Emerging N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and 6PPD quinone in paired human plasma and urine from Tianjin, China: Preliminary assessment with demographic factors.

With increasing concerns about N-(1,3-Dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and 6PPD-quinone (6PPD-Q), relevant environmental investigations and toxicological research have sprung up in recent years. However, limited information could be found for human body burden assessment. This work collected and analyzed 200 samples consisting of paired urine and plasma samples from participants (50 male and 50 female) in Tianjin, China. Low detection frequencies (DF, <15 %) were found except for urinary 6PPD-Q (86 %), which suggested the poor residue tendency of 6PPD and 6PPD-Q in blood. The low DFs also lead to no substantial association between two chemicals. Data analysis based on urinary 6PPD-Q showed a significant difference between males and females (p < 0.05). No significant correlation was found for other demographic factors (Body Mass Index (BMI), age, drinking, and smoking). The mean values of daily excretion (ng/kg bw/day) calculated using urinary 6PPD-Q for females and males were 7.381 ng/kg bw/day (female) and 3.360 ng/kg bw/day (male), and apparently female suffered higher daily exposure. Further analysis with daily excretion and ALT (alanine aminotransferase)/TSH (thyroid stimulating hormone)/ blood cell analysis indicators found a potential correlation with 6PPD-Q daily excretion and liver/immune functions. Considering this preliminary assessment, systematic research targeting the potential organs at relevant concentrations is required.

Development of a solubility parameter calculation-based method as a complementary tool to traditional techniques for indoor dust microplastic determination and risk assessment.

Herein, a method based on solubility parameter calculation was first used to analyze microplastics in indoor dust. The limit of quantification (LOQ) reached 0.2 mg/g, and the result of reference material SRM 2585 (n = 3) was 14.8 mg/g ± 1.8 %, suggesting satisfying sensitivity and precision. Recoveries of spiking experiments were > 80 % with no obvious matrix interferences observed, except ethylene propylene diene monomer (EPDM) MPs. Further, 69 indoor dust samples were analyzed to verify the method and to assess exposure scenarios for graduate students in Tianjin, China. EPDM was identified in an indoor environment for the first time as the second most widely detected type after PET in this work. The mass-based result is complementary to the outcomes from thermogravimetric analysis-gas chromatography-mass spectrometry and laser direct infrared imaging. Significant correlations were found between total organic carbon (TOC), microplastics, and BDE-209 concentrations, indicating microplastics important contaminant vectors in indoor dust. Dormitory stays and PET contributed the most to health risks among the three exposure scenarios and detected four polymers, respectively. This work provides an approach with the potential for the standardized determination of microplastics in complex environmental matrices and reveals exposure characteristics of indoor dust microplastics.

HPLC-CAD as a supplementary method for the quantification of related structure impurities for the purity assessment of organic CRMs.

In organic purity assessment, chromatography separation with a suitable detector is required. Diode array detection (DAD) has been a widely used technique for high-performance liquid chromatography (HPLC) analyses, but its application is limited to compounds with sufficient UV chromophores. Charged aerosol detector (CAD), as a mass-dependent detector, is advantageous for providing a nearly uniform response for analytes, regardless of their structures. In this study, 11 non-volatile compounds with/without UV chromophores were analyzed by CAD using continuous direct injection mode. The RSDs of CAD responses were within 17%. For saccharides and bisphenols, especially, the RSDs were lower (2.12% and 8.14%, respectively). Since bisphenols exist in UV chromophores, their HPLC-DAD responses were studied and compared with CAD responses, with CAD showing a more uniform response. Besides, the key parameters of HPLC-CAD were optimized and the developed method was verified using a Certified Reference Material (CRM, dulcitol, GBW06144). The area normalization result of dulcitol measured by HPLC-CAD was 99.89% ± 0.02% (n = 6), consistent with the certified value of 99.8% ± 0.2% (k = 2). The result of this work indicated that the HPLC-CAD method could be a good complementary tool to traditional techniques for the purity assessment of organic compounds, especially for compounds lacking UV chromophores.

A Chinese Patient with Spastic Paraplegia Type 4 with a De Novo Mutation in the SPAST Gene.

BACKGROUND: Spastic paraplegia type 4 (SPG4) is the most common type of hereditary spastic paraplegia (HSP) caused by mutations in the SPAST gene. Case Presentation. We report the case of a 27-year-old pregnant Chinese woman with HSP in whom we identified a missense mutation in the SPAST gene (c.1496G>A, p.Arg499His) and a nonsense mutation in the NEFH gene (c.289G>T, p.Glu97 ∗ ) via whole-exome sequencing; this finding corroborated that of Sanger sequencing. The patient exhibited the pure SPG4 phenotype with onset during childhood. The SPAST mutation was absent in the parents and paternal relatives. However, the NEFH mutation was identified in five people with no clinical phenotype. Based on theoretical conjecture and the family gene segregation information, we concluded that the SPAST mutation, but not the NEFH mutation, accounted for the proband's phenotype. Eventually, the woman gave birth to a healthy baby girl with the NEFH mutation. CONCLUSION: In this report, we identified a missense mutation in the SPAST gene (p.Arg499His) in a 27-year-old pregnant Chinese woman with HSP. We believe that this study expands the knowledge about the clinical parameters and mutation spectrum of SPG4.

Calculation and Experimental Validation of a Novel Approach Using Solubility Parameters as Indicators for the Extraction of Additives in Plastics.

Accurately quantifying chemical additives with adverse health effects in plastic products is critical for environmental safety and risk assessment. In this work, a novel approach using solubility parameters (δ) as indicators for the extraction of additives in plastics was developed. The mechanism was evaluated by using 10 organic solvents with different solubility parameters to extract brominated flame-retardant-decabrominated diphenyl ether (BDE-209) in polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET). Certified reference materials (CRMs) or CRM candidate materials were applied as matrix materials. The extracted BDE-209 and solubility parameters of solvents could fit into a curve of a quadratic function. The value of abscissa corresponding to the vertex of the function was close to the solubility parameter of plastic calculated by the group contribution method (Δδ < 0.37). Toluene, n-hexane, and acetone were the solvents with high extraction efficiency for PE, PP, and PET, confirming the feasibility of the developed approach. The results of ethyl acetate and acetone indicated the high weight of functional groups affecting the dissolution behavior. The developed approach was further verified by analyzing penta-/octa-BDE and phthalate esters in PET and polyvinyl chloride (PVC) and finally applied to analyze 15 plastic products made of PP, PE, PET, polystyrene, and PVC. The detected tetrabromodiphenyl ether (BDE-47), BDE-209, decabromodiphenyl ethane, and di(2-ethylhexyl) terephthalate all matched the approach and verified its practicability for field sample analysis.