Displaying publications 1 - 20 of 24 in total

  1. Karim AH, Jalil AA, Triwahyono S, Sidik SM, Kamarudin NH, Jusoh R, et al.
    J Colloid Interface Sci, 2012 Nov 15;386(1):307-14.
    PMID: 22889626 DOI: 10.1016/j.jcis.2012.07.043
    In this work, mesostructured silica nanoparticles (MSN(AP)) with high adsorptivity were prepared by a modification with 3-aminopropyl triethoxysilane (APTES) as a pore expander. The performance of the MSN(AP) was tested by the adsorption of MB in a batch system under varying pH (2-11), adsorbent dosage (0.1-0.5 g L(-1)), and initial MB concentration (5-60 mg L(-1)). The best conditions were achieved at pH 7 when using 0.1 g L(-1) MSN(AP) and 60 mg L(-1)MB to give a maximum monolayer adsorption capacity of 500.1 mg g(-1) at 303 K. The equilibrium data were evaluated using the Langmuir, Freundlich, Temkin, and Harkins-Jura isotherms and fit well to the Freundlich isotherm model. The adsorption kinetics was best described by the pseudo-second order model. The results indicate the potential for a new use of mesostructured materials as an effective adsorbent for MB.
    Matched MeSH terms: Silanes/chemistry*
  2. Ang QY, Low SC
    Anal Bioanal Chem, 2015 Sep;407(22):6747-58.
    PMID: 26163132 DOI: 10.1007/s00216-015-8841-9
    Molecular imprinting is an emerging technique to create imprinted polymers that can be applied in affinity-based separation, in particular, biomimetic sensors. In this study, the matrix of siloxane bonds prepared from the polycondensation of hydrolyzed tetraethoxysilane (TEOS) was employed as the inorganic monomer for the formation of a creatinine (Cre)-based molecularly imprinted polymer (MIP). Doped aluminium ion (Al(3+)) was used as the functional cross-linker that generated Lewis acid sites in the confined silica matrix to interact with Cre via sharing of lone pair electrons. Surface morphologies and pore characteristics of the synthesized MIP were determined by field emission scanning electron microscopy (FESEM) and Brunauer-Emmet-Teller (BET) analyses, respectively. The imprinting efficiency of MIPs was then evaluated through the adsorption of Cre with regard to molar ratios of Al(3+). A Cre adsorption capacity of up to 17.40 mg Cre g(-1) MIP was obtained and adsorption selectivity of Cre to its analogues creatine (Cr) and N-hydroxysuccinimide (N-hyd) were found to be 3.90 ± 0.61 and 4.17 ± 3.09, respectively. Of all the studied MIP systems, chemisorption was predicted as the rate-limiting step in the binding of Cre. The pseudo-second-order chemical reaction kinetic provides the best correlation of the experimental data. Furthermore, the equilibrium adsorption capacity of MIP fit well with a Freundlich isotherm (R (2) = 0.98) in which the heterogeneous surface was defined.
    Matched MeSH terms: Silanes/chemistry*
  3. Oyekanmi AA, Saharudin NI, Hazwan CM, H P S AK, Olaiya NG, Abdullah CK, et al.
    Molecules, 2021 Apr 13;26(8).
    PMID: 33924692 DOI: 10.3390/molecules26082254
    Hydrophilic behaviour of carrageenan macroalgae biopolymer, due to hydroxyl groups, has limited its applications, especially for packaging. In this study, macroalgae were reinforced with cellulose nanofibrils (CNFs) isolated from kenaf bast fibres. The macroalgae CNF film was after that treated with silane for hydrophobicity enhancement. The wettability and functional properties of unmodified macroalgae CNF films were compared with silane-modified macroalgae CNF films. Characterisation of the unmodified and modified biopolymers films was investigated. The atomic force microscope (AFM), SEM morphology, tensile properties, water contact angle, and thermal behaviour of the biofilms showed that the incorporation of Kenaf bast CNF remarkably increased the strength, moisture resistance, and thermal stability of the macroalgae biopolymer films. Moreover, the films' modification using a silane coupling agent further enhanced the strength and thermal stability of the films apart from improved water-resistance of the biopolymer films compared to unmodified films. The morphology and AFM showed good interfacial interaction of the components of the biopolymer films. The modified biopolymer films exhibited significantly improved hydrophobic properties compared to the unmodified films due to the enhanced dispersion resulting from the silane treatment. The improved biopolymer films can potentially be utilised as packaging materials.
