Displaying publications 81 - 98 of 98 in total

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  1. Opitz L, Lehmann S, Reichl U, Wolff MW
    Biotechnol Bioeng, 2009 Aug 15;103(6):1144-54.
    PMID: 19449393 DOI: 10.1002/bit.22345
    Strategies to control outbreaks of influenza, a contagious respiratory tract disease, are focused mainly on prophylactic vaccinations in conjunction with antiviral medications. Currently, several mammalian cell culture-based influenza vaccine production processes are being established, such as the technologies introduced by Novartis Behring (Optaflu) or Baxter International Inc. (Celvapan). Downstream processing of influenza virus vaccines from cell culture supernatant can be performed by adsorbing virions onto sulfated column chromatography beads, such as Cellufine sulfate. This study focused on the development of a sulfated cellulose membrane (SCM) chromatography unit operation to capture cell culture-derived influenza viruses. The advantages of the novel method were demonstrated for the Madin Darby canine kidney (MDCK) cell-derived influenza virus A/Puerto Rico/8/34 (H1N1). Furthermore, the SCM-adsorbers were compared directly to column-based Cellufine sulfate and commercially available cation-exchange membrane adsorbers. Sulfated cellulose membrane adsorbers showed high viral product recoveries. In addition, the SCM-capture step resulted in a higher reduction of dsDNA compared to the tested cation-exchange membrane adsorbers. The productivity of the SCM-based unit operation could be significantly improved by a 30-fold increase in volumetric flow rate during adsorption compared to the bead-based capture method. The higher flow rate even further reduced the level of contaminating dsDNA by about twofold. The reproducibility and general applicability of the developed unit operation were demonstrated for two further MDCK cell-derived influenza virus strains: A/Wisconsin/67/2005 (H3N2) and B/Malaysia/2506/2004. Overall, SCM-adsorbers represent a powerful and economically favorable alternative for influenza virus capture over conventional methods using Cellufine sulfate.
    Matched MeSH terms: Sulfates/metabolism
  2. Tao H, Bobaker AM, Ramal MM, Yaseen ZM, Hossain MS, Shahid S
    Environ Sci Pollut Res Int, 2019 Jan;26(1):923-937.
    PMID: 30421367 DOI: 10.1007/s11356-018-3663-x
    Surface and ground water resources are highly sensitive aquatic systems to contaminants due to their accessibility to multiple-point and non-point sources of pollutions. Determination of water quality variables using mathematical models instead of laboratory experiments can have venerable significance in term of the environmental prospective. In this research, application of a new developed hybrid response surface method (HRSM) which is a modified model of the existing response surface model (RSM) is proposed for the first time to predict biochemical oxygen demand (BOD) and dissolved oxygen (DO) in Euphrates River, Iraq. The model was constructed using various physical and chemical variables including water temperature (T), turbidity, power of hydrogen (pH), electrical conductivity (EC), alkalinity, calcium (Ca), chemical oxygen demand (COD), sulfate (SO4), total dissolved solids (TDS), and total suspended solids (TSS) as input attributes. The monthly water quality sampling data for the period 2004-2013 was considered for structuring the input-output pattern required for the development of the models. An advance analysis was conducted to comprehend the correlation between the predictors and predictand. The prediction performances of HRSM were compared with that of support vector regression (SVR) model which is one of the most predominate applied machine learning approaches of the state-of-the-art for water quality prediction. The results indicated a very optimistic modeling accuracy of the proposed HRSM model to predict BOD and DO. Furthermore, the results showed a robust alternative mathematical model for determining water quality particularly in a data scarce region like Iraq.
    Matched MeSH terms: Sulfates/analysis
  3. Al-Fahdawi MQ, Rasedee A, Al-Qubaisi MS, Alhassan FH, Rosli R, El Zowalaty ME, et al.
    Int J Nanomedicine, 2015;10:5739-50.
