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Fulltext Synthesis and Characterization of Novel Thiosalicylate-based Solid-Supported Ionic Liquid for Removal of Pb(II) Ions from Aqueous Solution

Kamaruddin NAL, Taha MF, Wilfred CD

Molecules, 2023 Jan 13;28(2).
PMID: 36677888 DOI: 10.3390/molecules28020830

The main objectives of this study are to synthesize a new solid-supported ionic liquid (SSIL) that has a covalent bond between the solid support, i.e., activated silica gel, with thiosalicylate-based ionic liquid and to evaluate the performance of this new SSIL as an extractant, labelled as Si-TS-SSIL, and to remove Pb(II) ions from an aqueous solution. In this study, 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium thiosalicylate ([MTMSPI][TS]) ionic liquid was synthesized and the formation of [MTMSPI][TS] was confirmed through structural analysis using NMR, FTIR, IC, TGA, and Karl Fischer Titration. The [MTMSPI][TS] ionic liquid was then chemically immobilized on activated silica gel to produce a new thiosalicylate-based solid-supported ionic liquid (Si-TS-SSIL). The formation of these covalent bonds on Si-TS-SSIL was confirmed by solid-state NMR analysis. Meanwhile, BET analysis was performed to study the surface area of the activated silica gel and the prepared Si-TS-SSIL (before and after washing with solvent) with the purpose to show that all physically immobilized [MTMSPI][TS] has been washed off from Si-TS-SSIL, leaving only chemically immobilized [MTMSPI][TS] on Si-TS-SSIL before proceeding with removal study. The removal study of Pb(II) ions from an aqueous solution was carried out using Si-TS-SSIL as an extractant, whereby the amount of Pb(II) ions removed was determined by AAS. In this removal study, the experiments were carried out at a fixed agitation speed (400 rpm) and fixed amount of Si-TS-SSIL (0.25 g), with different contact times ranging from 2 to 250 min at room temperature. The maximum removal capacity was found to be 8.37 mg/g. The kinetics study was well fitted with the pseudo-second order model. Meanwhile, for the isotherm study, the removal process of Pb(II) ions was well described by the Freundlich isotherm model, as this model exhibited a higher correlation coefficient (R2), i.e., 0.99, as compared to the Langmuir isotherm model.

Matched MeSH terms: Silica Gel/chemistry
Mobility Studies of (14)C-Chlorpyrifos in Malaysian Oil Palm Soils

Halimah M, Ismail BS, Nashriyah M, Maznah Z

Bull Environ Contam Toxicol, 2016 Jan;96(1):120-4.
PMID: 26546229 DOI: 10.1007/s00128-015-1685-3

The mobility of (14)C-chlorpyrifos using soil TLC was investigated in this study. It was found that chlorpyrifos was not mobile in clay, clay loam and peat soil. The mobility of (14)C-chlorpyrifos and non-labelled chlorpyrifos was also tested with silica gel TLC using three types of developing solvent hexane (100%), hexane:ethyl acetate (95:5, v/v); and hexane:ethyl acetate (98:2, v/v). The study showed that both the (14)C-labelled and non-labelled chlorpyrifos have the same Retardation Factor (Rf) for different developing solvent systems. From the soil column study on mobility of chlorpyrifos, it was observed that no chlorpyrifos residue was found below 5 cm depth in three types of soil at simulation rainfall of 20, 50 and 100 mm. Therefore, the soil column and TLC studies have shown similar findings in the mobility of chlorpyrifos.

Matched MeSH terms: Silica Gel
Advancements in the preparation and application of monolithic silica columns for efficient separation in liquid chromatography

Khoo HT, Leow CH

Talanta, 2021 Mar 01;224:121777.
PMID: 33379011 DOI: 10.1016/j.talanta.2020.121777

Fast and efficient separation remains a big challenge in high performance liquid chromatography (HPLC). The need for higher efficiency and resolution in separation is constantly in demand. To achieve that, columns developed are rapidly moving towards having smaller particle sizes and internal diameters (i.d.). However, these parameters will lead to high back-pressure in the system and will burden the pumps of the HPLC instrument. To address this limitation, monolithic columns, especially silica-based monolithic columns have been introduced. These columns are being widely investigated for fast and efficient separation of a wide range of molecules. The present article describes the current methods developed to enhance the column efficiency of particle packed columns and how silica monolithic columns can act as an alternative in overcoming the low permeability of particle packed columns. The fundamental processes behind the fabrication of the monolith including the starting materials and the silica sol-gel process will be discussed. Different monolith derivatization and end-capping processes will be further elaborated and followed by highlights of the performance such monolithic columns in key applications in different fields with various types of matrices.

