Similar Molecular Weight Research Articles

Discontinuous Atmospheric Pressure Interface in-Trap Single Photon Ionization Ion Trap Mass Spectrometry (DAPI in-Trap SPI ITMS)

A compact in-trap single photon ionization (SPI) system, termed discontinuous atmospheric pressure interface (DAPI) ion trap mass spectrometry (ITMS), for the rapid determination of trace volatile organic compounds (VOCs). DAPI enables the maintenance of high analyte pressure in the SPI source while preserving the vacuum. Utilizing vacuum ultraviolet (VUV) lamp as the ion source, we ionize the analyte within an enclosed miniature 3D ion trap for efficient analysis. Experimental findings demonstrate that the system achieves a mass resolution of less than 0.5 atomic mass units for full width at half maxima (FWHM), providing unit resolution. For the response for benzene, the system achieves almost instantaneous response, with rise and fall times of only 2 s, which is a significant advantage compared to the membrane inlet (MI) approach necessary for on-site detection. Additionally, tandem mass spectrometry (MS/MS) with unit m/z isolation window was achieved and resolved dimethyl disulfide and phenol with similar molecular weights. Our results demonstrate that the system provides excellent performance and we anticipate its application in rapidly determining VOCs.

A systematic evaluation of sample preparation and 2-D gel electrophoresis protocol for mosquito proteomic profiling

Background-Mosquito act as the carrier insect to transfer pathogens into hosts for various vector-borne diseases.To identify the pathogenesis causing determinant, comprehensive knowledge of the protein expression in different tissues and physiological conditions is very important. The most widely used technique is 2-D gel electrophoresis to study the protein expression in mosquitoes. 2-D gel electrophoresis is the multistep process to resolve intact protein with similar molecular weight. It is also useful to separate post-translational modified protein, which are not distinguished through shotgun proteomic analysis. Here, we optimized the protocol for 2-D gel electrophoresis that can effectively resolve the protein in mosquitoes and some other insects, to target immunogenic protein to fight against the vector borne disease. The optimized 2-D protocol helps to resolve complex proteomic data which is very difficult to analyze in mosquitoes.The updated protocol improved the protein solubility, resolution and visualization that help in comparative analysis of protein expression.

Structural bioinformatics studies of serotonin, dopamine and norepinephrine transporters and their AlphaFold2 predicted water-soluble QTY variants and uncovering the natural mutations of L->Q, I->T, F->Y and Q->L, T->I and Y->F.

Monoamine transporters including transporters for serotonin, dopamine, and norepinephrine play key roles in monoaminergic synaptic signaling, involving in the molecular etiology of a wide range of neurological and physiological disorders. Despite being crucial drug targets, the study of transmembrane proteins remains challenging due to their localization within the cell membrane. To address this, we present the structural bioinformatics studies of 7 monoamine transporters and their water-soluble variants designed using the QTY code, by systematically replacing the hydrophobic amino acids leucine (L), valine (V), isoleucine (I) and phenylalanine (F) with hydrophilic amino acids (glutamine (Q), threonine (T) and tyrosine (Y). The resulting QTY variants, despite significant protein transmembrane sequence differences (44.27%-51.85%), showed similar isoelectric points (pI) and molecular weights. While their hydrophobic surfaces significantly reduced, this change resulted in a minimal structural alteration. Quantitatively, Alphafold2 predicted QTY variant structures displayed remarkable similarity with RMSD 0.492Å-1.619Å. Accompanied by the structural similarities of substituted amino acids in the context of 1.5Å electron density maps, our study revealed multiple QTY and reverse QTY variations in genomic databases. We further analyzed their phenotypical and topological characteristics. By extending evolutionary game theory to the molecular foundations of biology, we provided insights into the evolutionary dynamics of chemically distinct alpha-helices, their usage in different chemotherapeutic applications, and open possibilities of diagnostic medicine. Our study rationalizes that QTY variants of monoamine transporters may not only become distinct tools for medical, structural, and evolutionary research, but these transporters may also emerge as contemporary therapeutic targets, providing a new approach to treatment for several conditions.

