Environmental Exposures and Pediatric Cardiology: A Scientific Statement From the American Heart Association.

Environmental toxicants and pollutants are causes of adverse health consequences, including well-established associations between environmental exposures and cardiovascular diseases. Environmental degradation is widely prevalent and has a long latency period between exposure and health outcome, potentially placing a large number of individuals at risk of these health consequences. Emerging evidence suggests that environmental exposures in early life may be key risk factors for cardiovascular conditions across the life span. Children are a particularly sensitive population for the detrimental effects of environmental toxicants and pollutants given the long-term cumulative effects of early-life exposures on health outcomes, including congenital heart disease, acquired cardiac diseases, and accumulation of cardiovascular disease risk factors. This scientific statement highlights representative examples for each of these cardiovascular disease subtypes and their determinants, focusing specifically on the associations between climate change and congenital heart disease, airborne particulate matter and Kawasaki disease, blood lead levels and blood pressure, and endocrine-disrupting chemicals with cardiometabolic risk factors. Because children are particularly dependent on their caregivers to address their health concerns, this scientific statement highlights the need for clinicians, research scientists, and policymakers to focus more on the linkages of environmental exposures with cardiovascular conditions in children and adolescents.

Heavy Metal Exposure and Cardiovascular Disease.

Heavy metals are harmful environmental pollutants that have attracted widespread attention due to their health hazards to human cardiovascular disease. Heavy metals, including lead, cadmium, mercury, arsenic, and chromium, are found in various sources such as air, water, soil, food, and industrial products. Recent research strongly suggests a connection between cardiovascular disease and exposure to toxic heavy metals. Epidemiological, basic, and clinical studies have revealed that heavy metals can promote the production of reactive oxygen species, which can then exacerbate reactive oxygen species generation and induce inflammation, resulting in endothelial dysfunction, lipid metabolism distribution, disruption of ion homeostasis, and epigenetic changes. Over time, heavy metal exposure eventually results in an increased risk of hypertension, arrhythmia, and atherosclerosis. Strengthening public health prevention and the application of chelation or antioxidants, such as vitamins and beta-carotene, along with minerals, such as selenium and zinc, can diminish the burden of cardiovascular disease attributable to metal exposure.

Personal Strategies to Reduce the Cardiovascular Impacts of Environmental Exposures.

Ubiquitous environmental exposures increase cardiovascular disease risk via diverse mechanisms. This review examines personal strategies to minimize this risk. With regard to fine particulate air pollution exposure, evidence exists to recommend the use of portable air cleaners and avoidance of outdoor activity during periods of poor air quality. Other evidence may support physical activity, dietary modification, omega-3 fatty acid supplementation, and indoor and in-vehicle air conditioning as viable strategies to minimize adverse health effects. There is currently insufficient data to recommend specific personal approaches to reduce the adverse cardiovascular effects of noise pollution. Public health advisories for periods of extreme heat or cold should be observed, with limited evidence supporting a warm ambient home temperature and physical activity as strategies to limit the cardiovascular harms of temperature extremes. Perfluoroalkyl and polyfluoroalkyl substance exposure can be reduced by avoiding contact with perfluoroalkyl and polyfluoroalkyl substance-containing materials; blood or plasma donation and cholestyramine may reduce total body stores of perfluoroalkyl and polyfluoroalkyl substances. However, the cardiovascular impact of these interventions has not been examined. Limited utilization of pesticides and safe handling during use should be encouraged. Finally, vasculotoxic metal exposure can be decreased by using portable air cleaners, home water filtration, and awareness of potential contaminants in ground spices. Chelation therapy reduces physiological stores of vasculotoxic metals and may be effective for the secondary prevention of cardiovascular disease.

Risk assessment of heavy metals in tuna from Japanese restaurants in the Republic of Korea.