Matched MeSH terms: Silica Gel
Fulltext Fuzzy-controlled humidity variation by Silica gel and Nitrogen gas in an atmospheric chamber

Ali Ghahraei, Nurul Amziah Md Yunus, Izhal Abdul Halin, Nasri Sulaiman

Pertanika Journal of Science & Technology, 2017;25(102):133-142.
MyJurnal

Controlled humidity environment is of significance in many scientific researches and experiments. In most laboratory-scale atmospheric chambers, an electrical temperature-based control system is used to adjust humidity. Since these chambers are not affordable in every laboratory, other low cost chambers using nitrogen gas or silica gel are used to adjust humidity. In this paper, a mechanism was developed to control the relative humidity in closed lab-scale chambers. Humidification is done by spraying water through a blower fan while de-humidification is by pumping air through silica gel as well as nitrogen gas injection. A Mamdani type fuzzy controller was designed to control the components and relative humidity. The results show the proposed system and controller can adjust and maintain relative humidity from 41% to 100% with maximum overshoot of 1% and the maximum range of error of steady state of 1.2 %.

Matched MeSH terms: Silica Gel
Fulltext Determination of the Major Component of Water Fraction of Katuk (Sauropus androgynous (L.) Merr.) Leaves by Liquid Chromatography-Mass Spectrometry

Mustarichie R, Salsabila T, Iskandar Y

J Pharm Bioallied Sci, 2019 Dec;11(Suppl 4):S611-S618.
PMID: 32148372 DOI: 10.4103/jpbs.JPBS_205_19

Background: The katuk leaf (Sauropus androgynous (L.) Merr.) is one of the plants that are used to overcome baldness by the people of Kampung Mak Kemas, Malaysia. It is suspected that secondary metabolites contained in katuk leaves play a key role in stimulating hair growth.
Aims and Objectives: The aim of this study was to identify the optimum method to obtain one of the chemical compounds in the water fraction and to identify the hypothesized chemical isolates in the water fraction katuk leave's ethanol extract.
Materials and Methods: The methods used in this study included the collection and determination of the katuk plant, the processing of the katuk, phytochemical filtrating, extracting with ethanol 96%, and fractionation using the liquid-liquid extraction method with n-hexane, ethyl acetate, and water solvents The water fraction of katuk leaves was analyzed by its components by thin-layer chromatography using the stationary phase of silica gel 60 F254, developer of n-butanol:acetic acid:water (4:1:5), and detection under ultraviolet (UV) light at a wavelength of 366 and 254nm, as well as with vanillin-sulfuric acid reagent. To isolate the compounds from water fraction of katuk leaves, it was then eluted with a vacuum column chromatography by eluent with a level polarity that would get 11 subfractions. Each subfraction was checked by two-dimensional thin-layer chromatography to see subfraction purity characterized by the appearance of a spot on the chromatogram plate. The isolate was analyzed using spot test, ultraviolet-visible spectrophotometer, infrared spectrophotometer, and liquid chromatography-mass spectrometry.
Results: The isolate was an alkaloid compound with a molecular mass of 406.3131 m/z with the molecular formula C21H39N6O2 as S, S-5, 5'-amino-4,4'-dihexyl-propyldihydropyrazol-3, 3-one.
Conclusion: One of the chemical compounds contained in the water fraction of the ethanol extract of the katuk leaf was an alkaloid group.