    Matched MeSH terms: Silanes/chemistry*
  4. Ullah F, Othman MB, Javed F, Ahmad Z, Akil HM, Rasib SZ
    Int J Biol Macromol, 2016 Feb;83:376-84.
    PMID: 26597568 DOI: 10.1016/j.ijbiomac.2015.11.040
    A new approach to design multifunctional chitosan based nanohydrogel with enhanced glucose sensitivity, stability, drug loading and release profile are reported. Two approaches were followed for functionalization of chitosan based nanohydrogel with 3-APBA via EDC and 3-APTES. The effective functionalization, structure and morphology of Chitosan based IPN respectively were confirmed by FTIR, SEM and AFM. At physiological conditions, the glucose-induced volume phase transition and release profile of the model drug Alizarin Red with 1,2-diol structure (comparative to insulin as a drug as well as a dye for bio separation) were studied at various glucose concentrations, pH and ionic strengths. The results suggested a new concept for diabetes treatment and diols sensitivity in view of their potential hi-tech applications in self-regulated on-off response to the treatment (drug delivery and bio separation concurrently).
    Matched MeSH terms: Silanes/chemistry
  5. Yung LC, Fei CC, Mandeep J, Binti Abdullah H, Wee LK
    PLoS One, 2014;9(5):e97484.
    PMID: 24830317 DOI: 10.1371/journal.pone.0097484
    The success of printing technology in the electronics industry primarily depends on the availability of metal printing ink. Various types of commercially available metal ink are widely used in different industries such as the solar cell, radio frequency identification (RFID) and light emitting diode (LED) industries, with limited usage in semiconductor packaging. The use of printed ink in semiconductor IC packaging is limited by several factors such as poor electrical performance and mechanical strength. Poor adhesion of the printed metal track to the epoxy molding compound is another critical factor that has caused a decline in interest in the application of printing technology to the semiconductor industry. In this study, two different groups of adhesion promoters, based on metal and polymer groups, were used to promote adhesion between the printed ink and the epoxy molding substrate. The experimental data show that silver ink with a metal oxide adhesion promoter adheres better than silver ink with a polymer adhesion promoter. This result can be explained by the hydroxyl bonding between the metal oxide promoter and the silane grouping agent on the epoxy substrate, which contributes a greater adhesion strength compared to the polymer adhesion promoter. Hypotheses of the physical and chemical functions of both adhesion promoters are described in detail.
    Matched MeSH terms: Silanes/chemistry
  6. Omar MM, Wan Ibrahim WA, Elbashir AA
    Food Chem, 2014 Sep 1;158:302-9.
    PMID: 24731346 DOI: 10.1016/j.foodchem.2014.02.045
    A sol-gel hybrid sorbent, methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was successfully used as new dispersive solid phase extraction (dSPE) sorbent material in the determination of acrylamide in several Sudanese foods and analysis using GC-MS. Several important dSPE parameters were optimised. Under the optimised conditions, excellent linearity (r(2)>0.9998) was achieved using matrix matched standard calibration in the concentration range 50-1000 μg kg(-1). The limits of detection (LOD) and limit of quantification ranged from 9.1 to 12.8 μg/kg and 27.8-38.9 μg/kg, respectively. The precision (RSD%) of the method was ⩽6.6% and recoveries of acrylamide obtained were in the range of 88-103%, (n=3). The LOD obtained is comparable with the LODs of primary secondary amine dSPE. The proposed MTMOS-TEOS dSPE method is direct and safe for acrylamide analysis, showed reliable method validation performances and good cleanup effects. It was successfully applied to the analysis of acrylamide in real food samples.
    Matched MeSH terms: Silanes/chemistry
  7. Ahmad MB, Gharayebi Y, Salit MS, Hussein MZ, Ebrahimiasl S, Dehzangi A
    Int J Mol Sci, 2012;13(4):4860-72.
