Constructing core-shell structured Co3O4-MnWO4 composite photoelectrode with superior PEC water purification performance.

Semiconductor photoelectrocatalytic (PEC) technology is one of the most effective methods for removing organic pollutants from wastewater in advanced oxidation processes(AOPs). The selection of suitable semiconductor materials as photoanodes is a crucial factor for achieving superior PEC performance. Here, a core-shell structured Co3O4-MnWO4 architecture is created by enveloping MnWO4 nanoparticles onto the surface of Co3O4 nanowires through a two-step hydrothermal process. The optimized Co3O4-MnWO4-5 photoelectrode showed superior PEC degradation efficiency for KN-R (∼91.2% in 2 h) and durable stability (the accelerated lifetime reached ∼9100 s at a current density of 50 mA cm-2). Three actual wastewaters were also collected to verify the practical applicability of the photoelectrode.The energy consumption was measured at 4.48 kWhm-3, with a COD removal efficiency of 83% and a decolorization rate of 98%. These results demonstrate the excellent performance and promising application of the photoelectrode. The enhancement of PEC performance for the core-shell structured Co3O4-MnWO4 architecture can be attributed to the suitable energy band structure of the Co3O4-MnWO4 composite, higher OEP, larger electrochemical active surface area, accelerated transport of interface carriers, and lower charge transfer resistance. The energy band structure of the Co3O4-MnWO4 composite showed a strong redox ability to induce electrons/holes (e-/h+), which enhances the generation of intermediate active species (hydroxyl radical ·OH and superoxide radicals ·O2-). Therefore, the rationally designed core-shell structured Co3O4-MnWO4 architecture exhibited excellent practical applicability in the degradation of organic pollutants.

Emerging Data Processing Methods for Single-Entity Electrochemistry.

Single-entity electrochemistry is a powerful tool that enables the study of electrochemical processes at interfaces and provides insights into the intrinsic chemical and structural heterogeneities of individual entities. Signal processing is a critical aspect of single-entity electrochemical measurements and can be used for data recognition, classification, and interpretation. In this review, we summarize the recent five-year advances in signal processing techniques for single-entity electrochemistry and highlight their importance in obtaining high-quality data and extracting effective features from electrochemical signals, which are generally applicable in single-entity electrochemistry. Moreover, we shed light on electrochemical noise analysis to obtain single-molecule frequency fingerprint spectra that can provide rich information about the ion networks at the interface. By incorporating advanced data analysis tools and artificial intelligence algorithms, single-entity electrochemical measurements would revolutionize the field of single-entity analysis, leading to new fundamental discoveries.

Unlocking a Type-II CoO@BiVO4 Heterostructure for Wastewater Purification.

Developing a semiconductor-based heterostructure photoanode is crucial in improving the photoelectrocatalytic (PEC) efficiency for degrading refractory organic pollutants. Nevertheless, the PEC performance of the photoanodes is usually restricted by electron/hole pair recombination, oxygen evolution, and slow electron transfer. Herein, a novel CoO@BiVO4 nanowire array film (Ti/CoO@BiVO4) with n-type semiconductor characteristics was prepared via a straightforward hydrothermal method. The optimized Ti/CoO@BiVO4 electrode exhibited excellent PEC decolorization efficiency of active brilliant blue KN-R (∼92.8%) and long-term stability, outperforming recent reports. The insight reason for enhancing the PEC degradation efficiency of the Ti/CoO@BiVO4 electrodes can be attributed to the large electrochemical active area, low charge transfer resistance, and negative flat band potential. The formation of a type-II heterostructure was investigated between CoO and BiVO4 further to promote the generation and separation efficiency of electron/hole pairs, indicating that the optimized Ti/CoO@BiVO4 electrode has the potential for the water PEC degradation ability and superior service life.

Structure-activity relationship of Caulerpa lentillifera polysaccharide in inhibiting lipid digestion.

Caulerpa lentillifera polysaccharide (CLP) has been characterized as a sulfated polysaccharide which can effectively inhibit lipid digestion. However, little information was known regarding its inhibitory mechanisms. In the present study, desulfation and degradation were conducted to prepare the derivatives of CLP, and a series of chemical and spectroscopic methods were used to elucidate the structure-activity relationship of CLP on the inhibitory effect of lipid digestion. Results revealed that CLP possessed excellent binding capacities for sodium cholate, sodium glycocholate, and sodium taurocholate. In addition, CLP can effectively inhibit lipase activity by quenching the fluorescence intensity, changing the secondary structure, and decreasing the UV-Vis absorbance. Of note, sulfate groups in CLP took a vital role in inhibiting lipase activity, while the molecular weight of CLP showed a positive correlation with the binding activities of bile acids. Furthermore, adding CLP into the whey protein isolate (WPI) emulsion system also impeded lipid digestion, indicating that CLP can be a potential reduced-fat nutraceutical used in food emulsion systems.