Observation on reversibility of flocculation in fine quartz suspensions

ABSTRACT A series of flocculation and ultrasonication tests were performed on dilute fine quartz suspensions flocculated with the use of three polyacrylamide-based flocculants of similar molecular weights but of different degrees on anionicity to investigate the reversibility of floc destruction and formation. The tests were performed as a function of ultrasonication duration and flocculant dosage. It was demonstrated that breakage of flocs did not occur down to the primary particles over the studied range of experimental conditions. Measurement of settling rate and image analysis indicated that depending on the dosage and degree of anionicity of the flocculant, broken flocs reach a steady state size following continuous breakage. In contrast to the anionic flocculants, a higher dosage of the non-ionic flocculant did not result in regrowth of larger flocs following breakage. Adsorption studies indicated that adsorption density of the polymers on mineral surface did not change as a result of breakage of flocs. A gradual increase in the size of the broken flocs was observed following ultrasonication. The results suggest that flocculation using higher than optimum dosage of anionic flocculants could facilitate regrowth of flocs following breakage.

A new hydrocolloid to rival gum Arabic: Characterisation of a traditional food gum from Australian Acacia cambagei.

This study investigated a new gum sourced from Acacia cambagei, Gidyea gum, by comparative characterisation with gum Arabic. The polysaccharide compositional analysis of Gidyea gum via Fourier transfer infrared and nuclear magnetic resonance spectroscopies was conducted, showing common structural features to gum Arabic, with minor differences in polymer branching. Microstructural imaging using transmission electron microscopy revealed the typical globular arabinogalactan glycoprotein structures of ∼10 nm diameter for both samples. Size exclusion chromatography also confirmed a similar molecular weight with 28 × 103 g mol−1 and 25 × 103 g mol−1 for Gidyea gum and gum Arabic, respectively. Gum rheological analysis determined a significantly lower apparent viscosity in the Gidyea gum. Modelling of the temporal evolution of dynamic surface and interfacial tensions revealed that Gidyea gum had a significantly lower rate of diffusion to the interfaces but similar adsorption and rearrangement rates. The dilatational viscoelastic response of Gidyea gum at the oil-water interface was consistent with gum Arabic, indicating similarities in functional performance. Indeed, Gidyea gum could stabilise orange oil-water emulsions for 15 days, exhibiting a comparable performance to those stabilised with gum Arabic. This study revealed that Gidyea gum is a functional emulsifier with the potential to be a gum Arabic alternative within the food and pharmaceutical industries.

Feasibility study on titanium‐catalyzed polyester for the preparation of high‐strength industrial yarns

AbstractIn order to overcome the environmental pollution or personal injury caused by precipitation of heavy metal ions during post‐processing and application of antimony‐catalyzed polyester industrial yarns, the titanium catalyst was used to prepare polyethylene terephthalate (PET) with high molecular weight, and then the titanium‐ catalyzed PET properties related to spinning kinetics were investigated as a basis for designing the drying, melting, spinning and extrusion, cooling, hot stretching and heat‐ setting process parameters. Compared with the spinning process of antimony‐catalyzed polyester of similar molecular weight, based on the lower melting point and melt viscosity of titanium‐catalyzed PET, the spinning temperature was lowered by about 5°C to reduce the thermal degradation of PET during extrusion, and the hot stretching speed and temperature were appropriately lowered based on the characteristics of low crystallization temperature and high crystallization rate in the heating process so that a product with a breaking strength of 8.29 cN/dtex was developed on an industrial device successfully. Titanium‐catalyzed high‐strength polyester industrial yarns, the structure and properties of crystal orientation, lamellar thickness, strength and elongation at break were comparable with those of antimony‐catalyzed polyester industrial yarns.

The effect of anionicity on mechanical degradation of polyacrylamide-type flocculants

The effect of ultrasonication, screening and shearing on five polyacrylamide-based flocculants of similar molecular weight but different degrees of anionicity (DA) was studied through measurement of intrinsic viscosity ([η]) and size exclusion chromatography (SEC) to investigate the influence of DA on the degradation of polymers. It was found that screening did not affect the [η] of the polymers while the effect of shearing was most noticeable in the cases of non-ionic and most anionic flocculants. Furthermore, ultrasonication caused a sharp decrease in the [η] which indicates a rapid degradation of the polymers. The results suggested that degradation of the polymers as a result of ultrasonication was irreversible since after a 24 hour resting period, the [η] did not recover to the values obtained for the untreated samples. Using a ratio of the [η] in distilled water to that in a dilute electrolyte as a measure of the relative flexibility of the flocculant chain, it was shown that the most flexible flocculants resisted ultrasonication and degradation better than those with rigid chains. Results from SEC confirmed that the degradation of polymers due to ultrasonication was a result of breakage of the polymer chains into sections of lower molecular weights.