Background: Studies on the risk of mercury (Hg) in Korean fishery products focus primarily on total Hg levels as opposed to methylmercury (MeHg) levels. None of the few studies on MeHg in tuna investigated tuna from Japanese restaurants. Few have evaluated lead (Pb), cadmium (Cd) and arsenic (As) in tuna. Thus, this study aimed to conduct a risk assessment by evaluating heavy metal concentrations in tuna from Japanese restaurants. Methods: Thirty-one tuna samples were collected from Japanese restaurants in the Republic of Korea. They were classified according to region and species. The concentration of heavy metals in the samples was analyzed using the Ministry of Food and Drug Safety Food Code method. The rate of exceedance of maximum residue levels (MRLs) and the risk compared to the provisional tolerable weekly intake (PTWI) set by the Joint Food and Agriculture Organization/World Health Organization Expert Committee on Food Additives (%PTWI) were evaluated for risk assessment. Results: The mean of MeHg, Pb, Cd and As concentrations were 0.56 ± 1.47 mg/kg, 33.95 ± 3.74 µg/kg, 14.25 ± 2.19 µg/kg and 1.46 ± 1.89 mg/kg, respectively. No sample exceeded the MRLs of Pb and Cd, but 9.7% of the samples exceeded the MRL of MeHg. The %PTWIs of MeHg, Pb, Cd and As were 4.2037, 0.0162, 0.0244 and 1.1627, respectively. The %PTWI of MeHg by age group and sex was highest among men aged 19-29 years (10.6494), followed by men aged 30-49 years (7.2458) and women aged 19-29 years (4.8307). Conclusions: We found that 3 out of 31 samples exceeded the MRL of MeHg. The %PTWI of MeHg showed significant differences based on age and sex, and the value was likely to exceed a safe level depending on individuals' eating behaviors. Therefore, improved risk management for MeHg is required.

Gestational lead exposure and its effects on fetal/infant development - A systematic review.

Studies suggest that gestational exposure to lead (Pb) is related to spontaneous abortions, preterm birth, lower infant birth weight and length, and neurological dysfunctions. However, the evidence about its effects during pregnancy exposure on fetal and child development is still poor. Thus, the aim of this systematic review was to verify the association between prenatal exposure to Pb and the occurrence of neurobehavioral deficits, miscarriages, and child mortality. Observational studies with pregnant women exposed to Pb during pregnancy were included, without gender or ethnicity restrictions. The MEDLINE, Cochrane Library, EMBASE, Scopus, Web of Science, and LILACS databases were searched. The reading of titles and abstracts was conducted, followed by reading in full format and data extraction, that were performed independently by two reviewers. The included studies were evaluated by Downs and Black tool and qualitatively synthesized. Certainty of evidence was assessed by Grading of Recommendations Assessment, Development, and Evaluations (GRADE). The study protocol was registered with the Prospective Registry of Systematic Reviews (PROSPERO; CRD42022296750). Among twenty-one studies included, sixteen were classified as prospective cohort, two case-control, one nested case-control, one cohort, and one longitudinal study. No study that evaluated child mortality associated with gestational Pb exposure was found. There is a very low certainty of evidence in the association of gestational Pb exposure and neurobehavioral deficits or miscarriages. This systematic review reflects the poor evidence and the challenges of human toxicology studies, since it was not possible to associate gestational Pb exposure to neurobehavioral deficits, miscarriages, and child mortality.

Urinary concentrations of metals before and after volcanic eruption: a natural experiment surrounding the eruption of Volcán de Fuego, 2018.

Volcanic eruptions increase environmental heavy metal concentrations, yet little research has been performed on their extrapulmonary human health effects. We fortuitously collected biological samples in a cohort of Guatemalan sugarcane cutters in the area surrounding Volcán de Fuego before and after the June 2018 eruption. We sought to determine whether stratovolcanic activity was associated with changes in urinary concentrations of heavy metals in a cohort of sugarcane workers. In this exploratory analysis, we found significant increases in urinary arsenic, (ß = 1.46, P < 0.0001), cadmium (ß = 1.03, P < 0.0001), and lead (ß = 0.87, P = 0.003) in participants with residential proximity to Volcán de Fuego as compared to participants farther away, suggesting that volcanic activity could be associated with acute heavy metal exposures. This natural experiment is, to our knowledge, the first of its kind and suggests a need for more research into heavy metal exposure-related health impacts of volcanic eruptions.