    PMID: 26425082 DOI: 10.2147/IJN.S82586
    Iron-manganese-doped sulfated zirconia nanoparticles with both Lewis and Brønsted acidic sites were prepared by a hydrothermal impregnation method followed by calcination at 650°C for 5 hours, and their cytotoxicity properties against cancer cell lines were determined. The characterization was carried out using X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy, Brauner-Emmett-Teller (BET) surface area measurements, X-ray fluorescence, X-ray photoelectron spectroscopy, zeta size potential, and transmission electron microscopy (TEM). The cytotoxicity of iron-manganese-doped sulfated zirconia nanoparticles was determined using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays against three human cancer cell lines (breast cancer MDA-MB231 cells, colon carcinoma HT29 cells, and hepatocellular carcinoma HepG2 cells) and two normal human cell lines (normal hepatocyte Chang cells and normal human umbilical vein endothelial cells [HUVECs]). The results suggest for the first time that iron-manganese-doped sulfated zirconia nanoparticles are cytotoxic to MDA-MB231 and HepG2 cancer cells but have less toxicity to HT29 and normal cells at concentrations from 7.8 μg/mL to 500 μg/mL. The morphology of the treated cells was also studied, and the results supported those from the cytotoxicity study in that the nanoparticle-treated HepG2 and MDA-MB231 cells had more dramatic changes in cell morphology than the HT29 cells. In this manner, this study provides the first evidence that iron-manganese-doped sulfated zirconia nanoparticles should be further studied for a wide range of cancer applications without detrimental effects on healthy cell functions.
    Matched MeSH terms: Sulfates/chemistry*
  4. Lai CW
    ScientificWorldJournal, 2014;2014:843587.
    PMID: 24782669 DOI: 10.1155/2014/843587
    Tungsten trioxide (WO₃) possesses a small band gap energy of 2.4-2.8 eV and is responsive to both ultraviolet and visible light irradiation including strong absorption of the solar spectrum and stable physicochemical properties. Thus, controlled growth of one-dimensional (1D) WO₃ nanotubular structures with desired length, diameter, and wall thickness has gained significant interest. In the present study, 1D WO₃ nanotubes were successfully synthesized via electrochemical anodization of tungsten (W) foil in an electrolyte composed of 1 M of sodium sulphate (Na₂SO₄) and ammonium fluoride (NH₄F). The influence of NH₄F content on the formation mechanism of anodic WO₃ nanotubular structure was investigated in detail. An optimization of fluoride ions played a critical role in controlling the chemical dissolution reaction in the interface of W/WO₃. Based on the results obtained, a minimum of 0.7 wt% of NH₄F content was required for completing transformation from W foil to WO₃ nanotubular structure with an average diameter of 85 nm and length of 250 nm within 15 min of anodization time. In this case, high aspect ratio of WO₃ nanotubular structure is preferred because larger active surface area will be provided for better photocatalytic and photoelectrochemical (PEC) reactions.
    Matched MeSH terms: Sulfates/chemistry
  5. Vasantharaja R, Stanley Abraham L, Gopinath V, Hariharan D, Smita KM
    Int J Biol Macromol, 2019 Mar 01;124:50-59.
    PMID: 30445094 DOI: 10.1016/j.ijbiomac.2018.11.104
    In this present study, isolation, characterization and protective effect of sulfated polysaccharide (SP) isolated from the brown algae Padina gymnospora was investigated. SP was isolated and characterized through FT-IR, 1H NMR, TGA, GC-MS and CHN analysis. The molecular weight of SP was found to be 16 kDa. The isolated SP contains 29.4 ± 0.35% of sulfate, 27 ± 0.11% of fucose, 0.05 ± 0.12% of protein, respectively. Furthermore, SP exhibits its excellent radical scavenging effects were evaluated by DPPH, ABTS radical scavenging and reducing power assays. Moreover, pretreatment with SP significantly mitigates H2O2 induced cytotoxicity in L-929 cells in a dose dependent manner. Furthermore, SP pretreatment ameliorates oxidative stress induced apoptosis and DNA damage, alleviates the generation of intracellular reactive oxygen species (ROS) and restores mitochondrial membrane potential (MMP) in L-929 cells through its antioxidant potential. Together, these results suggest that SP can be exploited as a natural antioxidant in the food and pharmaceutical industries.