Understanding of ZnO‐Catalyzed Polyurethane Synthesis from Bisurea for Further Exploration of One‐Pot Synthesis and Property Evaluation Thereof

AbstractZnO is considered to be a good catalyst for the synthesis of polyurethanes (PUs) by alcoholysis of bisureas (BUs). ZnO tends to form Zn(NCO)2(NH3)2 in the presence of urea at high temperature, so does it in the alcoholysis of BUs. Here, attempt is made to understand the role Zn(NCO)2(NH3)2 plays in the alcoholysis of BUs. A loading of Zn(NCO)2(NH3)2 at 5 mol% is found to be sufficient to catalyze the polymerization and the reaction time is greatly cut from 40 h (catalyzed by ZnO) to 26 h, with similar chemical structures and properties. The tensile strength, elongation at break, and toughness for PU–Zn‐5 can reach 43.8 MPa, 330%, and 94.0 J cm−3, respectively. One‐pot synthetic strategy is then further introduced to improve the efficiency of the polymerization. Zn(NCO)2(NH3)2, BU, and PU can be synthesized in one‐pot, by adding ZnO, urea, diamine, LiBr, and diol sequentially. The feasibility of this one‐pot method is verified, indicated by the similar reaction time, chemical structures, molecular weight, thermal and mechanical properties. This one‐pot synthetic strategy offers an efficient way to synthesize PUs directly and simply from urea, diamines, and diols, which is beneficial for improving the molecular diversity of PUs.

Pyronaridine combined with diminazene aceturate inhibits Babesia in vitro and in vivo

Objective: To evaluate the combination therapy of pyronaridine tetraphosphate and diminazene aceturate against Babesia in vitro and in vivo. Methods: Bioinformatic analysis was performed using atom pair fingerprints. An in vitro combination test was performed against Babesia bovis and Theileria equi. Moreover, the in vivo chemotherapeutic efficacy of pyronaridine tetraphosphate in combination with diminazene aceturate was investigated against the growth of Babesia microti in mice using a fluorescence inhibitory assay. Results: Pyronaridine tetraphosphate and diminazene aceturate exhibited nearly similar molecular weights. The in vitro combination of pyronaridine tetraphosphate and diminazene aceturate was synergistic on Babesia bovis and additive on Theileria equi. In addition, 5 mg/kg pyronaridine tetraphosphate combined with 10 mg/kg diminazene aceturate inhibited Babesia microti growth significantly compared with those observed after treatment with 25 mg/kg diminazene aceturate alone from day 6 post treatment to day 12 post treatment. The combination therapy also normalized the hematological parameters of infected mice. Conclusions: An oral dose of pyronaridine tetraphosphate combined with a subcutaneous dose of diminazene aceturate inhibits Babesia in vitro and in mice, suggesting it might be a new paradigm for the treatment of babesiosis.

Elucidating the effect of polyphenol-protein interactions on rheological properties of purple waxy rice

Processing purple rice causes interactions between polyphenols and protein. The effect of covalent and non-covalent interactions on the viscosity of non-pigmented (Neches) and purple (HB-1) waxy rice cultivars was studied by using dithiothreitol (DTT), urea, sodium chloride (NaCl), and acidic (pH 2) and alkaline (pH 12) environments. Urea did not affect pasting properties of both cultivars. The pasting viscosity of whole grain Neches and HB-1 and milled Neches increased by NaCl, but not that of milled HB-1. DTT reduced the pasting viscosity of Neches, whereas that of HB-1 decreased moderately. Whole grain Neches and HB-1 and milled Neches exhibited greater pasting viscosity at pH 2, whereas milled HB-1 was unaffected. Pasting viscosity of Neches was slightly affected at pH 12, whereas that of whole grain HB-1 increased and milled HB-1 decreased. Protein fractions of both cultivars shared similar molecular weight and secondary structures, but polyphenols affected the tertiary structure. The polyphenol-protein cross-links played the predominant role in the viscosity development of purple rice and may enhance the stability of the protein network at pH 2 and in the presence of DTT, but were disrupted at pH 12. Polyphenol-protein interactions may improve starch pasting properties without the need for chemical modifications.

