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A novel portable smartphone-assisted colorimetric method was reported for the determination of Hg2+ with good analytical performance. A Zr(IV)-based metal–organic framework functionalized with amino groups (NH2-UiO-66) has been adopted as a supporting platform to anchor gold nanoparticles (AuNPs), avoiding the migration and aggregation of AuNPs. With the addition of Hg2+, the formation of gold amalgam proved possible to enhance peroxidase-like activity of the composite (AuNPs/NH2-UiO-66), accelerating the oxidization of zymolyte 3,3′,5,5′-tetramethylbenzidine (TMB). In the meantime, the color of the reaction solution turned a vivid blue, and the red, green, and blue (RGB) values of the solution color changed accordingly. On account of this strategy, the quantitative detection of Hg2+ could be achieved. After the optimization of the experiment conditions, the average color intensity (Ic) resulting from RGB values was linear related to the concentration of Hg2+ from 10 to 100 nM, accompanied with a detection limit (LOD) down to 5.4 nM calculated by 3σ/S. The successful application of the designed method has been promoted to detect Hg2+ in some water samples, displaying a great potential in practical application. Furthermore, the use of a smartphone made our proposed method simple and accurate, and thus puts forward a possible way for in situ and real-time monitoring. A portable smartphone-assisted RGB colorimetric method for Hg2+ detection based on Hg2+-enhanced peroxidase-like activity of AuNPs modified on NH2-UiO-66. [ABSTRACT FROM AUTHOR]

Mass spectrometry (MS) is the most reliable and accurate method for measuring polychlorodibenzo-p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs). High-resolution gas chromatography coupled with high-resolution mass spectrometry (referred to as magnetic double-focusing mass spectrometry) has been recommended as the 'gold standard' for the determination of PCDD/Fs in various samples. Many techniques and instruments, such as triple quadrupole MS (QqQ-MS), time-of-flight MS (TOF-MS), ion trap MS (IT-MS), Fourier-transform ion cyclotron resonance MS (FTICR-MS), and orbitrap MS, have been employed for the determination of PCDD/Fs. In this review, the progress in MS-related techniques used for PCDD/F determination in different matrices is updated. The sensitivity, recovery, and precision of these methods are summarized. The potential applications and unique merits of MS as a novel technique for the determination of PCDD/Fs are discussed. [ABSTRACT FROM AUTHOR]

Phthalates (PAEs) are a class of endocrine-disrupting chemicals. In recent years, the harmful effects of PAEs on human health, in particular their toxicity toward the reproductive system and development, have received significant attention because of their increasing production and usage. PAEs are ubiquitous in the environment and food products, resulting in unavoidable and long-term exposure in humans. Therefore, exposure and risk assessments of PAEs in humans are necessary. Screening and quantification of phthalate metabolites in urine is an important method for evaluating PAEs exposure, and establishing accurate analytical methods for this purpose has become a high priority. Phthalate monoesters and secondary metabolites are the most commonly targeted biomarkers of exposure to short-and long-chain PAEs, respectively. The combination of off-line or on-line solid phase extraction (SPE) with high performance liquid chromatography-tandem mass spectrometry has become the preferred method for the determination of phthalate metabolites. This paper reviews the analytical methods available for the detection of urinary phthalate metabolites and discusses the advantages, limitations, and challenges presented by each method in practical applications.