    Matched MeSH terms: Sulfates/chemistry
  6. Prasanth VV, Puratchikody A, Mathew ST, Ashok KB
    Res Pharm Sci, 2014 Jul-Aug;9(4):259-68.
    PMID: 25657797
    The purpose of this work was to study the effect of various permeation enhancers on the permeation of salbutamol sulphate (SS) buccal patches through buccal mucosa in order to improve the bioavailability by avoiding the first pass metabolism in the liver and possibly in the gut wall and also achieve a better therapeutic effect. The influence of various permeation enhancers, such as dimethyl sulfoxide (DMSO), linoleic acid (LA), isopropyl myristate (IPM) and oleic acid (OA) on the buccal absorption of SS from buccal patches containing different polymeric combinations such as hydroxypropyl methyl cellulose (HPMC), carbopol, polyvinyl alcohol (PVA), polyvinyl pyrollidone (PVP), sodium carboxymethyl cellulose (NaCMC), acid and water soluble chitosan (CHAS and CHWS) and Eudragit-L100 (EU-L100) was investigated. OA was the most efficient permeation enhancer increasing the flux greater than 8-fold compared with patches without permeation enhancer in HPMC based buccal patches when PEG-400 was used as the plasticizer. LA also exhibited a better permeation enhancing effect of over 4-fold in PVA and HPMC based buccal patches. In PVA based patches, both OA and LA were almost equally effective in improving the SS permeation irrespective of the plasticizer used. DMSO was more effective as a permeation enhancer in HPMC based patches when PG was the plasticizer. IPM showed maximum permeation enhancement of greater than 2-fold when PG was the plasticizer in HPMC based buccal patches.
    Matched MeSH terms: Sulfates
  7. Chang SH, Teng TT, Ismail N
    J Environ Manage, 2011 Oct;92(10):2580-5.
    PMID: 21700383 DOI: 10.1016/j.jenvman.2011.05.025
    This study aimed to identify the significant factors that give large effects on the efficiency of Cu(II) extraction from aqueous solutions by soybean oil-based organic solvents using fractional factorial design. Six factors (mixing time (t), di-2-ethylhexylphosphoric acid concentration ([D2EHPA]), organic to aqueous phase ratio (O:A), sodium sulfate concentration ([Na(2)SO(4)]), equilibrium pH (pH(eq)) and tributylphosphate concentration ([TBP])) affecting the percentage extraction (%E) of Cu(II) were investigated. A 2(6-1) fractional factorial design was applied and the results were analyzed statistically. The results show that only [D2EHPA], pH(eq) and their second-order interaction ([D2EHPA] × pH(eq)) influenced the %E significantly. Regression models for %E were developed and the adequacy of the reduced model was examined. The results of this study indicate that fractional factorial design is a useful tool for screening a large number of variables and reducing the number of experiments.
    Matched MeSH terms: Sulfates
  8. Nasir Mohamad, Shariff Halim, Mohd Ekhwan Toriman, Nor Hidayah Abu Bakar, Ahmad Zubaidi A. Latif
    MyJurnal
    Zamzam is holy water believed by Muslim to have remedial power for all kinds of diseases. It contains
    many electrolytes and the concentration of the electrolytes may be affected by the types of container
    used for its storage. This study was carried out to determine the difference in ions concentration of
    Zamzam water stored in plastic and glass containers, and to determine cytotoxicity effects of Zamzam
    water against U-87 cell line (human primary glioblastoma cell line). Ion Chromatography (IC) was used
    to analyze the concentration. The analyzed anions in the Zamzam water include bromide, chloride,
    phosphate, nitrite, nitrate, sulfate and fluoride whereas the cations were ammonium, lithium, potassium,
    sodium, calcium and magnesium. Subsequently, MTT assay was used to determine the cytotoxicity of
    Zamzam water on U-87 cell line. This study reveals that Zamzam water anions and cations
    concentration was not statistically significant neither in plastic nor glass container. In addition, the
    Zamzam water did not cause any toxicity on the U87 cell line. We postulate that types of container do
    not have much influence on the ion concentration of Zamzam water and it is non-toxic on U87 cell line.