    PMID: 22606014 DOI: 10.3390/ijms13044860
    Polyimide/SiO(2) composite films were prepared from tetraethoxysilane (TEOS) and poly(amic acid) (PAA) based on aromatic diamine (4-aminophenyl sulfone) (4-APS) and aromatic dianhydride (3,3,4,4-benzophenonetetracarboxylic dianhydride) (BTDA) via a sol-gel process in N-methyl-2-pyrrolidinone (NMP). The prepared polyimide/SiO(2) composite films were characterized using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and thermogravimetric analysis (TGA). The FTIR results confirmed the synthesis of polyimide (4-APS/BTDA) and the formation of SiO(2) particles in the polyimide matrix. Meanwhile, the SEM images showed that the SiO(2) particles were well dispersed in the polyimide matrix. Thermal stability and kinetic parameters of the degradation processes for the prepared polyimide/SiO(2) composite films were investigated using TGA in N(2) atmosphere. The activation energy of the solid-state process was calculated using Flynn-Wall-Ozawa's method without the knowledge of the reaction mechanism. The results indicated that thermal stability and the values of the calculated activation energies increased with the increase of the TEOS loading and the activation energy also varied with the percentage of weight loss for all compositions.
    Matched MeSH terms: Silanes/chemistry
  8. Vakili M, Rafatullah M, Salamatinia B, Ibrahim MH, Abdullah AZ
    Carbohydr Polym, 2015 Nov 05;132:89-96.
    PMID: 26256328 DOI: 10.1016/j.carbpol.2015.05.080
    The adsorption behavior of chitosan (CS) beads modified with 3-aminopropyl triethoxysilane (APTES) for the removal of reactive blue 4 (RB4) in batch studies has been investigated. The effects of modification conditions, such as the APTES concentration, temperature and reaction time on RB4 removal, were studied. The adsorbent prepared at a concentration of 2 wt% APTES for 8h at 50 °C was the most effective one for RB4 adsorption. The adsorption capacity of modified CS beads (433.77 mg/g) was 1.37 times higher than that of unmodified CS beads (317.23 mg/g). The isotherm data are adequately described by a Freundlich model, and the kinetic study revealed that the pseudo-second-order rate model was in better agreement with the experimental data. The negative values of the thermodynamic parameters, including ΔG° (-2.28 and -4.70 kJ/mol at 30 ± 2 °C), ΔH° (-172.18 and -43.82 kJ/mol) and ΔS° (-560.71 and -129.08 J/mol K) for CS beads and APTES modified beads, respectively, suggest that RB4 adsorption is a spontaneous and exothermic process.
    Matched MeSH terms: Silanes/chemistry*
  9. Daood U, Gopinath D, Pichika MR, Mak KK, Seow LL
    Molecules, 2021 Apr 12;26(8).
    PMID: 33921378 DOI: 10.3390/molecules26082214
    To determine whether quaternary ammonium (k21) binds to Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) spike protein via computational molecular docking simulations, the crystal structure of the SARS-CoV-2 spike receptor-binding domain complexed with ACE-2 (PDB ID: 6LZG) was downloaded from RCSB PD and prepared using Schrodinger 2019-4. The entry of SARS-CoV-2 inside humans is through lung tissues with a pH of 7.38-7.42. A two-dimensional structure of k-21 was drawn using the 2D-sketcher of Maestro 12.2 and trimmed of C18 alkyl chains from all four arms with the assumption that the core moiety k-21 was without C18. The immunogenic potential of k21/QA was conducted using the C-ImmSim server for a position-specific scoring matrix analyzing the human host immune system response. Therapeutic probability was shown using prediction models with negative and positive control drugs. Negative scores show that the binding of a quaternary ammonium compound with the spike protein's binding site is favorable. The drug molecule has a large Root Mean Square Deviation fluctuation due to the less complex geometry of the drug molecule, which is suggestive of a profound impact on the regular geometry of a viral protein. There is high concentration of Immunoglobulin M/Immunoglobulin G, which is concomitant of virus reduction. The proposed drug formulation based on quaternary ammonium to characterize affinity to the SARS-CoV-2 spike protein using simulation and computational immunological methods has shown promising findings.
    Matched MeSH terms: Silanes/chemistry
  10. Veloo KV, Ibrahim NAS
    J Sep Sci, 2020 Aug;43(15):3027-3035.