Orally administrated fucoidan and its low-molecular-weight derivatives are absorbed differentially to alleviate coagulation and thrombosis.

Thrombosis is a serious threat to human health and life. Fucoidan, a sulfated polysaccharide from brown algae, could prevent coagulation and thrombus after intravenous administration. However, more efforts are still needed to develop its oral agent. In the present study, the absorption and excretion of fucoidan (90.8 kDa) and its degradation products, Dfuc1 (19.2 kDa) and Dfuc2 (5.5 kDa), were determined by HPLC-MS/MS after acid degradation and 1-phenyl-3-methyl-5-pyrazolone derivatization, and their anticoagulation and antithrombotic activities were evaluated in vivo after oral administration. Results showed that the maximum concentrations of fucoidan, Dfuc1 and Dfuc2 in rat plasma all achieved at 2 h after oral administration (150 mg/kg), and they were 41.1 ± 10.6 µg/mL, 45.3 ± 18.5 µg/mL and 59.3 ± 13.7 µg/mL, respectively. In addition, fucoidan, Dfuc1 and Dfuc2 could all prolong the activated partial thromboplastin time in vivo from 23.7 ± 2.7 s (blank control) to 25.1 ± 2.6 s, 27.1 ± 1.7 s and 29.4 ± 3.6 s, respectively. Moreover, fucoidan and its degradation products showed similar antithrombotic effect in carrageenan-induced thrombosis mice, and untargeted metabolomics analysis revealed that they all markedly regulated the carrageenan-induced metabolite disorders, especially the arachidonic acid metabolism. Thus, the degradation products of fucoidan with lower molecular weights are more attractive for the development of oral antithrombotic agents.

Structural characterization of a fucoidan from Ascophyllum nodosum and comparison of its protective effect against cellular oxidative stress with its analogues.

In the present study, a fucoidan fraction (ANP-3) was isolated from Ascophyllum nodosum, and the combined application of desulfation, methylation, HPGPC, HPLC-MSn, FT-IR, GC-MS, NMR, and Congo red test elucidated ANP-3 (124.5 kDa) as a triple-helical sulfated polysaccharide constituted by →2)-α-Fucp3S-(1→, →3)-α-Fucp2S4S-(1→, →3,6)-ß-Galp4S-(1→, →3,6)-ß-Manp4S-(1→, →3,6)-ß-Galp4S-(1→，→6)-ß-Manp-(1→, →3)-ß-Galp-(1→, α-Fucp-(1→, and α-GlcAp-(1→ residues. To better understand the relationship between the fucoidan structure of A. nodosum and protective effects against oxidative stress, two fractions ANP-6 and ANP-7 were used as contrast. ANP-6 (63.2 kDa) exhibited no protective effect against H2O2-induced oxidative stress. However, ANP-3 and ANP-7 with the same molecular weight of 124.5 kDa could protect against oxidative stress by down-regulating reactive oxygen species (ROS) and malondialdehyde (MDA) levels and up-regulating total antioxidant capability (T-AOC), superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPX) activities. Then metabolites analysis indicated that arginine biosynthesis and phenylalanine, tyrosine, and tryptophan biosynthesis metabolic pathways and metabolic biomarkers such as betaine were involved in the effects of ANP-3 and ANP-7. The better protective effect of ANP-7 compared to that of ANP-3 could be attributed to its relatively higher molecular weight, sulfate substitution and →6)-ß-Galp-(1→ content, and lower uronic acid content.

Unveiling Hierarchical Dendritic Co3O4-SnO2 Heterostructure for Efficient Water Purification.