Effect of biaxial stretching on the physical and mechanical properties of the HDPE/LDPE blend

Four different types of HDPE and LDPE were prepared, and samples (H4, L2, and L3) that exhibited similar molecular weight, melt flow index, and rheological properties as BOPE (BO) were screened. The samples were each blended, and the better compatibility of HDPE/LDPE blend system (HL1) was confirmed through the Cole-Cole plot. Thermal and thermo-mechanical properties of HL1 blend compositions were analyzed to optimize the compositions for biaxial stretching application. Especially, G′ and Tan δ were confirmed as tools to evaluate the feasibility of optimized compositions for biaxial stretching application, and the proper range of stretching temperature at which the ΔTan δ value maintained minimal energy change for biaxial stretching was determined. The modulus of the biaxially stretched samples x3 was improved by more than 10% compared to the existing sheet, and the elongation at break of all blend samples was approximately twice as good as that of BO. The better optical transparency was achieved as of biaxial stretching of blend samples, and crystal change in the stretched film compared to the sheet was clearly confirmed. From this work, it was confirmed that the G′ and Tan δ have been proved to be used as a parameter to assess the processability for biaxial stretching, and this process gave the advantage of the optimized HDPE/LDPE blend ratio with higher mechanical and optical clarity, suggesting that the blend could be applied to various packaging materials.

Joncryl chain extender reactivity with polylactide: Effect of d-lactide content, Joncryl type, and processing temperature

In this study, a highly crystallizable and an amorphous polylactide (i.e., cPLA and aPLA) with, respectively, low (0.5 mol. %) and high (12 mol. %) d-lactic acid contents and similar molecular weights were melt compounded with two different multifunctional epoxy-based Joncryl chain extenders (CEs, i.e., ADR 4400 and 4468) at 190 °C. Reactivity of Joncryl grades with aPLA was also explored at melt processing temperatures of 150, 170, and 210 °C. Small amplitude oscillatory shear rheological analysis was conducted to understand the extent of the Joncryl reaction with PLA molecules, and the results were confirmed with molecular weight determination using gel permeation chromatography. Extensional viscosity of the processed samples was also compared to control their strain hardening behavior. Results showed that the Joncryl reaction with cPLA and aPLA differs in terms of preference for chain extension or branching, indicating that molecular regularity affected the interactions with both Joncryl grades during reactive melt processing. Moreover, although the increase in processing temperature accelerated PLA degradation, it noticeably increased the reactivity of both Joncryl grades with aPLA. In all cases, ADR 4468 was more reactive in molecular chain extension/branching due to its higher functionality than ADR 4400. Differential scanning calorimetry results also revealed that the crystallization of cPLA was differently affected by the change in the Joncryl content and type.

Synthesis of Network Biobased Aliphatic Polyesters Exhibiting Better Tensile Properties than the Linear Polymers by ADMET Polymerization in the Presence of Glycerol Tris(undec-10-enoate).

Development of biobased aliphatic polyesters with better mechanical (tensile) properties in film has attracted considerable attention. This report presents the synthesis of soluble network biobased aliphatic polyesters by acyclic diene metathesis (ADMET) polymerization of bis(undec-10-enyl)isosorbide diester [M1, dianhydro-D-glucityl bis(undec-10-enoate)] in the presence of a tri-arm crosslinker [CL, glycerol tris(undec-10-enoate)] using a ruthenium-carbene catalyst, and subsequent olefin hydrogenation using RhCl(PPh3)3. The resultant polymers, after hydrogenation (expressed as HCP1) and prepared in the presence of 1.0 mol% CL, showed better tensile properties than the linear polymer (HP1) with similar molecular weight [tensile strength (elongation at break): 20.8 MPa (282%) in HP1 vs. 35.4 MPa (572%) in HCP1]. It turned out that the polymer films prepared by the addition of CL during the polymerization (expressed as a 2-step approach) showed better tensile properties. The resultant polymer film also shows better tensile properties than the conventional polyolefins such as linear high density polyethylene, polypropylene, and low density polyethylene.

