An oligosaccharide marker for rapid authentication of edible bird's nest.

Edible bird's nest (EBN) is a popular and expensive food material. The limited supply and great demand result in the use of adulterants. The authenticity concern is raised due to the lack of appropriate quality markers. Herein, this study aims to provide a specific oligosaccharide marker for rapid EBN authentication. Comparing the benzocaine (ABEE)-labeled saccharide profiles of multiple batches of EBN and adulterants indicates seven unique EBN oligosaccharides. The most abundant one, named BNM001, was selected as a marker and characterized to be Neu5Ac (2-3) Gal by MS and NMR spectra. This new oligosaccharide marker enables a rapid authentication of EBN within 10 min. ABEE labelling of this marker further upgraded the accuracy and sensitivity of the LC-qTOF-MS quantitative analysis. The relative marker content was associated with the quality of EBN products. These results suggest a specific and efficient quality marker for rapid authentication of EBN and related products.

Qualitative and Quantitative Analysis of Ejiao-Related Animal Gelatins through Peptide Markers Using LC-QTOF-MS/MS and Scheduled Multiple Reaction Monitoring (MRM) by LC-QQQ-MS/MS.

Donkey-hide gelatin, also called Ejiao (colla corii asini), is commonly used as a food health supplement and valuable Chinese medicine. Its growing popular demand and short supply make it a target for fraud, and many other animal gelatins can be found as adulterants. Authentication remains a quality concern. Peptide markers were developed by searching the protein database. However, donkeys and horses share the same database, and there is no specific marker for donkeys. Here, solutions are sought following a database-independent strategy. The peptide profiles of authentic samples of different animal gelatins were compared using LC-QTOF-MS/MS. Fourteen specific markers, including four donkey-specific, one horse-specific, three cattle-specific, and six pig-specific peptides, were successfully found. As these donkey-specific peptides are not included in the current proteomics database, their sequences were determined by de novo sequencing. A quantitative LC-QQQ multiple reaction monitoring (MRM) method was further developed to achieve highly sensitive and selective analysis. The specificity and applicability of these markers were confirmed by testing multiple authentic samples and 110 batches of commercial Ejiao products, 57 of which were found to be unqualified. These results suggest that these markers are specific and accurate for authentication purposes.

Qualitative and Quantitative Analysis of Edible Bird's Nest Based on Peptide Markers by LC-QTOF-MS/MS.

Edible bird's nest (EBN) is an expensive health food. There are many adulterants in the market. It remains challenging to discriminate EBN from its adulterants due to a lack of high-specificity markers. Besides, the current markers are confined to soluble fraction of EBN. Here, both soluble and insoluble fractions were analyzed by LC-QTOF-MS/MS. A total of 26 high-specificity peptides that were specific to EBN were selected as qualitative authentication markers. Among them, 10 markers can discriminate EBN from common adulterants, 13 markers discriminate white EBN from grass EBN/common adulterants, and 3 markers discriminate grass EBN from white EBN/common adulterants. Three of them, which showed high signal abundance (Peak area ≥ 106) and satisfactory linearity (R2 ≥ 0.995) with EBN references, were selected as the assay marker; and their peptide sequences were confidently identified by searching database/de novo sequencing. Based on these markers, a qualitative and quantitative analytical method was successfully developed and well-validated in terms of linearity, precision, repeatability, and accuracy. The method was subsequently applied to detect EBN products on the market. The results indicated that more than half of EBN products were not consistent with what the merchants claimed.

A specific and bioactive polysaccharide marker for Cordyceps.

Cordyceps is one of the most expensive and widely used functional foods. But the authenticity is still a concern due to the lack of appropriate markers. By targeting polysaccharides, this study aimed to develop a specific, and bioactive marker for Cordyceps. Firstly, the results of screening tests of 250 samples by examining both genetic markers and polysaccharide profile showed that a unique polysaccharide fraction (named CCP) was particular to the caterpillar parts. Its potential as a marker was further demonstrated by its ability to induce NO and cytokine production in RAW 264.7 cells. CCP was characterized to be an α-1,4-glucan with a branch at C-6 by the conventional structure analyzing and de novo oligosaccharides sequencing. The content of CCP was closely correlated to the traditional classification criteria. Generally, CCP was a marker that simultaneously enables qualitative and quantitative analysis of Cordyceps.