The construction of a desirable, environmentally friendly, and cost-effective nanoheterostructure photoanode to treat refractory organics is critical and challenging. Herein, we unveiled a hierarchical dendritic Co3O4-SnO2 heterostructure via a sequential hydrothermal process. The time of the secondary hydrothermal process can control the size of the ultrathin SnO2 nanosheets on the basis of the Ostwald solidification mass conservation principle. Ti/Co3O4-SnO2-168h with critical growth size demonstrated a photoelectrocatalysis degradation rate of ∼93.3% for a high dye concentrate of 90 mg/L with acceptable long-term cyclability and durability over reported Co3O4-based electrodes because of the large electrochemically active area, low charge transfer resistance, and high photocurrent intensity. To gain insight into the photoelectric synergy, we proposed a type-II heterojunction between Co3O4 and SnO2, which prevents photogenerated carriers' recombination and improves the generation of dominant active species •O2-, 1O2, and h+. This work uncovered the Ti/Co3O4-SnO2-168 as a promising catalyst and provided a simple and inexpensive assembly strategy to obtain binary integrated nanohybrids with targeted functionalities.

Characterization and Gel Properties of Low-Molecular-Weight Carrageenans Prepared by Photocatalytic Degradation.

Low-molecular-weight carrageenan has attracted great interest because it shows advantages in solubility, absorption efficiency, and bioavailability compared to original carrageenan. However more environment-friendly and efficient methods to prepare low-molecular-weight carrageenan are still in great need. In the present study, a photocatalytic degradation method with only TiO2 has been developed and it could decrease the average molecular weight of κ-carrageenan to 4 kDa within 6 h. The comparison of the chemical compositions of the degradation products with those of carrageenan by FT-IR, NMR, etc., indicates no obvious removement of sulfate group, which is essential for bioactivities. Then 20 carrageenan oligosaccharides in the degradation products were identified by HPLC-MSn, and 75% of them possessed AnGal or its decarbonylated derivative at their reducing end, indicating that photocatalysis is preferential to break the glycosidic bond of AnGal. Moreover, the analysis results rheology and Cryo-SEM demonstrated that the gel property decreased gradually. Therefore, the present study demonstrated that the photocatalytic method with TiO2 as the only catalyst has the potential to prepare low-molecular-weight carrageenan with high sulfation degree and low viscosity, and it also proposed the degradation rules after characterizing the degradation products. Thus, the present study provides an effective green method for the degradation of carrageenan.

Preparation, Characterization, and Antioxidant Properties of Phycocyanin Complexes Based on Sodium Alginate and Lysozyme.

In this study, phycocyanin-sodium alginate/lysozyme complex (PC-SLC) was prepared for the first time and characterized by UV spectroscopy, Fourier transform infrared spectroscopy (FT-IR), and circular dichroism spectroscopy (CD). The stability of PC-SLC under light, temperature, pH and simulated gastrointestinal fluid was investigated. The scavenging ability of the complexes against DPPH and ABTS radicals was determined. The results showed that the complex formed by the mass ratio of SA-LZM of 0.1 showed the highest PC encapsulation rate (89.9 ± 0.374%). The combination of SA and LZM changed the secondary conformation of PC. The PC-SLC complex shows an irregular spherical structure and the spheres are clustered together. Compared with phycocyanin (PC), its thermal stability was obviously improved, but it was still greatly influenced by light. It could exist stably in simulated gastric fluid (SGF) for 2 h and be slowly digested in simulated intestinal fluid (SIF), which helped to promote the absorption of nutrients in the intestinal tract. Meanwhile, the complex PC-SLC showed high scavenging ability for DPPH and ABTS radicals. It can be concluded that the complexes have good antioxidant activity. This study provides an idea for the construction of PC delivery system and makes it more widely used in food industry and other fields.

ACE inhibitory activities of two peptides derived from Volutharpa ampullacea perryi hydrolysate and their protective effects on H2O2 induced HUVECs injury.

The purpose of this study is to explore the effects of IVTNWDDMEK and VGPAGPRG, two angiotensin I-converting enzyme (ACE) inhibitory peptides purified from Volutharpa ampullacea perryi, on ACE's two domains and on nitric oxide (NO), endothelin-1(ET-1) production in human vascular endothelial cells (HUVECs). In addition, we sought to investigate the effects of these two peptides on HUVECs injury induced by H2O2. The results indicated that the inhibition of the ACE C-domain was significantly higher than that of the ACE N-domain by these two peptides. Molecular dynamics (MD) analysis revealed that the hydrogen bonds interactions between ACE and two peptides, the chelation between peptides and Zn2+ both play important role, which might contribute significantly to the ACE inhibitory activity. Two peptides significantly increase NO and ET-1 production in a dose-dependent manner and protects against hydrogen peroxide-induced HUVEC cell injury. The reported results also show that two peptides up-regulated the expression of nuclear factor erythroid 2-related factor (Nrf2) and heme oxygenase-1 (HO-1), and reduce the accumulation of reactive oxygen species (ROS) and malondialdehyde (MDA). Our study indicated that IVTNWDDMEK and VGPAGPRG could be potent ACE inhibitors and Volutharpa ampullacea perryi is a good source of bioactive peptides, which provided a theoretical basis for the broad application of two selected peptides as functional food with anti-hypertensive activity.