Synthesis and Characterization of DOPO-Containing Poly(2,6-dimethyl-1,4-phenylene oxide)s by Oxidative Coupling Polymerization.

A set of polyphenylene oxides incorporating DOPO (9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide) functionality, denoted as DOPO-R-PPO, was synthesized by copolymerization of 2,6-dimethylphenol (2,6-DMP) with various DOPO-substituted tetramethyl bisphenol monomers. In the initial step, a Friedel-Crafts acylation reaction was employed to react 2,6-DMP with different acyl chlorides, leading to the formation of ketone derivatives substituted with 2,6-dimethylphenyl groups. Subsequently, the ketones, along with DOPO and 2,6-DMP, underwent a condensation reaction to yield a series of DOPO-substituted bisphenol derivatives. Finally, polymerizations of 2,6-dimethylphenol with these DOPO-substituted bisphenols were carried out in organic solvents using copper(I) bromide/N-butyldimethylamine catalysts (CuBr/DMBA) under a continuous flow of oxygen, yielding telechelic PPO oligomers with DOPO moieties incorporated into the polymer backbone. The chemical structures of the synthesized compounds were characterized using various analytical techniques, including Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H NMR), phosphorus nuclear magnetic resonance (31P NMR), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). When compared to conventional poly(2,6-dimethyl-1,4-phenylene oxide)s with a similar molecular weight range, all DOPO-PPOs exhibited higher glass transition temperatures, enhanced thermal degradability, and increased char yield formation at 800 °C without compromising solubility in organic solvents.

The Effect of Block Ratio and Structure on the Thermosensitivity of Double and Triple Betaine Block Copolymers.

AB-type and BAB-type betaine block copolymers composed of a carboxybetaine methacrylate and a sulfobetaine methacrylate, PGLBT-b-PSPE and PSPE-b-PGLBT-b-PSPE, respectively, were synthesized by one-pot RAFT polymerization. By optimizing the concentration of the monomer, initiator, and chain transfer agent, block extension with precise ratio control was enabled and a full conversion (~99%) of betaine monomers was achieved at each step. Two sets (total degree of polymerization: ~300 and ~600) of diblock copolymers having four different PGLBT:PSPE ratios were prepared to compare the influence of block ratio and molecular weight on the temperature-responsive behavior in aqueous solution. A turbidimetry and dynamic light scattering study revealed a shift to higher temperatures of the cloud point and micelle formation by increasing the ratio of PSPE, which exhibit upper critical solution temperature (UCST) behavior. PSPE-dominant diblocks created spherical micelles stabilized by PGLBT motifs, and the transition behavior diminished by decreasing the PSPE ratio. No particular change was found in the diblocks that had an identical AB ratio. This trend reappeared in the other set whose entire molecular weight approximately doubled, and each transition point was not recognizably impacted by the total molecular weight. For triblocks, the PSPE double ends provided a higher probability of interchain attractions and resulted in a more turbid solution at higher temperatures, compared to the diblocks which had similar block ratios and molecular weights. The intermediates assumed as network-like soft aggregates eventually rearranged to monodisperse flowerlike micelles. It is expected that the method for obtaining well-defined betaine block copolymers, as well as the relationship of the block ratio and the chain conformation to the temperature-responsive behavior, will be helpful for designing betaine-based polymeric applications.

Preparation and evaluation of in situ photocleavable mass tags with facile mass variation for matrix-free laser desorption ionization mass spectrometry.

Mass tags have been used for the precise identification, quantification, and characterization of macrobiomolecules and small organic molecules. Existing research has not yet demonstrated the preparation of a series of trityl-based photocleavable mass tags (PMTs) with similar structures but different molecular weights and mass variability. Herein, we introduce the design and synthesis of trityl-based in situ PMTs that generate heterolytic photocleavable cationic species upon laser irradiation. Mass variation of the PMTs was achieved via a simple conjugation reaction in the final step of synthesis. We prepared a series of PMTs with similar structures but different molecular weights and performed organic matrix-free laser desorption/ionization mass spectrometry (LDI MS) analysis. The practical applicability of the PMTs was evaluated by conjugating PMTs to oligonucleotides and utilizing them for detecting specific oligonucleotide targets combined with a mass signal amplification strategy. Quantitative aspects were also evaluated to verify the capability of the mass tags for multiplexed detection and the quantification of targets. The LDI MS analysis clearly demonstrated in situ heterolytic photocleavage that formed trityl cation peaks with high S/N ratios and high sensitivity. We strongly believe that the developed mass tags and LDI MS are useful alternatives to conventional signal transduction methods used for biosensors, such as surface plasmon resonance, electrochemical redox, and fluorescence.

