Cryogenic grinding pre-treatment improves extraction efficiency of fluoroquinolones for HPLC-MS/MS determination in animal tissue

Abstract

An efficiency extraction of fluoroquinolones in chicken muscle was achieved by pulverizing it in a freezer mill before treatment with NaOH (10mM)/MeCN (1:1). The improvement of cryogenic grinding in the extraction was demonstrated for the same piece (whole leg) of four chickens treated with enrofloxacin in equal doses. A confirmatory method based on high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) was used to analyze the extracts. The chromatographic separation was achieved in 5 min with a Synergi Fusion-RP 80A (50 x 2 mm, 4 microm) column filled with a hybrid polymer. The HPLC was coupled with a detector based in a quadrupole-linear ion trap Q-TRAP that allows a confirmatory detection according to the European legislation. The specificity of the method was assessed by testing a number of representative blank muscle samples (n = 10) to verify the absence of potential interfering compounds. The limits of detection and quantitation were 2 and 5 ng g(-1) of quinolones in muscle samples, respectively. The chromatographic method was demonstrated to be linear for the range studied (5-500 ng g(-1)) with the P value for lack-of-fit in the ANOVA table greater or equal to 0.10 (calibration coefficient 0.9998 and 0.9996 for ciprofloxacin and enrofloxacin, respectively). The mean intra-day relative standard deviation (RSD) (n = 6, c = 50 ng g(-1)) was 6%; inter-day assay gave a RSD of 12%. The extraction and clean-up were carried out in one step with very satisfactory recovery data (between 65 and 101%).

Quantitative LC–MS/MS method for the sensitive and simultaneous determination of natural hormones in bovine serum

“…Deproteinization and extraction with acetonitrile, without later steps, permits the HPLC/MS-MS analysis of fluoroquinolones [38,39] or steroids [40] and this procedure has been used in our laboratory for some years.…”

Drug mechanochemical activation

“…Among them attritors, ball mills and Pin mills can be remembered. In particular, a widely used71, 73, 74 mill is SPEX model 6750. It consists of stainless steel vessel immersed in liquid nitrogen, within which a stainless steel rod was vibrated by means of a magnetic coil.…”

Determination of naturally occurring progestogens in bovine milk as their oxime derivatives using high performance liquid chromatography-electrospray ionization-tandem mass spectrometry

“…These procedures are time‐consuming and require complicated pretreatments 2, 8, 19, 27, 28, 39. Protein precipitation with acetonitrile and subsequent recovery of the solvent, without later steps, has been successfully performed in our laboratory to extract steroids from different matrices 36, 40, 41. Moreover, the addition of ascorbic acid to standard solutions of steroids helps to protect them from oxidative processes, as it is a well‐known antioxidant.…”