    Matched MeSH terms: Sulfates
  9. Bakhtiar A, Chowdhury EH
    Asian J Pharm Sci, 2021 Mar;16(2):236-252.
    PMID: 33995617 DOI: 10.1016/j.ajps.2020.11.002
    Genetic intervention via the delivery of functional genes such as plasmid DNA (pDNA) and short-interfering RNA (siRNA) offers a great way to treat many single or multiple genetic defects effectively, including mammary carcinoma. Delivery of naked therapeutic genes or siRNAs is, however, short-lived due to biological clearance by scavenging nucleases and circulating monocytes. Low cellular internalization of negatively-charged nucleic acids further causes low transfection or silencing activity. Development of safe and effectual gene vectors is therefore undeniably crucial to the success of nucleic acid delivery. Inorganic nanoparticles have attracted considerable attention in the recent years due to their high loading capacity and encapsulation activity. Here we introduce strontium salt-based nanoparticles, namely, strontium sulfate, strontium sulfite and strontium fluoride as new inorganic nanocarriers. Generated strontium salt particles were found to be nanosized with high affinity towards negatively-charged pDNA and siRNA. Degradation of the particles was seen with a drop in pH, suggesting their capacity to respond to pH change and undergo dissolution at endosomal pH to release the genetic materials. While the particles are relatively nontoxic towards the cells, siRNA-loaded SrF2 and SrSO3 particles exerted superior transgene expression and knockdown activity of MAPK and AKT, leading to inhibition of their phosphorylation to a distinctive extent in both MCF-7 and 4T1 cells. Strontium salt nanoparticles have thus emerged as a promising tool for applications in cancer gene therapy.
    Matched MeSH terms: Sulfates
  10. Farid Che Ghazali, Hisham Atan Edinur, Sirajudeen, K.N.S., Aroyehun, Abdul Qudus B., Shariza Abdul Razak
    MyJurnal
    Recognition of health benefits associated with consumption of marine derived biomasses is one of the most promising developments in human nutrition and disease-prevention research. This endeavor for bioactives and functional ingredients discovery from marine sources is “experience driven,” as such the search for therapeutically useful synthetic drugs, and functional components is like “looking for a needle in a haystack,” thus a daunting task. Zoonotic infection, adulteration, global warming and religious belief can be the star-gate barrier: - For example, the outsourcing for Glycosaminoglycans (GAGs), a pharmacologically bioactive compound have emerged as novel biomarkers and molecular players both within tumor cells and their microenvironment, as they integrate signals from growth factors, chemokines, integrins, and cell-cell matrix adhesion. As such, worldwide initiatives in outsourcing from geochemical signatures marine biomasses are flourishing. Most of these scientific interests are related to marketable compounds optimised via biotechnology applications. Approximately 50% of the US FDA approved drugs during 1981–2002 consist of either marine metabolites or their synthetic analogs. These bioactive compounds acts as antioxidant, peptides, chitoligosaccharides derivatives, sulfated polysaccharides, phlorotannins and carotenoids. Highlights from works to harness and provide scientific support to folk medicine much claimed legacy, pertaining to geochemical signatures vouchered sea cucumbers, macroalgae and crown of thorns starfish will be extrapolated.
    Matched MeSH terms: Sulfates
  11. Samsudin EZ, Kamarul T
    JUMMEC, 2014;17(2):1-11.