Tautomerism and nucleophilic addition influence the performance of aqueous organic redox flow batteries of chelidamic acid and chelidonic acid

The influence of tautomerism and nucleophilic addition on chelidamic acid and chelidonic acid, compounds with similar molecular weights but different hetero atoms, was investigated in aqueous organic redox flow batteries.

Dilution-controlled deposition of mixtures of a synthetic polycation and a natural origin polyelectrolyte with anionic surfactants on negatively charged surfaces

The cosmetics industry is constantly seeking sustainable and environmentally friendly ingredients for hair care formulations to replace those traditionally derived from the petrochemical industry. In this context, the substitution of traditional cationic polyelectrolytes, such as poly(diallyldimethylammonium chloride, PDADMAC), by others of natural origin, such as chitosan, is a key challenge to achieve new formulations with a higher degree of naturality and more environmentally friendly without compromising product efficacy. This work investigates the effect of dilution on the phase separation of concentrated binary mixtures of two anionic surfactants (sodium laureth sulfate, SLES, and sodium dodecyl sulfate, SDS) with PDADMAC or chitosan. PDADMAC is a polycation of petrochemical origin, whereas chitosan is obtained from natural resources. Also, how this phase separation affects the formation of conditioning deposits on surfaces that mimic the charge and wettability of damaged hair fibers has been studied. The results show that for polymers of similar molecular weight, the substitution of PDADMAC by a highly charged chitosan is a promising alternative. The deposition is greatly enhanced for model wash formulations containing chitosan after minimal dilution. The results obtained here may pave the way to an important line of research toward improving the sustainability profile of hair care formulations without compromising consumer satisfaction.

Recyclability of Post-Consumer Polystyrene at Pilot Scale: Comparison of Mechanical and Solvent-Based Recycling Approaches.

Solvent-based and mechanical recycling technology approaches were compared with respect to each process's decontamination efficiency. Herein, post-consumer polystyrene (PS) feedstock was recycled by both technologies, yielding recycled PS resins (rPS). The process feedstock was subjected to four recycling cycles in succession to assess the technology perennity. The physico-chemical and mechanical properties of the rPS were then evaluated to discern the advantages and drawbacks of each recycling approach. The molecular weight of the mechanically recycled resin was found to decrease by 30% over the reprocessing cycles. In contrast, the solvent-base recycling technology yielded a similar molecular weight regarding the feedstock. This consistency in the rPS product is critical for consumer applications. Further qualitative and quantitative analyses on residual organic compounds and inorganic and particulate contaminants were investigated. It was found that the solvent-based technology is very efficient for purifying deeply contaminated feedstock in comparison to mechanical recycling, which is limited to well-cleaned and niche feedstocks.

An enzyme-pHBH method for specific quantification of porphyran

Porphyran, the major polysaccharide extracted from Porphyra, exhibits tremendous potential for development as functional food or pharmaceutical due to its multiple biological activities. The quantitative analysis of porphyran is important for the quality control in product development. However, the specific quantitative method of porphyran has not been established, and the lack of reference substance makes the quantification more challenging. Here, a common component of porphyran, with high purity, similar molecular weight distribution, sourced from different Porphyra producing areas in China was first prepared by a series of isolation and purification steps, and utilized as the reference substance for porphyran quantification. Subsequently, the porphyran was fully degraded into oligosaccharides by using a β-porphyranase, followed by employing para-hydroxybenzoic acid hydrazide (pHBH) method to detect the content of the generated reducing sugar. The enzyme-pHBH method for porphyran specific quantification was established. Results showed that this method was validated with good linearity, high accuracy and precision, and reliability. Addtionally, NaCl with a concentration below 0.5 %, alcohol under 8 % and other polysaccharide including chitosan, agarose, chondrotin sulfate, alginate, hyaluronic acid and κ-carrageenan did not interfere with this method. This approach is promising for quality control of the porphyran products and offers a feasible strategy for the specific quantification of other polysaccharides.