Spatial distribution and health risk assessment of heavy metals in drinking water of rural schools in Henan Province / 中国学校卫生

Objective@#To evaluate health risks of five heavy metals in drinking water of rural schools in Henan Province, so as to provide scientific basis for drinking water safety in rural schools.@*Methods@#Totally 1 269 drinking water samples were collected and analyzed for five heavy metals (As, Cd, Cr 6+ , Pb, Hg) concentration in 106 cities and counties of Henan Province, and its spatial distribution characteristics were explored by geographic information system (GIS). Risk assessment method recommended by the United States Environmental Protection Agency (U.S. EPA) was applied to evaluate health risks from five heavy metals through oral ingestion.@*Results@#The qualified rate of As concentration was 100%, and the qualified rates of Cd, Cr 6+ , Pb and Hg were 99.9% , 99.9%, 99.5%, 99.6%. The highest carcinogenic risk was As (3.05×10 -5 ), followed by Cr 6+ (2.73×10 -5 ), and the highest non carcinogenic risk was As (0.158 3), followed by Pb(0.041 7). The carcinogenic risk and non carcinogenic risk were all higher in girls than boys. The carcinogenic and non carcinogenic risks were differences in different regions( P <0.05).@*Conclusion@#Health risks of five heavy metals in drinking water for rural schools in Henan Province were within the acceptable risk level recommended by EPA. As, Cr 6+ and Pb were the main health risk factors in drinking water, and that might impact negatively the healthy growth of primary and middle school students. These should be future efforts of drinking water safety management.

Estudio de metales urinarios y plomo en sangre: parámetros poblacionales en Antofagasta, 2018 / Urinary heavy metals and blood lead levels among residents of Antofagasta, Chile

Background: The presence of toxic metals in human populations is strongly associated with chronic diseases. Aim: To determine levels of lead, chromium, cadmium, mercury and inorganic arsenic (AsIn) in the general population aged over 5 years in Antofagasta, Chile. Material and Methods: People living in Urban Antofagasta for at least five years were considered eligible. Biological samples were obtained to measure heavy metals. Results: One thousand two hundred three participants with a median age of 43 years (656 women) were studied. Their mean time of residence in the city was 30 years, and 52% smoked. Eight percent of the adult population and 12% of children had AsIn values above 35 µg/L, while 75% of the population had levels below 21.9 µg/L. The other metals were below the risk levels defined by the health authority (10 µg/L for chromium, 10 µg/L for mercury, 2 µg/L for cadmium, 5 and 10 μg/dL for blood lead for children and adults, respectively). The factors associated with high levels of AsIn in adults were male sex, living more than 200 meters from monitoring points, and low schooling. In children, the associated variables were high intake of seafood products and having a caregiver with less than 8 years of schooling. Contrary to expectations, the greatest risk of presenting altered levels of the metals occurred in the population living more than 500 meters from the identified risk sources (90% of the population). Conclusions: The findings of this study suggest that all potential sources of exposure to AsIn should be evaluated, and surveillance actions should be established to reduce involuntary exposure to this metalloid.

Simultaneous voltammetric detection of cadmium(II), arsenic(III), and selenium(IV) using gold nanostar-modified screen-printed carbon electrodes and modified Britton-Robinson buffer.

The present work reports a newly developed square wave anodic stripping voltammetry (SWASV) methodology using novel gold nanostar-modified screen-printed carbon electrodes (AuNS/SPCE) and modified Britton-Robinson buffer (mBRB) for simultaneous detection of trace cadmium(II), arsenic(III), and selenium(IV). During individual and simultaneous detection, Cd2+, As3+, and Se4+ exhibited well-separated SWASV peaks at approximately - 0.48, - 0.09, and 0.65 V, respectively (versus Ag/AgCl reference electrode), which enabled a highly selective detection of the three analytes. Electrochemical impedance spectrum tests showed a significant decrease in charge transfer resistance with the AuNS/SPCE (0.8 kΩ) compared with bare SPCE (2.4 kΩ). Cyclic voltammetry experiments showed a significant increase in electroactive surface area with electrode modification. The low charge transfer resistance and high electroactive surface area contributed to the high sensitivity for Cd2+ (0.0767 µA (0.225 µg L-1)-1), As3+ (0.2213 µA (µg L-1)-1), and Se4+ (µA (µg L-1)-1). The three analytes had linear stripping responses over the concentration range of 0 to 100 µg L-1, with the obtained LoD for Cd2+, As3+, and Se4+ of 1.6, 0.8, and 1.6 µg L-1, respectively. In comparison with individual detection, the simultaneous detection of As3+ and Se4+ showed peak height reductions of 40.8% and 42.7%, respectively. This result was associated with the possible formation of electrochemically inactive arsenic triselenide (As2Se3) during the preconcentration step. Surface water analysis resulted in average percent recoveries of 109% for Cd2+, 93% for As3+, and 92% for Se4+, indicating the proposed method is accurate and reliable for the simultaneous detection of Cd2+, As3+, and Se4+ in real water samples. Graphical abstract.