    PMID: 32386268 DOI: 10.1002/jssc.201901237
    A new sol-gel hybrid methyltrimethoxysilane-chloropropyltriethoxysilane was prepared as sorbent for solid-phase extraction. The extraction efficiency of the prepared sol-gel hybrid methyltrimethoxysilane-chloropropyltriethoxysilane was assessed by using three selected organophosphorus pesticides, namely, chlorpyrifos, profenofos, and malathion. Gas chromatography-mass spectrometry was used for detection of organophosphorus pesticides. Several vital parameters were optimized to identify the best extraction conditions. Under the optimum extraction conditions, solid-phase extraction-methyltrimethoxysilane-chloropropyltriethoxysilane method showed good linearity range (0.05-1 μg/mL) with coefficient of determination more than 0.995. The limits of detection obtained were in the range of 0.01-0.07 μg/mL and limits of quantification ranging from 0.03 to 0.21 μg/mL. The limits of detection obtained for the developed method were 2.3-6.5× lower than the limits of detection of commercial octadecyl silica sorbent. Real samples analysis was carried out by applying the developed method on red apple and purple grape samples. The developed method exhibited good recoveries (88.33-120.7%) with low relative standard deviations ranging from 1.6 to 3.3% compared to commercial octadecyl silica sorbent, which showed acceptable recoveries (70.3-100.2%) and relative standard deviations (6.3-8.8%). The solid-phase extraction-methyltrimethoxysilane-chloropropyltriethoxysilane method is presented as an alternative extraction method for determination of organophosphorus pesticides.
    Matched MeSH terms: Silanes/chemistry*
  11. Ahmad A, Razali MH, Mamat M, Mehamod FS, Anuar Mat Amin K
    Chemosphere, 2017 Feb;168:474-482.
    PMID: 27855344 DOI: 10.1016/j.chemosphere.2016.11.028
    This study aims to develop a highly efficient adsorbent material. CNTs are prepared using a chemical vapor deposition method with acetylene and synthesized mesoporous Ni-MCM41 as the carbon source and catalyst, respectively, and are then functionalized using 3-aminopropyltriethoxysilane (APTES) through the co-condensation method and loaded with commercial TiO2. Results of X-ray powder diffraction (XRD), Raman spectra, and Fourier transform infrared spectroscopy (FTIR) confirm that the synthesized CNTs grown are multi-walled carbon nanotubes (MWNTs). Transmission electron microscopy shows good dispersion of TiO2 nanoparticles onto functionalized-CNTs loaded TiO2, with the diameter of a hair-like structure measuring between 3 and 8 nm. The functionalized-CNTs loaded TiO2 are tested as an adsorbent for removal of methyl orange (MO) in aqueous solution, and results show that 94% of MO is removed after 10 min of reaction, and 100% after 30 min. The adsorption kinetic model of functionalized-CNTs loaded TiO2 follows a pseudo-second order with a maximum adsorption capacity of 42.85 mg/g. This study shows that functionalized-CNTs loaded TiO2 has considerable potential as an adsorbent material due to the short adsorption time required to achieve equilibrium.
    Matched MeSH terms: Silanes/chemistry*
  12. Rosly NZ, Ahmad SA, Abdullah J, Yusof NA
    Sensors (Basel), 2016 Aug 25;16(9).
    PMID: 27571080 DOI: 10.3390/s16091365
    In the present study, the construction of arrays on silicon for naked-eye detection of DNA dengue was demonstrated. The array was created by exposing a polyethylene glycol (PEG) silane monolayer to 254 nm ultraviolet (UV) light through a photomask. Formation of the PEG silane monolayer and photomodifed surface properties was thoroughly characterized by using atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and contact angle measurements. The results of XPS confirmed that irradiation of ultraviolet (UV) light generates an aldehyde functional group that offers conjugation sites of amino DNA probe for detection of a specific dengue virus target DNA. Employing a gold enhancement process after inducing the electrostatic interaction between positively charged gold nanoparticles and the negatively charged target DNA hybridized to the DNA capture probe allowed to visualize the array with naked eye. The developed arrays demonstrated excellent performance in diagnosis of dengue with a detection limit as low as 10 pM. The selectivity of DNA arrays was also examined using a single base mismatch and noncomplementary target DNA.
    Matched MeSH terms: Silanes/chemistry*
  13. Indarti E, Marwan, Rohaizu R, Wanrosli WD
    Int J Biol Macromol, 2019 Aug 15;135:106-112.