Preparation of Low-Molecular-Weight Fucoidan with Anticoagulant Activity by Photocatalytic Degradation Method.

It is a challenge to degrade sulfated polysaccharides without stripping sulfate groups. In the present study, a photocatalytic method was applied to degrade fucoidan, a sulfated polysaccharide from brown algae. The degradation with varying addition amounts of H2O2 and TiO2 were monitored by high performance gel permeation chromatography (HPGPC) and thin layer chromatography (TLC), and fucoidan was efficiently degraded with 5% TiO2 and 0.95% H2O2. A comparison of the chemical compositions of 2 products obtained after 0.5 h and 3 h illumination, DF-0.5 (average Mw 90 kDa) and DF-3 (average Mw 3 kDa), respectively, with those of fucoidan indicates the photocatalytic degradation did not strip the sulfate groups, but reduced the galactose/fucose ratio. Moreover, 12 oligosaccharides in DF-3 were identified by HPLC-ESI-MSn and 10 of them were sulfated. In addition, DF-0.5 showed anticoagulant activity as strong as fucoidan while DF-3 could specifically prolong the activated partial thromboplastin time. All samples exerted inhibition effects on the intrinsic pathway FXII in a dose-dependent manner. Thus, photocatalytic degradation demonstrated the potential to prepare sulfated low-molecular-weight fucoidan with anticoagulant activity.

Study on the domain selective inhibition of angiotensin-converting enzyme (ACE) by food-derived tyrosine-containing dipeptides.

In this article, the selective inhibition of several tyrosine-containing dipeptides on N and C domain of ACE (angiotensin-converting enzyme) was studied, and the interaction mode of ACE and inhibitors was simulated by molecular docking. MTT assay was used to detect the effect of dipeptide on human umbilical vein endothelial cells (HUVEC). The results showed that the food-derived dipeptides AY (Ala-Tyr), LY (Leu-Tyr), and IY (Ile-Tyr) containing tyrosine at the C-terminal were favorable structures for selective inhibition of ACE C-domain. These dipeptides showed competitive and mixed inhibition patterns, while the dipeptides EY (Glu-Tyr), RY (Arg-Tyr), FY (Phe-Tyr), and SY (Ser-Tyr) showed noncompetitive inhibition. Food-derived dipeptides containing tyrosine have no cytotoxicity on HUVEC cells, which provides a basis for the application of food-derived tyrosine dipeptides as antihypertensive peptides. This study provides a theoretical basis for exploring the selective inhibition mechanism of ACE inhibitory peptides containing tyrosine residue. PRACTICAL APPLICATIONS: Angiotensin-converting enzyme (ACE) is a two-domain dipeptidyl carboxypeptidase, which is a key enzyme to regulate blood pressure. ACE has two active sites, C- and N-domain, which have high catalytic activity. Although the amino acid sequences of the two active sites have 60% similarity, there are some differences in structure and function. The action mechanism of ACE domain should be clarified, and the structure-activity relationship between inhibitors and ACE domain has not been systematically studied. The aim of this study was to identify the selective inhibitory effect of food-derived tyrosine dipeptides on the domain of ACE. This provides a new idea for finding new antihypertensive drugs with less side effects.

Engineering Cationic Sulfur-Doped Co3O4 Architectures with Exposing High-Reactive (112) Facets for Photoelectrocatalytic Water Purification.

Promoting the generation of intermediate active species (superoxide radical (•O2-)) is an important and challenging task for water purification by photoelectrocatalytic (PEC) oxidation. Herein, we have constructed hierarchical cationic sulfur-doped Co3O4 architectures with controllable morphology and highly exposed reactive facets by introducing l-cysteine as a capping reagent and sulfur resource via a one-step hydrothermal reaction. The as-obtained cationic sulfur (1.8 mmol l-cysteine) source doped Co3O4 (SC-1.8) architectures with highly exposed (112) facets exhibited superior PEC activities and long-term stability (∼25,000 s) in 1.0 mol·L-1 sulfuric acid for an accelerated reactive brilliant blue KN-R degradation test. Our experimental and theoretical results confirmed that the superior PEC performance of the SC-1.8 architectures could be ascribed the following factors: (1) the highly exposed reactive (112) facets of SC-1.8 promoted carrier transport and diffusion during the PEC process and facilitated separating the electron/hole pairs and producing the predominant active species (•O2-) compared with currently used other electrodes. (2) Cationic sulfur doped on the lattice of Co3O4 can narrow the band gap to extend the photoadsorption range and improve the lifetime of •O2- to enhance the PEC efficiency. This work not only proves that the SC-1.8 architectures with highly exposed (112) facets are a promising PEC catalyst due to increasing the electron transport and the lifetime of active species but also presents a new strategy for constructing an active PEC catalyst.