Tolerancia al plomo de aislamientos nativos de Pseudomonas spp. de aguas residuales del Valle de Aburrá / Tolerance lead of native pseudomonas spp. wastewater from Aburrá Valley

RESUMEN El plomo (Pb) es un metal pesado cuyas características físico-químicas lo convierten en un contaminante ambiental persistente, bioacumulable y de alta toxicidad. La biorremediación surge como una alternativa con múltiples ventajas en comparación con los tratamientos convencionales para remover contaminantes como metales pesados de aguas residuales, basándose en las capacidades de tolerancia y mecanismos de resistencia de los microorganismos. Con el fin de conocer la tolerancia de Pseudomonas spp. al plomo presente en aguas contaminadas, se obtuvieron cuatro aislados nativos, procedentes de aguas residuales colectadas en el río del Valle de Aburrá (zona norte), los cuales se caracterizaron bioquímicamente. Se realizaron bioensayos de tolerancia en diferentes concentraciones de plomo por difusión en agar, como prueba tamiz, y determinación de la concentración mínima inhibitoria, determinando la viabilidad del microorganismo en cada exposición. No se presentó diferencia significativa para la tolerancia al plomo entre los aislados, identificados bioquímicamente como Pseudomonas aeruginosa, ni entre las diferentes concentraciones de plomo a las cuales fueron expuestos los aislados. A partir de estos resultados, se discute a cerca de los mecanismos reportados por diferentes autores, mediante los cuales Pseudomonas spp. puede actuar en presencia de Plomo. De esta manera, se concluye que los aislados de Pseudomonas spp. presentan mecanismos de tolerancia y/o resistencia hasta concentraciones de 2500 mg/L en presencia de nitrato de plomo, como potenciales agentes que pueden integrarse en procesos que impulsan nuevas tecnologías de biorremediación.

ABSTRACT Lead (Pb) is a heavy metal whose physicochemical characteristics make it a persistent environmental pollutant, bioaccumulable and highly toxic. Bioremediation emerges as an alternative with multiple advantages compared to conventional treatments to remove contaminants such as heavy metals from wastewater, based on the tolerance capacities and/or resistance mechanisms of microorganisms. In order to know the tolerance of Pseudomonas spp. to the lead present in contaminated waters, four native isolates were obtained, coming from wastewater collected in the north from Aburrá Valley River, which were characterized biochemically. Tolerance bioassay was carried out in different concentrations of lead by agar diffusion, as a screening test, and determination of the minimum inhibitory concentration, determining the viability of the microorganism in each exposure. There was no significant difference for lead tolerance between the isolates, identified biochemically as Pseudomonas aeruginosa, nor between the different concentrations of lead to which the isolates were exposed. From these results, we discuss about the mechanisms reported by different authors, by means of which Pseudomonas spp. can act in the presence of lead. In this way, it is concluded that the isolates of Pseudomonas spp. they present tolerance and/or resistance mechanisms up to 2500 mg/L in the presence of lead nitrate, as potential agents that can be integrated into processes that promote new bioremediation technologies.

[Children's non-carcinogenic health risk assessment of heavy metals exposure to residential indoor dust around an e-waste dismantling area in South China].

Objective: To evaluate the non-carcinogenic health risk of heavy metals (As, Cd, Cr, Cu, Mn, Pb and Zn) in residential indoor dust for young children around an e-waste dismantling area in South China. Methods: A village around an e-waste dismantling area in South China was selected as a research site in October 2016. Convenience sampling method was used to select 36 houses in the village and 36 dust samples were collected by vacuum cleaner. The concentrations of heavy metals (Cd, Cr, Cu, Mn, Pb and Zn) in each sample were determined and expressed by the average value. Non-carcinogenic health risk assessment was conducted using the US Environmental Protection Agency (EPA) Health Risk Assessment (HRA) model, the American Toxicology and Disease Registry (ATSDR) Target-organ Toxicity Dose (TTD) approach and the ATSDR Binary Weight-of-Evidence (BINWOE) model. Results: The mean ± SD of concentrations of As, Cd, Cr, Cu, Mn, Pb and Zn were (48.90±33.91), (5.95±3.89), (173.57±580.37), (412.71±1 190.00), (612.82±540.70), (297.41±293.22) and (1 052.81±1 156.48) mg/kg, respectively. The HI value of TTD (2.670) and BINWOE (2.933) were higher than the safety threshold of EPA recommended non-carcinogenic health risk. The HI value of TTD and BINWOE were 1.93 and 2.12 times higher than the HI value of HRA (1.386). Conclusion: There was non-carcinogenic health risk of heavy metals (As, Cd, Cr, Cu, Mn, Pb and Zn) via residential indoor dust around the e-waste dismantling area for local children.

