Sample preparation of target compounds from biological, pharmaceutical, environmental, and food matrices is one of the most time-consuming steps in analytical procedures. Extraction techniques are dominant, especially those based on the processes running on the phase such as liquid-liquid and/or liquid-solid. Due to the reproducibility of data, precision, relatively low cost of the appropriate analysis, simplicity of the determination, and the possibility of direct combination of those techniques with other methods (both on-line and off-line), they have become the most widespread in routine determinations. Additionally, sample pretreatment procedures have to be more selective, cheap, quick, and environmentally friendly. Selectivity is obtained by using procedures based on immunoaffinity or molecular imprinting. Reduction of costs can be obtained by automation of the extraction procedures (automated SPE) or techniques like column-switching. Reducing at least the time for sample preparation is achieved by introducing miniaturization techniques (multi-well SPE). This review summarizes the current achievements and application of solid phase extraction (SPE). The main aim is to deal with the utilization of different types of sorbents for solid-phase extraction and emphasize the use of new synthesized sorbents as well as to bring together studies on a systematic approach to SPE method development.
1 February 2018 in Journal of Microbiology, Immunology and Infection
In this study, an acidophilic actinobacteria strain was used as a novel reducing agent for a single-step synthesis of nanostructure silver particles. We used a Streptacidiphilus durhamensis HGG16n isolate for efficient synthesis of bioactive silver nanoparticles [bio(AgNPs)] in an inexpensive, eco-friendly, and nontoxic manner. The obtained bio(AgNPs) exhibited unique physicochemical and biochemical properties. Structural, morphological, and optical properties of the synthesized biocolloids were characterized by spectroscopy, dynamic light scattering, and electron microscopy approaches. The antimicrobial activity was evaluated using the well- and disc-diffusion methods. The obtained crystalline structure and stable biosynthesized silver nanoparticles ranged in size from 8 nm to 48 nm and were mostly spherical in shape. Antimicrobial assays of the silver nanoparticles against pathogenic bacteria showed the highest antimicrobial activity against Pseudomonas aeruginosa, Staphylococcus aureus, and Proteus mirabilis, followed by Escherichia coli, Klebsiella pneumoniae, and Bacillus subtilis. Moreover, the synergistic effect of bio(AgNPs) with various commercially available antibiotics was also evaluated. These results provide insight into the development of new antimicrobial agents along with synergistic enhancement of the antibacterial mechanism against clinical bacteria.
Antibiotics were initially natural substances. However, nowadays, they also include synthetic drugs, which show their activity against bacteria, killing or inhibiting their growth and division. Thanks to these properties, many antibiotics have quickly found practical application in the fight against infectious diseases such as tuberculosis, syphilis, gastrointestinal infections, pneumonia, bronchitis, meningitis and septicemia. Antibiotic resistance is currently a detrimental problem; therefore, in addition to the improvement of antibiotic therapy, attention should also be paid to active metabolites in the body, which may play an important role in exacerbating the existing problem. Taking into account the clinical, cognitive and diagnostic purposes of drug monitoring, it is important to select an appropriate analytical method that meets all the requirements. The detection and identification of the microorganism responsible for the infection is also an essential factor in the implementation of appropriate antibiotic therapy. In recent years, clinical microbiology laboratories have experienced revolutionary changes in the way microorganisms are identified. The MALDI-TOF MS technique may be interesting, especially in some areas where a quick analysis is required, as is the case with clinical microbiology. This method is not targeted, which means that no prior knowledge of the infectious agent is required, since identification is based on a database match.