Fabrication of graphene oxide wrapped Ti/Co3O4 nanowire photoanode and its superior photoelectrocatalytic performance.

Here, we successfully fabricated graphene oxide (GO) wrapped Ti/Co3O4 nanowires (NWs) by electrophoretic deposition based on the good dispersibility of GO in an aqueous solution. Interestingly, GO can adhere to the surface of Co3O4 NWs via an ultrathin gossamer-like sheet, and the coverage and wrapping of GO on the surface of Co3O4 NWs can be controlled by tuning the electrochemical deposition time and voltage. Our results also demonstrate that GO wrapped Co3O4 NWs had superior photoelectrochemical activity for the decolorization of dye (reactive brilliant blue KN-R) in wastewater, mainly because the introduction of GO can tune the oxygen evolution behavior, the transportation of reactant and induced carriers, electrochemical active areas, and the light-harvesting capability of Co3O4 NWs. Therefore, we anticipate that GO wrapped Ti/Co3O4 NWs could be considered as a promising photoanode for the treatment of organic pollutants in wastewater.

Structural characterization and anticoagulant activity of two polysaccharides from Patinopecten yessoensis viscera.

In the present study, two polysaccharides, SVP2-1 and SVP2-2, were isolated from Patinopecten yessoensis viscera and purified by using DEAE-52 cellulose and Sepharose CL-6B. Both SVP2-1 and SVP2-2 could extend activated partial thromboplastin time (APTT) and thrombin time (TT) and inhibit the transformation of fibrinogen into fibrin (FIB) concentration-dependently, indicating they inhibited clotting and thrombin through intrinsic and common pathways. Of note, SVP2-2 had stronger anticoagulant activity than SVP2-1, and its backbone was determined as →6)-α-Manp (1 → 2)-α-Galp(1 → with Xyl or Glc substituted at C4 of Gal. Based on monosaccharide composition analysis, methylation analysis, and NMR analysis. Further comparison of their monosaccharide analysis and NMR spectra indicates SVP2-1 and SVP2-2 possess the same core structure features, so the higher sulfate content and lower molecular weight may be the possible reasons for the stronger anticoagulant capability of SVP2-2. The present study suggests acidic polysaccharides from scallop viscera as promising anticoagulant candidates.

Separation and Characterization of Antioxidative and Angiotensin Converting Enzyme Inhibitory Peptide from Jellyfish Gonad Hydrolysate.

The gonad of jellyfish (RhopilemaesculentumKishinouye), containing high protein content with a rich amino acid composition, is suitable for the preparation of bioactive peptides. Jellyfish gonad was hydrolysed with neutral protease to obtain jellyfish gonad protein hydrolysate (JGPH), which was then purified sequentially by ultrafiltration, gel filtration chromatography, and RP-HPLC. The peptides were characterized with HPLC-MS/MS. One peptide with amino acid sequence Ser-Tyr (SY) was identified and synthesized, which showed good ACE inhibitory and antioxidant activity. The IC50 of this peptide on DPPH, ·OH, super oxygen anion scavenging activities, and ACE inhibitory activity are 84.623 µM, 1177.632 µM, 456.663 µM, and 1164.179 µM, respectively. The anchor in the binding site of SY and ACE C-domain (ACE-C) was obtained by molecular simulations. The results showed that the dipeptide purified from jellyfish gonad protein hydrolysates can be used as functional food material and is helpful in the study of antioxidant and inhibition of ACE.

Black TiO2 nanotube arrays fabricated by electrochemical self-doping and their photoelectrochemical performance.