[Impact of informal e-waste recycling on human health].

Increasing e-waste has become a major problem for global environment and public health. In the process of dismantling and recycling of disordered electronic waste, heavy metals such as lead and brominated flame retardants and organic substances are released into environmental media such as air, soil, dust and water, which is harmful to the health of local residents. Taking an e-waste dismantling area in Guangdong Province as an example, this paper reviews exposure levels of heavy metals and organic matters in e-waste recycling areas in China, as well as the health effects of local residents. Previous studies have found that e-waste recycling activities led to serious environmental pollution and high exposure levels of heavy metals and organic matters in local residents, which has a certain impact on the physiological functions of various human systems. The establishment of a centralized dismantling zone can effectively reduce the load level of various pollutants.

Nickel and Chromium Ion Levels in Hair and Gingival Crevicular Fluid with the Corrosion of Brackets in Orthodontic Patients: A Longitudinal Study

Objective: To assess the levels of nickel and chromium ions in hair and Gingival Crevicular Fluid (GCF) of orthodontic patients and to evaluate the corrosion of orthodontic bracket surfaces. Material and Methods: Nickel and chromium ion concentrations were measured in hair and GCF of 15 patients (9 females and 6 males, aged 16-28 years old) who had fixed orthodontic treatment using atomic absorption spectroscopy. The samples were taken before treatment (baseline), 4, 8, and 16 months later during treatment. Along with ionic sampling, microscopic sampling was done. One of each patient brackets was removed to get 15 brackets per group. Five brackets were taken randomly from each group to be examined under scanning electron microscope (SEM). Data obtained were analyzed using paired t-tests. Results: After 16 months, compared with the baseline, average hair nickel level changed from 0.125 µg/g to 0.956 µg/g with statistically significant difference (p=0.00); average chromium level changed from 0.090 µg/g to 0.295 µg/g but no significant difference (p>0.05); average GCF nickel level changed from 3.335 µg/g to 10.410 µg/g; average chromium level changed from 1.859 µg/g to 9.818 µg/g. Both of these increases were significant (p=0.000). SEM examinations showed that the corrosion on brackets was seen in the fourth month, and more severely visible after 8 and 16 months of uses. Conclusion: After 16 months of treatment, compared with the baseline, the hair nickel level was increased by 7.7 times; while for chromium was by 3.3 times. Gingival crevicular fluid nickel level was increased by 3.1 times and chromium level was by 5.3 times. The longer time of treatment, the more ions released and the more corrosion of brackets will be.

A versatile quantitative microdroplet elemental imaging method optimised for integration in biochemical workflows for low-volume samples.

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analysis of µ-droplets is becoming an attractive alternative for detecting and quantifying elements in biological samples. With minimal sample preparation required and detection limits comparable to solution nebulisation ICP-MS, µ-droplets have substantial advantages over traditional elemental detection, particularly for low volumes, such as aliquots taken from samples required for multiple independent biochemical assays, or fluids and tissues where elements of interest exist at native concentrations not suited to the necessary dilution steps required for solution nebulisation ICP-MS. However, the characteristics of µ-droplet residue deposition are heavily dependent on the matrix, and potential effects on signal suppression or enhancement have not been fully characterised. We present a validated and flexible high-throughput method for quantification of elements in µ-droplets using LA-ICP-MS imaging and matrix-matched external calibrants. Imaging the entire µ-droplet area removes analytical uncertainty arising from the often-heterogenous distribution when compared to radial or bisecting line scans that capture only a small portion of the droplet residue. We examined the effects of common matrices found in a standard biochemistry workflow, including native protein and salt contents, as well as reagents used in typical preparation steps for concurrent biochemical assays, such as total protein quantification and enzyme activity assays. We found that matrix composition results in systemic, concentration-dependent signal enhancement and suppression for carbon, whereas high sodium content has a specific space-charge-like suppression effect on high masses. We confirmed the accuracy of our method using both a certified serum standard (Seronorm™ L1) and independent measurements of analysed samples by solution nebulisation ICP-MS, then tested the specificity and reproducibility by examining spinal cord tissue homogenates from SOD1-G93A transgenic mice with a known molecular phenotype of increased copper- and zinc-binding superoxide dismutase-1 expression and altered copper-to-zinc stoichiometry. The method presented is rapid and transferable to multiple other biological matrices and allows high-throughput analysis of low-volume samples with sensitivity comparable to standard solution nebulisation ICP-MS protocols. Graphical Abstract ᅟ.