    MyJurnal
    Autologous chondrocyte implantation (ACI) is a significant technique that has gained widespread use for the treatment of focal articular cartilage damage. Since its inception in 2004, the Tissue Engineering Group (TEG) of the Faculty of Medicine, University Malaya has been dedicated to carrying out extensive research on this cell-based therapy. The objective of this report, comprising one clinical case report, six animal studies and one laboratory study, is to summarise and discuss TEG’s key findings. On the whole, we observed that the ACI technique was effective in regenerating hyaline-like cartilage in treated defects. Autologous chondrocytes and mesenchymal stem cells (MSC) were found to produce comparable tissue repair irrespective of the state of MSC differentiation, and the use of alginate-based scaffolding and oral pharmacotherapy (Glucosamine and Chondroitin Sulphate) was shown to enhance ACI-led tissue repair. ACI is suggested to be an efficient therapeutic option for the treatment of articular cartilage defects of the knee.
    Matched MeSH terms: Chondroitin Sulfates
  12. Lim, Yi-Yi, Lee, Wei-Kang, Leow, Adam Thean-Chor, Parameswari Namasivayam, Janna-Ong Abdullah, Ho, Chai-Ling
    MyJurnal
    Red seaweeds (Rhodophyta) produce a variety of sulfated galactans in their cell wall matrix and intercellular space, contributing up to 50-60 % of their total dry weight. These sulfated polysaccharides are made up of galactose disaccharides substituted with sulfate, methoxyl, pyruvic acid, or non-galactose monosaccharides (e.g. xylose, glucose and mannose). They are required by the Rhodophytes for protection against pathogen, desiccation, tidal waves and extreme changes in pH, temperature and salinity. Since ancient times, sulfated galactans from red seaweeds, such as agar and carrageenan, have been consumed as human foods and later being used in traditional medicine. Nowadays, some red seaweeds are cultivated and exploited for commercial uses in various fields. In this review, different types of sulfated galactans found in red seaweeds and their current and potential uses in food, biotechnology, medical and pharmaceutical industries are discussed.
    Matched MeSH terms: Sulfates
  13. Ahmed Atia, Nadia Salem Alrawaiq, Azman Abdullah
    Sains Malaysiana, 2018;47:2799-2809.
    Glutathione S-transferase isoenzymes (GSTs) catalyze the conjugation reaction between glutathione and electrophilic
    compounds. GSTs are involved in the detoxification of toxic and carcinogenic compounds, thus protecting the body from
    toxic injuries. Tocotrienols are part of the vitamin E family and is believed to possess potent antioxidant activity. The
    objective of this study was to determine the effect of increasing doses of tocotrienol rich fraction (TRF) supplementation
    on liver GSTs gene and protein expression. A total of 30 male ICR white mice were divided into five groups (n=6 for each
    group) and given treatment for 14 days through oral supplementation. Groups were divided as follows: - three groups
    administered with TRF at doses of 200, 500 and 1000 mg/kg, respectively, a positive control group administered with 100
    mg/kg butylated hydroxyanisole (BHA) and a control group administered with only the vehicle (corn oil). At day 15, the
    mice were sacrificed and their livers isolated. Total RNA was extracted from the liver and quantitative real-time polymerase
    chain reaction (qPCR) assays were performed to analyze GSTs gene expression. Total liver protein was also extracted
    and the protein expression of GSTs was determined by Western blotting. The results showed that TRF oral supplementation
    caused a significant dose-dependent increase in liver GST isoenzymes gene and protein expression, compared to controls.
    In conclusion, TRF oral supplementation for 14 days resulted in increased gene and protein expression of GST isoenzymes
    in mice liver dose-dependently, with the highest expression seen in mice treated with 1000 mg/kg TRF.
    Matched MeSH terms: Chondroitin Sulfates
  14. Alhassan AM, Ahmed QU, Latip J, Shah SAA
    Nat Prod Res, 2019 Jan;33(1):1-8.
