Barium Sulfate Nanoparticles as a Coating for Solid-Phase Microextraction of Polycyclic Aromatic Hydrocarbons in Aqueous Samples

In-vial solid-phase extraction of polycyclic aromatic hydrocarbons in drug formulations stored in packaging containing rubber

Polycyclic aromatic hydrocarbons (PAHs) are a class of ubiquitous and persistent organic compounds that are significantly teratogenic, carcinogenic and mutagenic. Rubber stoppers commonly used in sterile formulation packaging materials often contain carbon black as the additive to enhance mechanical strength. However, PAHs may be formed during the production of carbon black, which could cause the drug formulations to be contaminated when contacting with the rubber stopper, and then enter the patient's body. The determination of PAHs in drug formulations is challenging, due to their trace amounts and matrix interference. Therefore, sample pretreatment is necessary and important. In this work, a novel technique, named in-vial solid-phase extraction (IVSPE), was developed for the selective extraction and enrichment of 16 PAHs in pharmaceuticals. The coated sample vial was directly used as the container for the whole process of sample pretreatment. As the solid-phase adsorbent, the coating was prepared by successively modifying the inner surface of a sample vial with polydopamine film and octadecylamine. PAHs could be selectively extracted through π-π stacking interaction and hydrophobic interaction, and then desorbed and enriched by a small amount of organic solvent. After systematic optimization of the coating preparation and the extraction process, the limits of detection and quantification of 16 PAHs were in the range of 0.002-0.60 ng mL^-1 and 0.007-2.00 ng mL^-1, respectively. Good linearities and precision of six repeated injections were obtained. The recoveries at three spiked concentration levels in normal saline were in the range of 62.72-106.90% with the relative standard deviation between 0.83% and 6.78%. Finally, PAHs in normal saline and powders for injection were extracted by established IVSPE, followed by separation and detection with high-performance liquid chromatography with a fluorescence detector and diode array detector (HPLC-FLD/DAD). It is worth noting that the preparation conditions of the adsorbent in the IVSPE method are mild, simple and green. Moreover, IVSPE has the advantages of having few work steps and avoiding the risk of contamination, because no special instrumentation or sample transfer is required. IVSPE could also be used for the pretreatment of multiple samples at the same time, which is beneficial to practical applications.

Analytical methods to analyze pesticides and herbicides

Presented in this paper is an annual review of literatures published in 2018 on topics relating to analytical methods for pesticides and herbicides. According to the different techniques, this review is divided into six sections, including extraction methods; chromatographic or mass spectrometric techniques; electrochemical techniques; spectrophotometric techniques; chemiluminescence and fluorescence methods; and biochemical assays. PRACTITIONER POINTS: Totally 134 relevant research articles are summarized. The review is divided into six parts according to the techniques. Chromatographic and mass spectrometric methods are the most widely used.

Electroless deposition of silver nanofractals on copper wire by galvanic displacement as a simple technique for preparation of porous solid-phase microextraction fibers

A novel and porous solid-phase microextraction fiber was prepared by quick and simple galvanic displacement reaction and applied to the determination of some polycyclic aromatic hydrocarbons in sunflower oil. The parameters affecting the porosity and thickness of the fiber, and parameters affecting the extraction efficiency, including the extraction time, temperature, and ionic strength, were investigated and optimized. The morphology of prepared fiber was characterized by optical and scanning electron microscopy and thermal and chemical stabilities of the fiber were studied. Under the optimum conditions, the limits of detection ranged between 0.1 ng/mL for pyrene to 1.2 ng/mL for anthracene, and LOQ ranged between 0.3 ng/mL for pyrene to 3.6 ng/mL for anthracene. The relative standard deviations, including repeatability (within fibers) and reproducibility (between fibers), varied between 3.2-8.9 and 5.6-9.8%, respectively.