Impact of informal e-waste recycling on human health / 中华预防医学杂志

Increasing e-waste has become a major problem for global environment and public health. In the process of dismantling and recycling of disordered electronic waste, heavy metals such as lead and brominated flame retardants and organic substances are released into environmental media such as air, soil, dust and water, which is harmful to the health of local residents. Taking an e-waste dismantling area in Guangdong Province as an example, this paper reviews exposure levels of heavy metals and organic matters in e-waste recycling areas in China, as well as the health effects of local residents. Previous studies have found that e-waste recycling activities led to serious environmental pollution and high exposure levels of heavy metals and organic matters in local residents, which has a certain impact on the physiological functions of various human systems. The establishment of a centralized dismantling zone can effectively reduce the load level of various pollutants.

Children′s non-carcinogenic health risk assessment of heavy metals exposure to residential indoor dust around an e-waste dismantling area in South China / 中华预防医学杂志

Objective@#To evaluate the non-carcinogenic health risk of heavy metals (As, Cd, Cr, Cu, Mn, Pb and Zn) in residential indoor dust for young children around an e-waste dismantling area in South China.@*Methods@#A village around an e-waste dismantling area in South China was selected as a research site in October 2016. Convenience sampling method was used to select 36 houses in the village and 36 dust samples were collected by vacuum cleaner. The concentrations of heavy metals (Cd, Cr, Cu, Mn, Pb and Zn) in each sample were determined and expressed by the average value. Non-carcinogenic health risk assessment was conducted using the US Environmental Protection Agency (EPA) Health Risk Assessment (HRA) model, the American Toxicology and Disease Registry (ATSDR) Target-organ Toxicity Dose (TTD) approach and the ATSDR Binary Weight-of-Evidence (BINWOE) model.@*Results@#The mean ± SD of concentrations of As, Cd, Cr, Cu, Mn, Pb and Zn were (48.90±33.91), (5.95±3.89), (173.57±580.37), (412.71±1 190.00), (612.82±540.70), (297.41±293.22) and (1 052.81±1 156.48) mg/kg, respectively. The HI value of TTD (2.670) and BINWOE (2.933) were higher than the safety threshold of EPA recommended non-carcinogenic health risk. The HI value of TTD and BINWOE were 1.93 and 2.12 times higher than the HI value of HRA (1.386).@*Conclusion@#There was non-carcinogenic health risk of heavy metals (As, Cd, Cr, Cu, Mn, Pb and Zn) via residential indoor dust around the e-waste dismantling area for local children.

Switchable fluorescence of MoS2 quantum dots: a multifunctional probe for sensing of chromium(VI), ascorbic acid, and alkaline phosphatase activity.

A simple strategy for modulating the fluorescence of MoS2 quantum dots (QDs) is described. The fluorescence of MoS2 QDs was firstly switched off by the addition of Cr(VI), and the quenched fluorescence was further switched on by introducing ascorbic acid (AA) into the mixture. The fluorescence quenching of MoS2 QDs by Cr(VI) was attributed to the fluorescence inner filter effect. After the addition of AA, Cr(VI) was reduced to Cr(III), and the fluorescence was restored. This finding has been applied for the fluorescent sensing of Cr(VI) in drinking water and AA in serum samples. In addition, the present method has been extended for turn-on sensing of an important biomarker alkaline phosphatase (ALP). There is a linear relationship between the fluorescence intensity and the concentrations of ALP in the range from 2.5 to 50 U/L, and the limit of detection is 0.34 U/L. The results showed MoS2 QDs hold great potential as a multifunctional fluorescent probe for the detection of metal ions, biological small molecules, and proteins. Graphical abstract The fluorescence of MoS2 QDs can be switched off by Cr(VI), and the quenched fluorescence can be further switched on by the addition of ascorbic acid or enzymatically generated ascorbic acid. This allows the selective detection of Cr(VI), ascorbic acid, and alkaline phosphatase based on the fluorescence of MoS2 QDs.