    PMID: 29417849 DOI: 10.1080/14786419.2018.1437427
    The bioactivity guided fractionation of Tetracera indica leaves crude ethanolic extract has afforded the isolation and characterization of six compounds including a new natural product viz., 5,7-dihydroxyflavone-O-8-sulphate (1) and five known flavonoids (2-6). The structures of the compounds were elucidated using 1D and 2D NMR and HRESIMS spectroscopic analyses. All the isolated compounds were evaluated for their in vitro inhibitory activity against alpha-glucosidase. Compound 1, 5 and 6 showed strong alpha-glucosidase inhibitory activity, 3 and 4 displayed weak activity while compound 2 was inactive. The interactions of the active compounds with alpha-glucosidase were further investigated using molecular docking to confirm their antidiabetic potential.
    Matched MeSH terms: Sulfates
  15. Rostam MA, Kamato D, Piva TJ, Zheng W, Little PJ, Osman N
    Cell Signal, 2016 08;28(8):956-66.
    PMID: 27153775 DOI: 10.1016/j.cellsig.2016.05.002
    Hyperelongation of glycosaminoglycan chains on proteoglycans facilitates increased lipoprotein binding in the blood vessel wall and the development of atherosclerosis. Increased mRNA expression of glycosaminoglycan chain synthesizing enzymes in vivo is associated with the development of atherosclerosis. In human vascular smooth muscle, transforming growth factor-β (TGF-β) regulates glycosaminoglycan chain hyperelongation via ERK and p38 as well as Smad2 linker region (Smad2L) phosphorylation. In this study, we identified the involvement of TGF-β receptor, intracellular serine/threonine kinases and specific residues on transcription factor Smad2L that regulate glycosaminoglycan synthesizing enzymes. Of six glycosaminoglycan synthesizing enzymes, xylosyltransferase-1, chondroitin sulfate synthase-1, and chondroitin sulfotransferase-1 were regulated by TGF-β. In addition ERK, p38, PI3K and CDK were found to differentially regulate mRNA expression of each enzyme. Four individual residues in the TGF-β receptor mediator Smad2L can be phosphorylated by these kinases and in turn regulate the synthesis and activity of glycosaminoglycan synthesizing enzymes. Smad2L Thr220 was phosphorylated by CDKs and Smad2L Ser250 by ERK. p38 selectively signalled via Smad2L Ser245. Phosphorylation of Smad2L serine residues induced glycosaminoglycan synthesizing enzymes associated with glycosaminoglycan chain elongation. Phosphorylation of Smad2L Thr220 was associated with XT-1 enzyme regulation, a critical enzyme in chain initiation. These findings provide a deeper understanding of the complex signalling pathways that contribute to glycosaminoglycan chain modification that could be targeted using pharmacological agents to inhibit the development of atherosclerosis.
    Matched MeSH terms: Chondroitin Sulfates/metabolism
  16. Deng YF, Liu YY, Zhang YT, Wang Y, Liang JB, Tufarelli V, et al.
    J Sci Food Agric, 2017 Jun;97(8):2382-2391.
    PMID: 27664398 DOI: 10.1002/jsfa.8050
    BACKGROUND: The efficacy and role of inulin in the mitigation of enteric sulfur-containing odor gases hydrogen sulfide (H2 S) and methyl mercaptan (CH3 SH) in pigs were examined in this study. Twelve Duroc × Landrace × Yorkshire male finisher pigs (60.7 ± 1.9 kg), housed individually in open-circuit respiration chambers, were randomly assigned to two dietary groups, namely basal diet (control) and basal diet supplemented with 1% (w/w) inulin. At the end of the 45 day experiment, pigs were slaughtered and volatile fatty acid (VFA) concentration, sulfate radical (SO42- ) concentration, population of sulfate-reducing bacteria (SRB) and expression of methionine gamma-lyase (MGL) gene were determined in contents from the caecum, colon (two segments) and rectum. Metabonomic analysis was used to compare differences in biochemical composition, and the Illumina MiSeq procedure to investigate differences in bacterial components, in the different parts of the large intestine between inulin-supplemented and inulin-free (control) groups.