Matched MeSH terms: Silica Gel
Selective magnetic mercury(ii) ion capturing ligand-doped silica gel for water analysis

Khor SW, Lee YK, Tay KS

Analyst, 2019 Mar 21;144(6):1968-1974.
PMID: 30694266 DOI: 10.1039/c8an02362j

Preparation of selective magnetic adsorbents for dispersive micro-solid phase extraction often involves multi-step reactions which are time consuming. This study demonstrates a simplified method for the synthesis of a magnetic adsorbent, which is selective towards the adsorption of mercury(ii) ions (Hg2+). In this method, the incorporation of a metal capturing ligand (3-oxo-1,3-diphenylpropyl-2-(naphthalen-2-ylamino) ethylcarbamodithioate) and the coating of magnetic particles with silica gel was performed in a single step. This adsorbent was then used in solid-phase microextraction for the preconcentration of Hg2+ in water. In this study, a mercury analyzer was used to quantify the Hg2+. Under optimized conditions, the developed analytical method achieved a low detection limit (4.0 ng L-1), satisfactory enrichment factor (96.4) and wide linearity range (50.0-5000 ng L-1) with a good coefficient of determination (0.9985) and good repeatability (<7%). The preconcentration factor of this method was 100. This proposed method was also successfully utilized for the determination of Hg2+ in drinking water, tap water and surface water with good recovery (>91%) and high intra-day and inter-day precision.

Matched MeSH terms: Silica Gel
Fulltext A large response range reflectometric urea biosensor made from silica-gel nanoparticles

Alqasaimeh M, Heng LY, Ahmad M, Raj AS, Ling TL

Sensors (Basel), 2014 Jul 22;14(7):13186-209.
PMID: 25054632 DOI: 10.3390/s140713186

A new silica-gel nanospheres (SiO2NPs) composition was formulated, followed by biochemical surface functionalization to examine its potential in urea biosensor development. The SiO2NPs were basically synthesized based on sol-gel chemistry using a modified Stober method. The SiO2NPs surfaces were modified with amine (-NH2) functional groups for urease immobilization in the presence of glutaric acid (GA) cross-linker. The chromoionophore pH-sensitive dye ETH 5294 was physically adsorbed on the functionalized SiO2NPs as pH transducer. The immobilized urease determined urea concentration reflectometrically based on the colour change of the immobilized chromoionophore as a result of the enzymatic hydrolysis of urea. The pH changes on the biosensor due to the catalytic enzyme reaction of immobilized urease were found to correlate with the urea concentrations over a linear response range of 50-500 mM (R2 = 0.96) with a detection limit of 10 mM urea. The biosensor response time was 9 min with reproducibility of less than 10% relative standard deviation (RSD). This optical urea biosensor did not show interferences by Na+, K+, Mg2+ and NH4+ ions. The biosensor performance has been validated using urine samples in comparison with a non-enzymatic method based on the use of p-dimethylaminobenzaldehyde (DMAB) reagent and demonstrated a good correlation between the two different methods (R2 = 0.996 and regression slope of 1.0307). The SiO2NPs-based reflectometric urea biosensor showed improved dynamic linear response range when compared to other nanoparticle-based optical urea biosensors.

Matched MeSH terms: Silica Gel/chemistry*
Characteristics of supported nano-TiO2/ZSM-5/silica gel (SNTZS): photocatalytic degradation of phenol

Zainudin NF, Abdullah AZ, Mohamed AR

J Hazard Mater, 2010 Feb 15;174(1-3):299-306.
PMID: 19818556 DOI: 10.1016/j.jhazmat.2009.09.051

Photocatalytic degradation of phenol was investigated using the supported nano-TiO(2)/ZSM-5/silica gel (SNTZS) as a photocatalyst in a batch reactor. The prepared photocatalyst was characterized using XRD, TEM, FT-IR and BET surface area analysis. The synthesized photocatalyst composition was developed using nano-TiO(2) as the photoactive component and zeolite (ZSM-5) as the adsorbents, all supported on silica gel using colloidal silica gel binder. The optimum formulation of SNTZS catalyst was observed to be (nano-TiO(2):ZSM-5:silica gel:colloidal silica gel=1:0.6:0.6:1) which giving about 90% degradation of 50mg/L phenol solution in 180 min. The SNTZS exhibited higher photocatalytic activity than that of the commercial Degussa P25 which only gave 67% degradation. Its high photocatalytic activity was due to its large specific surface area (275.7 m(2)/g), small particle size (8.1 nm), high crystalline quality of the synthesized catalyst and low electron-hole pairs recombination rate as ZSM-5 adsorbent was used. The SNTZS photocatalyst synthesized in this study also has been proven to have an excellent adhesion and reusability.