Ultrafiltration binding analyses of glycated albumin with a 3D-printed syringe attachment.

Protein-ligand binding assays facilitate the understanding of biomolecular interactions. Classical equilibrium dialysis methods are often used for accurate determination of binding properties. While accurate, the long equilibration times associated with the technique (> 6 h) hinder throughput. Here, in an attempt to gather high-accuracy results while reducing total analysis time, a low pressure ultrafiltration method that relies on a simple membrane-containing syringe attachment was developed. A minimal portion (1-2%) of the solution containing the binding analytes of interest is driven through the membrane pores and collected for analysis. Specifically, the device was used to investigate the binding affinity between Zn2+ and either normal human serum albumin (nHSA) or a commercially purchased glycated human serum albumin (gHSA). Both of these ligand/protein-binding systems have implications in type 1 diabetes. The device was then used to investigate the binding between the various albumin types and C-peptide, the 31 amino acid peptide that is co-secreted with insulin from pancreatic ß cells. Results for nHSA/Zn2+ binding obtained using the ultrafiltration method (Kd = 5.77 ± 0.19 × 10-7 M) were statistically equivalent with results reported using other methods. Importantly, the amount of Zn2+ bound to the nHSA was significantly different from the gHSA (97 ± 2% protein bound vs. 91 ± 3%, respectively p < 0.05). The binding affinity of C-peptide to nHSA (Kd = 2.4 ± 0.3 × 10-6 M) agreed with values reported in the literature using standard techniques. Unlike Zn2+ binding, the binding of C-peptide to nHSA was statistically equal to its binding to gHSA (77.7 ± 6.2 and 78.8 ± 7.4%, respectively), suggesting that C-peptide replacement therapy in people with T1D may be strongly dependent upon the characteristics of Zn2+ binding to human serum albumin. Graphical abstract ᅟ.

Fractionation of cadmium in tobacco and cigarette smoke condensate using XANES and sequential leaching with ICP-MS/MS.

Fractionation data for cadmium in tobacco products, as obtained by sequential leaching of cadmium species with ICP-MS/MS analysis, and separately by X-ray absorption near edge structure (XANES) are presented here for the first time. The total amount of cadmium found in 3R4F cigarette cut tobacco was 1526 ± 42 µg kg-1, of which 5% was found in the smoke under ISO smoking conditions. XANES analysis showed that Cd in tobacco, cigarette smoke and ash was present in the + 2 oxidation state. Examination of the gas-particle partitioning of smoke cadmium suggests that Cd in mainstream smoke is best viewed as semi-volatile, existing in both particulate and gas phases. Sequential extraction of trapped tobacco smoke was carried out to get a deeper insight into the chemistry of cigarette smoke cadmium compounds. Consecutive extractions with ultrapure water, dilute (1%) nitric acid and 10% nitric acid led to extraction of a total amount of Cd which agreed with that obtained after microwave digestion of the whole sample, suggesting that cadmium was quantitatively leachable into aqueous/acidic solutions. Most Cd (~ 90% of the total Cd in the smoke condensate) was extracted into dilute nitric acid (likely as CdO, Cd(OH)2 and CdCO3) with a minor percentage (3%) extracted into water (likely as CdCl2) and in 10% nitric acid (likely as CdS). Extraction of trapped mainstream smoke with pentane, followed by ICP-MS/MS analysis, to examine the possible presence of organocadmium in 3R4F tobacco smoke, did not show the presence of organocadmium compounds above the method LOQ (2 µg kg-1), possibly due to their reactivity under the experimental conditions. The high selectivity with sufficient sensitivity achieved by ICP-MS/MS was invaluable to quantify Cd (at low µg kg-1levels) simultaneously with sulphur and chlorine in the tobacco smoke fractions of complex matrix. The cadmium chemistry in the smoke, identified in this study, is consistent with both relatively high lung absorption and DNA binding; both potentially important factors for disease progression in smokers. Graphical Abstract This paper provides quantitative fractionation data for cadmium in tobacco and smoke by using sequential leaching with ICPMS and XANES.