    RESULTS: Inulin decreased (P < 0.05) the average daily enteric H2 S and CH3 SH production by 12.4 and 12.1% respectively. The concentrations of acetate, propionate and butyrate in the large intestinal content were significantly increased (P < 0.05) with inulin treatment, whereas valerate concentration and MGL mRNA expression decreased (P < 0.05). The growth of Lactobacillus, Butyrivibrio, Pseudobutyrivibrio, Bifidobacterium and Clostridium butyricum was stimulated, while that of Desulfovibrio, the dominant SRB, was inhibited, and there was an accumulation of SO42- in the large intestinal content of the inulin-supplemented pigs, suggesting that inulin mitigates H2 S generation from the SO42- reduction pathway by reducing the growth of SRB.

    CONCLUSION: The results showed that inulin mitigates CH3 SH generation via three methionine degradation metabolic pathways and H2 S generation from two cysteine degradation metabolic pathways, thus resulting in increased synthesis of these two sulfur-containing amino acids in the pig large intestine. © 2016 Society of Chemical Industry.

    Matched MeSH terms: Sulfates/metabolism
  17. Dorai AA, Lim CK, Fareha AC, Halim AS
    Med J Malaysia, 2008 Jul;63 Suppl A:44.
    PMID: 19024976
    The treatment of major burn injuries are a formidable challenge to the burn surgeon. Early aggressive surgery for deep to full thickness burn injuries is vital in the prevention of infection. The ultimate goal in major burn injuries is to prevent the onset of multi-resistant organisms and achieve early wound cover. The field of tissue engineering can help to expedite the healing of these burn wounds. The development of keratinocyte culture delivery system can be used clinically to fasten the healing process and save many lives.
    Matched MeSH terms: Chondroitin Sulfates
  18. Salihu SO, Bakar NKA
    Environ Monit Assess, 2018 May 30;190(6):369.
    PMID: 29850927 DOI: 10.1007/s10661-018-6727-y
    The analysis of total organic carbon (TOC) by the American Public Health Association (APHA) closed-tube reflux colorimetric method requires potassium dichromate (K2Cr2O7), silver sulfate (AgSO4), and mercury (HgSO4) sulfate in addition to large volumes of both reagents and samples. The method relies on the release of oxygen from dichromate on heating which is consumed by carbon associated with organic compounds. The method risks environmental pollution by discharging large amounts of chromium (VI) and silver and mercury sulfates. The present method used potassium monochromate (K2CrO4) to generate the K2Cr2O7 on demand in the first phase. In addition, miniaturizing the procedure to semi microanalysis decreased the consumption of reagents and samples. In the second phase, mercury sulfate was eliminated as part of the digestion mixture through the introduction of sodium bismuthate (NaBiO3) for the removal of chlorides from the sample. The modified method, the potassium monochromate closed-tube colorimetry with sodium bismuthate chloride removal (KMCC-Bi), generates the potassium dichromate on demand and eliminates mercury sulfate. The semi microanalysis procedure leads to a 60% reduction in sample volume and ≈ 33.33 and 60% reduction in monochromate and silver sulfate consumption respectively. The LOD and LOQ were 10.17 and 33.90 mg L-1 for APHA, and 4.95 and 16.95 mg L-1 for KMCC-Bi. Recovery was between 83 to 98% APHA and 92 to 104% KMCC-Bi, while the RSD (%) ranged between 0.8 to 5.0% APHA and 0.00 to 0.62% KMCC-Bi. The method was applied for the UV-Vis spectrometry determination of COD in water and wastewater. Statistics was done by MINITAB 17 or MS Excel 2016. ᅟ Graphical abstract.
    Matched MeSH terms: Sulfates
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