Biomass reinforced graphene oxide solid/liquid phase membrane extraction for the measurement of Pb(II) in food samples

Single-Cell Study Unveils Lead Lifespan in Blood Cell Populations Follows a Universal Lognormal Distribution with Individual Skewness

Lead is a widespread environmental hazard that can adversely affect multiple biological functions. Blood cells are the initial targets that face lead exposure. However, a systematic assessment of lead dynamics in blood cells at single-cell resolution is still absent. Herein, C57BL/6 mice were fed with lead-contaminated food. Peripheral blood was harvested at different days. Extracted red blood cells and leukocytes were stained with 19 metal-conjugated antibodies and analyzed by mass cytometry. We quantified the time-lapse lead levels in 12 major blood cell subpopulations and established the distribution of lead heterogeneity. Our results show that the lead levels in all major blood cell subtypes follow lognormal distributions but with distinctively individual skewness. The lognormal distribution suggests a multiplicative accumulation of lead with stochastic turnover of cells, which allows us to estimate the lead lifespan of different blood cell populations by calculating the distribution skewness. These findings suggest that lead accumulation by single blood cells follows a stochastic multiplicative process.

Novel bionanomaterial based on Spirulina maxima algae and graphene oxide for lead microextraction and determination in water and infant beverages

A new hybrid bionanomaterial composed of graphene oxide (GO) and Spirulina maxima (SM) algae was synthesized and applied to develop a preconcentration method based on the dispersive micro-solid phase extraction (D-μ-SPE) technique for the determination of Pb in water and infant beverages. In this work, Pb(II) was extracted with 3 mg of the hybrid bionanomaterial (GO@SM) followed by a back-extraction step using 500 µL of 0.6 mol L-1 HCl. Then, a 1.5 × 10-3 mol L-1 dithizone solution was added to the sample containing the analyte to form a purplish red-colored complex for its detection by UV-Vis spectrophotometry at 553 nm. An extraction efficiency of 98% was obtained after optimization of experimental variables such as GO@SM mass, pH, sample volume, type, and time of agitation. A detection limit of 1 μg L-1 and a relative standard deviation of 3.5% (at 5 μg L-1 Pb(II), n = 10) were achieved. The calibration linear range was obtained between 3.3 and 95 µg L-1 Pb(II). The proposed method was successfully applied for the preconcentration and determination of Pb(II) in infant beverages. Finally, the greenness degree of the D-µ-SPE method was evaluated using the Analytical GREEnness calculator (AGREE), obtaining a score of 0.62.

Hybrid biomaterials to preconcentrate and determine toxic metals and metalloids: a review

Toxic elements represent a serious threat to the environment and cause harmful effects on different environmental components, even at trace levels. These toxic elements are often difficult to detect through the typical instrumentation of an analytical laboratory because they are found at very low concentrations in matrices such as food and water. Therefore, preconcentration plays a fundamental role since it allows the effects of the matrix to be minimized, thus reaching lower detection limits and greater sensitivity of detection techniques. In recent years, solid-phase extraction has been successfully used for the preconcentration of metals as an environmentally friendly technique due to the fact that it eliminates or minimizes the use of reagents and solvents and offers reduced analysis times and low generation of waste in the laboratory. Hybrid biomaterials are low-cost, eco-friendly, and useful as efficient solid phases for the preconcentration of elements. In this review, recent investigations based on the use of hybrid biomaterials for the preconcentration and determination of toxic metals are presented and discussed, given special attention to bionanomaterials. A brief description of hybrid biomaterials often used for analytical purposes, as well as analytical techniques mostly used to characterize the hybrid biomaterials, is explained. Finally, the future prospects that encourage the search for new hybrid biomaterials are commented upon.

