology; General pharmacology; Liquid chromatography with mass spectrometry (LC-MS n); Maximum residue limit (MRL); Medical sciences; Other chromatographic methods; Penicillin G benzathine; Pharmacology. Drug treatments; Phenylbutazone; Spectrometric and optical methods; Terrestrial animal productions; Vertebrates; Veterinary; Phenylbutazone; Liquid chromatography with mass spectrometry (LC-MS n ); Penicillin G benzathine; Maximum residue limit (MRL); Veterinary; Florfenicol; Drug; Chemical analysis; Coupled method; Liquid chromatography; Injection site; Veterinary medicine; Residue; Animal production; Benzathine benzylpenicillin; Mass spectrometry; Liquid chromatography with mass spectrometry (LC-MSn)
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/S0003-2670(02)01031-0

The analytical approach to the detection of residues of legally used veterinary medicinal products (VMPs) is similar to the approach of forbidden substances. The only difference lies in the quantitative component of the method. Since there is an evolution towards a different strategy in the screening for VMPs in matrices of slaughtered animals, a new approach was developed for determining the residues. The aim of this research was to create an efficient screening approach for determining the identity and/or quantity of legally and illegally used VMPs present at high concentrations in injection sites. The determination of these ‘unknown’ VMPs is combined with a fast report to the customer. Examples are given of the identification of phenylbutazone, penicillin G benzathine and florfenicol. For quantitative purposes, using a mini-validation procedure, concentrations far above the maximum residue limit (MRL) of the identified VMP can be reported. A quantitative validation normally consists of determining the required validation parameters at three levels: 1/2 MRL, MRL, 2 MRL. For highly concentrated injection sites, an alternative approach is proposed. The alternative validation consists of a comparison of the analyte concentration in the sample with the spike at the MRL and 10 times the MRL concentration.