The surface of superparamagnetic magnetic beads was modified with bisphosphonates to selectively capture calcium phosphate crystals from complex biological fluids (i.e. synovial fluid).

The development of antibiotic resistance in bacteria has been attributed to the overuse of antimicrobials in human medicine. Another route by which humans are exposed to antibiotics is through the animal foods we eat. In modern agricultural practice, veterinary drugs are being used on a large scale, administered for treating infection or prophylactically to prevent infection. Hence, there is pressure on analytical scientists to detect and confirm the presence of antimicrobials in foods of animal origin.The aminoglycosides and macrolides are two families of antibiotics, each with important applications in veterinary medicine. These antibiotics are widely used in the treatment of bacterial disease, e.g., aminoglycosides for mastitis and macrolides for enteric infections. They have also been used as feed additives for growth promotion. As a result, legislation has been laid down by the European commission in which member states must meet strict criteria for monitoring residues (including antimicrobials). Testing for low levels of aminoglycosides and macrolides in foods is a priority and hence the development of fast, reliable, sensitive methods for their extraction and subsequent analysis is of great interest.This paper reviews analytical methods for both extracting and determining these classes of antibiotics in various food matrices focusing in particular on the last 10 years. Extraction and clean-up methods such as deproteinisation, and solid-phase extraction are described. Various screening methods are also covered including thin layer chromatography (TLC), enzyme immunoassay, capillary electrophoresis (CE) and microbiological assays. Finally, liquid chromatography (LC) methods are discussed which are combined with mass spectrometry (MS) when sensitivity requirements are stringent.

Clinically, osteoarthritis (OA) is characterised by joint pain, stiffness after immobility, limitation of movement and, in many cases, the presence of basic calcium phosphate (BCP) crystals in the joint fluid. The detection of BCP crystals in the synovial fluid of patients with OA is fraught with challenges due to the submicroscopic size of BCP, the complex nature of the matrix in which they are found and the fact that other crystals can co-exist with them in cases of mixed pathology. Routine analysis of joint crystals still relies almost exclusively on the use of optical microscopy, which has limited applicability for BCP crystal identification due to limited resolution and the inherent subjectivity of the technique. The purpose of this Critical Review is to present an overview of some of the main analytical tools employed in the detection of BCP to date and the potential of emerging technologies such as atomic force microscopy (AFM) and Raman microspectroscopy for this purpose.

A series of derivatisation reactions between p-t-butyl calix[4]arene and ethyl bromoacetate were carried out in order to prepare 1,3 diester substituted calix[4]arene. Mass spectral data, obtained from direct injection of samples, indicated that the reactions were rich in the desired product. Since the ultra violet (UV) spectra of the desired product and possible impurities are very similar, liquid chromatography (LC) chromatographic data seemed to corroborate these results. However, when on-line LC-UV-MS was carried out and each LC peak subjected to MS analysis as it eluted, a very different picture emerged. It was found that many of these reactions actually contained high levels of the monoester product which, having less affinity for sodium in the MS, is therefore seriously underestimated in any direct injection assay. LC-diode array detection (DAD) methods were also used to help successfully identify and characterise the compounds being formed in these complex reactions. The overall results obtained in this paper allowed the optimal reaction conditions to be determined for this reaction. LC-MS analysis of the chromatographic peaks also identified the presence of two isomers of the diester substituted calix[4]arene (1,3 and 1,2 diesters). The combination of LC and UV/MS detection is required for accurate analysis of the products of such reactions.

The surface of superparamagnetic magnetic beads was modified with bisphosphonates to selectively capture calcium phosphate crystals from complex biological fluids (i.e. synovial fluid).