Matched MeSH terms: Silica Gel
Effect of magnetic field on nano-magnetite composite exhibits in ion-adsorption

Lo FF, Kow KW, Kung F, Ahamed F, Kiew PL, Yeap SP, et al.

Sci Total Environ, 2021 Aug 01;780:146337.
PMID: 33770606 DOI: 10.1016/j.scitotenv.2021.146337

Nano-magnetites are widely researched for its potential as an excellent adsorbent in many applications. However, the efficiency of the nano-magnetites are hindered by their tendency to agglomerate. In this work, we dispersed and embedded the nano-magnetites in a porous silica gel matrix to form a nanocomposite to reduce the extent of agglomeration and to enhance the adsorption performance. Our experimental results showed that the removal efficiency of Cu2+ ion has improved by 46% (22.4 ± 2.2%) on the nano-magnetite-silica-gel (NMSG) nanocomposite as compared to pure nano-magnetites (15.3 ± 0.6%). The adsorption capacity is further enhanced by 39% (from 11.2 ± 1.1 to 15.6 ± 1.6 mg/g) by subjecting the NMSG to a magnetic field prior to adsorption. We infer that the magnetic field aligned the magnetic domains within the nano-magnetites, resulting in an increased Lorentz force during adsorption. Similar alignment of magnetic domains is near to impossible in pure nano-magnetites due to severe agglomeration. We further found that the adsorption capacity of the NMSG can be manipulated with an external magnetic field by varying the strength and the configurations of the field. Equipped with proper process design, our finding has great potentials in processes that involve ion-adsorptions, for example, NMSG can: (i) replace/reduce chemical dosing in controlling adsorption kinetics, (ii) replace/reduce complex chemicals required in ion-chromatography columns, and (iii) reduce wastage of nano-adsorbents by immobilizing it in a porous matrix.

Matched MeSH terms: Silica Gel
Fulltext Antimicrobial activity and chemical composition of Pistacia chinensis Bunge leaves

Rashed, K., Said, A., Abdo, A., Selim, S.

International Food Research Journal, 2016;23(1):316-321.
MyJurnal

This work was carried out for determining antimicrobial activity of Pistacia chinensis leaves
methanol extract and identifying the chemical composition of the plant extract. Methanol extract
was tested for antimicrobial activity using disc-diffusion assay and the extract was fractionated
on silica gel column chromatography for the isolation of the bio-active constituents. The leaves
extract of P. chinensis showed a significant antimicrobial effect, it strongly inhibited the growth
of the test bacteria and yeast studied. Chromatograpic separation of the methanol extract of
P. chinensis leaves has led to the isolation and characterization of β-sitosterol, luepol, and
six flavonoids, quercetin, myricetin, quercetin 3-O-α-rhamnoside, quercetin 3-O-β-glucoside,
myricetin 3-O-α-rhamnoside and myricetin 3-O-β-glucuronide using various chromatographic
procedures and the interpretation of spectral data in comparison with already existing data
reported in the literature. The results presented here may suggest that the leaves extract of P.
chinensis possess antimicrobial properties, and therefore, can be used as natural preservative
ingredients in food and/or pharmaceuticals.

Matched MeSH terms: Silica Gel
Fulltext Distributions, composition patterns, sources and potential toxicity of Polycyclic Aromatic Hydrocarbons (PAHs) pollution in surface sediments from the Kim Kim River and Segget River, Peninsula Malaysia

Keshavarzifard, Mehrzad, Mohamad Pauzi Zakaria, Keshavarzifard, Shahin, Sharifi, Reza

Pertanika Journal of Science & Technology, 2018;26(1):95-120.
MyJurnal

This study investigated distributions, composition patterns, sources and potential toxicity of polycyclic aromatic hydrocarbon (PAHs) pollution in surface sediments from the Kim Kim River and Segget River, Peninsular Malaysia. The samples were extracted using Soxhlet extraction, purified using two-step silica gel column chromatography and then analysed by gas chromatography mass spectrometry (GC-MS). The total PAH concentrations ranged from 95.17 to 361.24 ng g-1 dry weight (dw) and 330.09 to 552.76 ng g-1 dw in surface sediments from the Kim Kim and Segget Rivers, respectively. Source type identification using PAH molecular indices and hierarchical cluster analysis (HCA) indicated that PAHs were mostly of pyrogenic origin, while in some stations petrogenic sources had a significant portion. A PAH toxicity assessment using sediment quality guidelines (SQGs), mean effect range-median quotient (M-ERM-Q), benzo[a]pyrene (BaP) equivalent concentration and BaP toxicity equivalent quotient (TEQcarc) indicated low probability of toxicity for both the Kim Kim and Segget Rivers. Moreover, the human health risk assessment applying Cancer Riskingestion and Cancer Riskdermal indicated that probabilistic health risk to humans via ingestion and dermal pathways from sediments of the Kim Kim and Segget Rivers can be categorised as low-to-moderate risk.