Application of Graphene and its Derivatives in Detecting Hazardous Substances in Food: A Comprehensive Review

Graphene and its derivatives have been a burning issue in the last 10 years. Although many reviews described its application in electrochemical detection, few were focused on food detection. Herein, we reviewed the recent progress in applying graphene and composite materials in food detection during the past 10 years. We pay attention to food coloring materials, pesticides, antibiotics, heavy metal ion residues, and other common hazards. The advantages of graphene composites in electrochemical detection are described in detail. The differences between electrochemical detection involving graphene and traditional inherent food detection are analyzed and compared in depth. The results proved that electrochemical food detection based on graphene composites is more beneficial. The current defects and deficiencies in graphene composite modified electrode development are discussed, and the application prospects and direction of graphene in future food detection are forecasted.

Engineering Grey Nanosystem as Activatable Ratio-colorimetric Probe for Detection of Lead Ions in Preserved Egg

A grey system based on the principle of complementary colors was constructed as an activatable probe for the sensitive and specific ratio-colorimetric detection lead ions (Pb²⁺) in a complex food matrix. This grey system was prepared by mixing purple-red AuNP-capped glutathione (GSH) and green-blue sulfonated pigment green 7 (SPG7), to create the SPG7/AuNP probe. In the presence of Pb²⁺, the strong chelation of Pb²⁺ with GSH could trigger the aggregation of AuNPs, leading to the color activation of SPG7. Hence, the absorbance ratio A_523nm/A_628nm of AuNPs at ∼523 nm and SPG7 at ∼628 nm could be used for highly specific reporting of Pb²⁺ levels with a low detection limit of 0.33 μg/L. Moreover, this probe exhibited promising practical applications in real preserved egg samples with recoveries of 89.2 to 107.5% and relative standard deviations (RSD) in the range of 0.28 to 2.12%, revealing its great potential for harmful substance detection.

Biochars preparation from waste sludge and composts under different carbonization conditions and their Pb(II) adsorption behaviors

This study prepared nine biochars from three biomass wastes (CompostA, CompostB and Sludge) through different carbonization conditions. The adsorption behaviors and mechanisms of these biochars for Pb(II) were tested by a series of adsorption experiments and properties analysis. Preliminary experiments showed biochars obtained from CompostA and Sludge had better Pb(II) adsorption performance than CompostB and the optimum carbonization temperature of CompostA was lower than that of Sludge. Adsorption experimental results demonstrated that CompostA600 (numbers represent carbonization temperatures) had the largest adsorption capacity of 57.34 mg/g for Pb(II) among samples, followed by Sludge800 of 50.00 mg/g. The kinetic adsorption of CompostA600 and Sludge800 were both described by the Nth-order model very well. Pb(II) adsorption of CompostA600 most appropriately followed the Langmuir-Freundlich model and the Redlich-Peterson model. Characterization analysis suggested diverse carbonization temperatures and precursors caused discrepant pore size distributions and element contents, which determined the deposition of lead compound crystals on materials. This study examined the effects of raw materials and carbonization temperatures on obtained biochars and provided an inexpensive and environmental-friendly way for biochar sorbent preparation and heavy metal wastewater treatment.

Highly efficient and cost-effective removal of patulin from apple juice by surface engineering of diatomite with sulfur-functionalized graphene oxide

Patulin (PAT) contamination of apple juice leads to a serious food safety issue. Developing an excellent adsorbent to efficiently remove PAT is more desirable. Herein, a cost-effective and efficient adsorbent (GO-SH/diatomite) with abundant active sites was successfully fabricated via surface engineering of diatomite with sulfur-functionalized graphene oxide (GO-SH) nanosheets, which exhibited excellent selective adsorption capacity toward PAT. The adsorption behavior, adsorption mechanism, stability and cytotoxicity were investigated by systematic studies. The adsorption results showed that its maximum adsorption capacity was 10.68 μg/mg. Moreover, attributed to the specific interaction between PAT and thiol group, more than 90% of PAT was removed from apple juice without any juice quality deterioration. Importantly, the risk of food safety issue of apple juice caused by residual GO-SH/diatomite was negligible due to the properties of easy removal and excellent biocompatibility, which guaranteed its potential application in apple juice industry for PAT removal.