Herein, black TiO2 nanotube arrays (NTAs) were fabricated using electrochemical self-doping approaches, and characterized systemically by scanning electron microscopy (SEM), powder X-ray diffraction (XRD), UV-visible absorption spectroscopy and photoluminescence spectroscopy (PL). The as-obtained black TiO2 nanotube arrays (NTAs) exhibited stronger absorption in the visible-light region, a better separation rate of light-induced carriers, and higher electrical conductivity than TiO2 nanotube arrays (NTAs). These characteristics cause black TiO2 nanotube array (NTA) electrodes to have higher photoelectrocatalytic activity for degrading anthraquinone dye (reactive brilliant blue KN-R) than the TiO2 nanotube array (NTA) electrode. Furthermore, a synergetic action between photocatalysis and electrocatalysis was also observed. The black TiO2 nanotube array (NTA) electrode is considered to be a promising photoanode for the treatment of organic pollutants.

Omics-prediction of bioactive peptides from the edible cyanobacterium Arthrospira platensis proteome.

BACKGROUND: Bioinformatics approaches are widely used to evaluate the prospects of novel protein sources in bioactive peptide research. Edible cyanobacteria are considered as potential protein precursors. However, the abundance of unicellular cyanobacterial proteins is largely unknown and highly dynamic according to the cultivation conditions, which need to be considered in this research field. The objective of this work was to evaluate the protein abundance of Arthrospira platensis, as well as to map the bioactive peptide sequences from the high-abundance proteins of the A. platensis proteome. RESULTS: The high-abundance proteins of the A. platensis proteome were identified with a high-performance liquid chromatography-tandem mass spectrometry-based method. A total of 593 proteins were detected and quantified. The occurrence frequency of the bioactive peptides in A. platensis proteome was calculated according to the amino acid sequences via the bioinformatics approaches. Further in silico digested by trypsin, pepsin and chymotrypsin, these proteins liberated 78, 99, and 96 bioactive peptides, respectively. In each case, angiotensin-converting enzyme inhibitors and dipeptidyl peptidase IV inhibitors were enriched. CONCLUSION: This work will help rationally design the protocols for cyanobacterial cultivation, protein pre-treatment and peptide separation, and further produce more peptides with specific functions. © 2017 Society of Chemical Industry.

Characteristic oligosaccharides released from acid hydrolysis for the structural analysis of chondroitin sulfate.

Because the glycosidic linkage of uronic acid is most resistant to acid, oligosaccharides may be formed during the acid hydrolysis of acidic polysaccharides. To take chondroitin sulfate (CS) as an example of acidic polysaccharides, the present study characterized the oligosaccharides released through acid hydrolysis and demonstrated their usefulness for structural confirmation. Acid hydrolysates of commercial standard CSs from shark cartilage and porcine bone were elucidated using HPLC-MSn after 1-phenyl-3-methyl-5-pyrazolone (PMP) derivatization, and altogether 11 di-, tri- and tetra-saccharides with or without sulfate/acetyl groups were identified by their multi-stage mass spectra. Meanwhile the trends of reaction yields of these oligosaccharides alone with trifluoroacetic acid (TFA) concentrations (0.1-2.0 M) were investigated, and 0.2 M TFA was recommended. Then three real samples, sturgeon backbone, porcine trachea and sea cucumber were analyzed, and their CSs were identified by detection of characteristic oligosaccharide fragments. The present study indicated that acid hydrolysis could provide information for acetyl substitution, sulfation and glycosidic linkages, and was helpful for the structural analysis of acidic polysaccharides.

Quantification and comparison of acidic polysaccharides in edible fish intestines and livers using HPLC-MS/MS.

Fish intestines and livers are usually considered as delicious and nutritious food in China. Acidic polysaccharides are important nutrients in these food of animal origin, but there is currently little information regarding their quantitative distributions. The present study demonstrated a method to quantify acidic polysaccharides simultaneously by analyzing their disaccharides produced from the acid hydrolysis using high-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry. The recoveries for these acidic polysaccharides were all 97%-115% with relative standard deviation of 3.0%-9.0%. All of the acidic polysaccharides had good linearities. Then this method was applied to determine the composition of acidic polysaccharides in 5 edible fish livers and intestines. Besides well-known glycosaminoglycans (GAGs) including hyaluronic acid (HA), Chondroitin sulfate (CS), dermatan sulfate (DS) and heparin (HP), 4 novel acidic polysaccharides including 2 GAGs and 2 non-GAGs comprised of hexose-hexuronic acid repeating units were also found. CS and HP were the major acidic polysaccharides components in fish intestines and livers, respectively. The absolute amounts of acidic polysaccharides differed greatly in these fish tissues, but their proportions showed similarity in the same type of tissues. The present study demonstrated an effective method for acidic polysaccharides quantification, and revealed acidic polysaccharides compositions of edible fish livers and intestines.