Matched MeSH terms: Silica Gel
Cryopreservation of whole seeds and excised embryonic axes of Citrus suhuiensis cv. limau langkat in accordance to their desiccation sensitivity

Makeen MA, Noor NM, Dussert S, Clyde MM

Cryo Letters, 2005 Jul-Aug;26(4):259-68.
PMID: 19827255

Following the investigation of desiccation sensitivity and freezing tolerance of the whole seed of Citrus suhuiensis cv. limau langkat, desiccation sensitivity and cryopreservation of the excised embryonic axes from the seeds of the same species were examined. Three drying conditions were employed: desiccation by equilibrium for the whole seeds and desiccation in laminar airflow and over silica gel for the excised embryonic axes. The relevance of desiccation sensitivity (WC50) to cryopreservation of whole seeds and excised axes was investigated. High desiccation tolerance (WC50 = 0.034 g H2O x g(-1)dw) was acquired for axes desiccated with faster dehydration rate (1.5 g x g(-1) x h(-1)) in laminar airflow compared to substantially lower desiccation tolerance (WC50 = 0.132 and 0.110 g H2O x g(-1)dw) acquired under slower dehydration rates (1.0 and 0.005 g x g(-1) x h(-1)) for axes desiccated over silica gel and whole seeds desiccated by equilibrium respectively. While few whole seeds (8.3%) survived freezing, high recovery percentages of axes (83.3% and 62.2%) after freezing were obtained under laminar airflow and silica gel drying conditions respectively. Irrespective of the drying method employed, axes survival percentages after exposure to LN temperature commensurate with the desiccation sensitivity pattern. For the whole seeds, a factor other than desiccation sensitivity that limits the tolerance to exposure to LN temperature seems to exist and still needs to be defined.

Matched MeSH terms: Silica Gel
In vitro cytotoxicity of Clinacanthus nutans fractions on breast cancer cells and molecular docking study of sulphur containing compounds against caspase-3

Mutazah R, Hamid HA, Mazila Ramli AN, Fasihi Mohd Aluwi MF, Yusoff MM

Food Chem Toxicol, 2019 Oct 15.
PMID: 31626839 DOI: 10.1016/j.fct.2019.110869

Clinacanthus nutans has attracted Malaysian public interest due to its high medicinal value in the prevention of cancer. Currently, the specific compound or compounds giving rise to the anticancer potential of C. nutans has not been investigated thoroughly. The extraction was carried out by MeOH at room temperature using the powdered bark of C. nutans, while chromatography was carried out on a silica gel RP-18 column using the crude methanolic extract. Six fractions collected from column chromatography were evaluated by MTT assay against two breast cancer cell lines: MDA-MB-231 and MCF-7. Amongst the fractions, A12 and A17 were shown to exhibit the highest activity. Two sulphur-containing compounds, viz., entadamide C (1) and clinamide D (2), were isolated from these fractions. Molecular docking simulation studies revealed that entadamide C and clinamide D could bind favourably to the caspase-3 binding site with the binding energy of -4.28 kcal/mol and -4.84 kcal/mol, respectively. This study provides empirical evidence for the presence of sulphur-containing compounds in the leaves of C. nutans that displayed anticancer effects which explains its ethnomedicinal application against breast cancer. The docking simulation study showed that both compounds could serve as important templates for future drug design and development.

Matched MeSH terms: Silica Gel
Green Synthesis, Antioxidant, and Plant Growth Regulatory Activities of Novel α-Furfuryl-2-alkylaminophosphonates

Nadiveedhi MR, Nuthalapati P, Gundluru M, Yanamula MR, Kallimakula SV, Pasupuleti VR, et al.