One-Step Thermochemical Conversion of Biomass Waste into Superhydrophobic Carbon Material by Catalytic Pyrolysis.

Preparation of superhydrophobic carbon materials from lignocellulosic biomass waste via one-step carbonization is very difficult due to the existences of polar functional groups and ashes, which are extremely hydrophilic. Herein, superhydrophobic carbon materials can be facilely synthesized by catalytic pyrolysis of biomass waste using FeCl3 as catalyst. The results show that the surface energy of lignin-derived char (CharL) is significantly reduced to 19.25 mN m-1 from 73.29 mN m-1, and the water contact angle increased from 0 to 151.5°, by interaction with FeCl3. Multiple characterizations and control experiments demonstrate that FeCl3 can catalyze the pyrolytic volatiles to form a rough graphite and diamond-like carbon layer that isolates the polar functional groups and ashes on CharL, contributing to the superhydrophobicity of the CharL. The one-step catalytic pyrolysis is able to convert different natural biomass waste (e.g., lignin, cellulose, sawdust, rice husk, maize straw, and pomelo peel) into superhydrophobic carbon materials. This study contributes new information related to the interfacial chemistry during the sustainable utilization of biomass waste.

An oligosaccharide-marker approach to quantify specific polysaccharides in herbal formula by LC-qTOF-MS: Danggui Buxue Tang, a case study.

Polysaccharides have broad bioactivities and are major components of water decoction of herb formulae. However, the quality control of polysaccharides remains a challenge. Oligosaccharide-fragment approach has been considered in elucidating chemical structures of polysaccharides, but never been used for quantitation. Using reference chemicals and a real sample Danggui Buxue Tang (DBT) in this study, an oligosaccharide-marker approach was established to quantify specific polysaccharides. Firstly, linear relationships between parent polysaccharides and hydrolysis-produced daughter oligosaccharides were verified using reference polysaccharides. Then in case of DBT, two fluorescence-labeled oligosaccharides with high specificity to individual parent polysaccharides were selected as markers. They were easily isolated and identified. Their potential in quantification of parent polysaccharides were satisfactorily validated in terms of linearity (r≥0.99), repeatability (RSD ≤ 8.4 %), and spike recovery (≥80 %). This method could be a promising approach for quality assessment of polysaccharides in herbal formulae.

Nontemplating Porous Carbon Material from Polyphosphamide Resin for Supercapacitors.

The nontemplating preparation of porous carbon materials by using specially designed polymer precursors for supercapacitor is attracting considerable research attention because of the more controllable frame structure and easier processes than templating methods. Herein, a deliberately designed cross-linking polyphosphamide resin with defined N and P structure is synthesized and then carbonized to obtain porous carbon material. The as-obtained porous carbon material has a specific surface area of 2,620 m2 g-1, high porosity of 1.49 cm3 g-1, and well-distributed micro/mesoporous carbon structure. Different from activation by post-added NH4H2PO4, the confined N and P in the polymer frame are confirmed to play an important role in pore structure development by forming in situ highly dispersed NH4H2PO4 during carbonization. When evaluated as the electrode material for supercapacitors, the polyphosphamide-resin-based porous carbon material demonstrates excellent capacitance (440 F g-1 under 0.5 A g-1) and high stability (retention of 93% over 10,000 cycles).

Highly stable and selective measurement of Fe3+ ions under environmentally relevant conditions via an excitation-based multiwavelength method using N, S-doped carbon dots.

Fast and accurate detection of Fe3+ under relevant natural conditions is important in environmental monitoring. In this study, an improved and simplified fluorescence method based on the multiwavelength luminescence in the visible region and the avoidance of the self-quenching property of N, S-doped carbon dots (NSC-Dots) was developed for the first time to determine Fe3+ concentration under varied environmental conditions. This method can simultaneously save time and provide accurate information. The as-prepared NSC-Dots exhibit two stable excitation peaks from 200 nm to 450 nm at a fixed emission wavelength (λem = 450 nm). A standard equation (R2 = 0.995) can be derived by measuring the quenching degree of the two peaks and referring to Stern-Volmer theory. Thus, Fe3+ concentration was accurately determined. The interference of the environmentally relevant concentrations of other metal ions, humic acid, and pH on Fe3+ measurement was tested. Results showed that the standard equation can be used to accurately determine Fe3+ concentration within the range of the 95% prediction band. The fast and facile multiwavelength method may facilitate the real-time monitoring of Fe3+ concentration in complex water environments.

The effects of environmental conditions on the enrichment of antibiotics on microplastics in simulated natural water column.

Concerns regarding the release of microplastics (MPs) into the environment led us to explore the relationship between the different environmental factors and physicochemical properties of MPs, as well as the change of interaction between MPs and organic pollutants. In this study, the effects of environmental factors (ageing conditions), such as pH, temperature, ionic strength, ageing time, and humic acid (HA) concentration, on the characteristics of MPs and their adsorption toward tetracycline (TC) were systematically investigated. The results showed that ageing factors such as pH, ionic strength, and temperature were found to have little impact on the adsorptive capacity of MPs for TC. However, MPs aged in HA solution exhibited a significant decreased adsorptive capacity for TC. HA, which has numerous functional groups, can cover the surface of MPs and change their hydrophobicity, thereby reducing the adsorption affinity to TC. The electrostatic repulsion between adsorbed HA and TC molecules may also decrease the adsorption of TC. In addition, the competing effect of HA for adsorption sites on the surface of MPs further reduces the adsorption of TC. The data presented in this work provide useful information for understanding the transfer of antibiotics by aged MPs, which is of fundamental importance to assess the environmental impact of MPs.

Relationship between GSTM1/GSTT1 null genotypes and renal cell carcinoma risk: a meta-analysis.

The results from the published studies on the relationship between GSTM1/GSTT1 null genotypes and renal cell carcinoma (RCC) risk are still conflicting. This meta-analysis was performed to evaluate the relationship between GSTM1/GSTT1 null genotypes and RCC susceptibility. Association studies were identified from the databases of PubMed, Embase, Cochrane Library, and CBM-disc (China Biological Medicine Database) on 1 February 2012, and eligible investigations from 1950 to 2012 were synthesized using meta-analysis method. Results were expressed as odds ratios (ORs) for dichotomous data, and 95% confidence intervals (CIs) were also calculated. Six studies were identified for the analysis of association between polymorphic deletion of GSTM1/GSTT1 and RCC risk. There was no association between GSTM1/GSTT1 null genotype and RCC susceptibility (GSTM1: N = 6, p-heterogeneity = 0.07, OR = 1.07, 95% CI: 0.85-1.35, p = 0.57; GSTT1: N = 6, p-heterogeneity < 0.00001, OR = 0.98, 95% CI: 0.58-1.65, p = 0.94). Interestingly, null genotype of GSTT1 was associated with RCC risk in Caucasians and Asians (Caucasians: N = 4, p-heterogeneity = 0.38, OR = 0.76, 95% CI: 0.61-0.95, p = 0.01; Asians: N = 1, OR = 2.39, 95% CI: 1.63-3.51, p < 0.00001). For the GSTM1-GSTT1 interaction analysis, the dual null genotype of GSTM1/GSTT1 was not significantly associated with RCC susceptibility (N = 4, p-heterogeneity = 0.006, OR = 1.17, 95% CI: 0.98-1.39, p = 0.09). However, the dual null genotype of GSTM1-GSTT1 was associated with RCC risk in Asians (N = 1, OR = 2.06, 95% CI: 1.36-3.13, p = 0.007). In conclusion, our study results suggest that GSTT1 null genotype is associated with the RCC susceptibility in Caucasians and Asians, and the dual null genotype of GSTM1-GSTT1 is associated with RCC risk in Asians. However, more genetic epidemiological investigations are required to further explore this relationship.