ACS Omega, 2021 Feb 02;6(4):2934-2948.
PMID: 33553912 DOI: 10.1021/acsomega.0c05302

A series of novel α-furfuryl-2-alkylaminophosphonates have been efficiently synthesized from the one-pot three-component classical Kabachnik-Fields reaction in a green chemical approach by addition of an in situ generated dialkylphosphite to Schiff's base of aldehydes and amines by using environmental and eco-friendly silica gel supported iodine as a catalyst by microwave irradiation. The advantage of this protocol is simplicity in experimental procedures and products were resulted in high isolated yields. The synthesized α-furfuryl-2-alkylaminophosphonates were screened to in vitro antioxidant and plant growth regulatory activities and some are found to be potent with antioxidant and plant growth regulatory activities. These in vitro studies have been further supported by ADMET (absorption, distribution, metabolism, excretion, and toxicity), quantitative structure-activity relationship, molecular docking, and bioactivity studies and identified that they were potentially bound to the GLN340 amino acid residue in chain C of 1DNU protein and TYR597 amino acid residue in chain A of 4M7E protein, causing potential exhibition of antioxidant and plant growth regulatory activities. Eventually, title compounds are identified as good blood-brain barrier (BBB)-penetrable compounds and are considered as proficient central nervous system active and neuroprotective antioxidant agents as the neuroprotective property is determined with BBB penetration thresholds.

Matched MeSH terms: Silica Gel
Fulltext Chemical constituents of the insecticidal active extract of Tinospora crispa

Nor Aziyah Bakhari, Siti Nur Amirah Diana Fadzillah, Norain Isa

Scientific Research Journal, 2013;10(1):0-0.
MyJurnal

Tinospora crispa Miers (Menispermaceae) is a climbing vine with stems rich in warts. The plant is called Akar Seruntum or Patawali in Malaysia and is widely used for treating skin complaints, malaria, bacterial abscess, high blood pressure and diabetes. In the present study, the stems of T. crispa were collected from the locality and succesively extracted with petroleum ether, followed by chloroform and ethanol. The insecticidal active extract (ethanol extract) was subjected to column chromatography of silica gel eluted with a gradient mobile phase containing hexane, chloroform and ethanol. Among the chemical constituents isolated are n-tetracosyl trans-ferulate and n-octacosyl alcohol, along with three known aporphine alkaloids; N-formylnornuciferine, N-acetylnornuciferine and lysicamine. All compounds were identified by comparing their spectroscopic data (UV, IR, 1H NMR, MS) with data from corresponding values in the literature. Isolation of n-tetracosyl trans-ferulate and noctacosyl alcohol is reported the first time for T. crispa.

Matched MeSH terms: Silica Gel
Fulltext Enzymatic synthesis of polyphenol glycosides catalyzed by transglycosylation reaction of cyclodextrin glucanotransferase derived from Trichoderma viride

Nazir S, Sulistyo J, Hashmi MI, Ho AL, Khan MS

J Food Sci Technol, 2018 Aug;55(8):3026-3034.
PMID: 30065412 DOI: 10.1007/s13197-018-3223-x

Present study was conducted to evaluate the ability of Trichoderma viride as a source of cyclodextrin glucanotransferase that has shown transglycosylation activity in the presence of polyphenolic constituents extracted from Moringa oleifera leaves as its acceptor and wheat flour as its substrate to catalyze synthesis of polyphenolic glycosides as transglycosylation (transfer) reaction products. The enzymatic synthesized polyphenolic glycosides were then purified using octa-dodecyl-functionalized silica gel column chromatography prior to analysis using thin layer chromatography and high performance liquid chromatography and identified using nuclear magnetic resonance (NMR) spectroscopy. The high performance liquid chromatogram performed that the isolated transglycosylation products had retention times and concentration at 1.446 min (0.0017 mg/ml), 1.431 min (0.14 mg/ml), and 1.474 min (0.012 mg/ml), respectively, compared to the retention time of arbutin (1.474 min) that was applied as authentic standard for polyphenol glycoside. Moreover, observation using 1H NMR as well as 13C NMR showed that structures of the transglycosylation products were identified as gallic acid-4-O-β-glucopyranoside, ellagicacid-4-O-β-glucopyranoside, and catechin-4'-O-glucopyranoside, respectively.

Matched MeSH terms: Silica Gel

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