    PMID: 31128174 DOI: 10.1016/j.ijbiomac.2019.05.161
    Silylated cellulose has been successfully synthesized using TEMPO-oxidized nanocellulose (TEMPO-NC) from oil palm empty fruit bunch and 3-aminopropyltriethoxysilane (APS) in an ethanol/water medium at a low curing temperature of 40 °C as compared to those reported in the literature of above 100 °C. Confirmation of the grafting process can be seen from the new FTIR peaks at 810 cm-1 and 749 cm-1 which are attributed to the SiC stretching and SiC, and new 13C NMR signals at 10.3, 21.7 and 42.7 ppm which are assigned to C7, C8, and C9 of the silylated TEMPO-NC. The decrease in the intensities of the cellulose peaks of C2, C3, C6 and C6' in the 13C NMR indicates that silylation not only occurs on the hydroxyls, but more importantly on the TEMPO-NC carboxylic moiety of C6', which is postulated as being the primary factor for this successful modification. This is further corroborated by the emergence of three signals at 43, 61, and 69 ppm in the 29Si NMR spectrum which corresponds to Si(OSi)(OR)2R', Si(OSi)2(OR)R', and Si(OSi)3R' units respectively. Additional evidence is provided by the EDX which shows an increase in Si weight percent of 1.94 after reaction. This silylated cellulose from OPEFB has the potentials to be used as bionanocomposite reinforcing elements.
    Matched MeSH terms: Silanes/chemistry*
  14. Taniselass S, Arshad MKM, Gopinath SCB, Fathil MFM, Ibau C, Anbu P
    Mikrochim Acta, 2021 07 15;188(8):257.
    PMID: 34268634 DOI: 10.1007/s00604-021-04922-x
    A label-free chemical bonding strategy mediated by reduced graphene oxide (rGO) basal plane functional groups has been developed for cardiac Troponin I (cTnI) detection. Four different chemical strategies on respective electrode sensing surface were precedingly examined using electrochemical impedance spectroscopy. The impedimetric assessment was carried out by sweeping frequency at the range 0.1-500 kHz perturbated at a small amplitude of AC voltage (25 mV). The chemical strategy-4 denoted as S-4 shows a significant analytical performance on cTnI detection in spiked buffer and human serum, whereby the pre-mixture of rGO and (3-Aminopropyl)triethoxysilane (APTES) creates a large number of amine sites (-NH2), which significantly enhanced the antibody immobilization without excessive functionalization. The as-fabricated immunosensor exhibited an ultra-low limit of detection of 6.3 ag mL-1 and the lowest antigen concentration measured was at 10 ag mL-1. The immunosensor showed a linear and wide range of cTnI detection (10 ag mL-1-100 ng mL-1) in human serum with a regression coefficient of 0.9716, rapid detection (5 min of binding time), and stable and highly reproducible bioelectrode response with RSD 
    Matched MeSH terms: Silanes/chemistry
  15. Razak AA, Abu-Hassan MI, Al-Makramani BM, Al-Sanabani FA, Al-Shami IZ, Almansour HM
    J Contemp Dent Pract, 2016 Nov 01;17(11):920-925.
    PMID: 27965501
    AIM: The aim of this study was to evaluate the effect of surface treatments on shear bond strength (SBS) of Turkom-Cera (Turkom-Ceramic (M) Sdn. Bhd., Puchong, Malaysia) all-ceramic material cemented with resin cement Panavia-F (Kuraray Medical Inc., Okayama, Japan).

    MATERIALS AND METHODS: Forty Turkom-Cera ceramic disks (10 mm × 3 mm) were prepared and randomly divided into four groups. The disks were wet ground to 1000-grit and subjected to four surface treatments: (1) No treatment (Control), (2) sandblasting, (3) silane application, and (4) sandblasting + silane. The four groups of 10 specimens each were bonded with Panavia-F resin cement according to manufacturer's recommendations. The SBS was determined using the universal testing machine (Instron) at 0.5 mm/min crosshead speed. Failure modes were recorded and a qualitative micromorphologic examination of different surface treatments was performed. The data were analyzed using the one-way analysis of variance (ANOVA) and Tukey honestly significant difference (HSD) tests.

    RESULTS: The SBS of the control, sandblasting, silane, and sandblasting + silane groups were: 10.8 ± 1.5, 16.4 ± 3.4, 16.2 ± 2.5, and 19.1 ± 2.4 MPa respectively. According to the Tukey HSD test, only the mean SBS of the control group was significantly different from the other three groups. There was no significant difference between sandblasting, silane, and sandblasting + silane groups.

    CONCLUSION: In this study, the three surface treatments used improved the bond strength of resin cement to Turkom-Cera disks.

    CLINICAL SIGNIFICANCE: The surface treatments used in this study appeared to be suitable methods for the cementation of glass infiltrated all-ceramic restorations.

    Matched MeSH terms: Silanes/chemistry
  16. Mustafa AA, Matinlinna JP, Razak AA, Hussin AS
    J Investig Clin Dent, 2015 Aug;6(3):161-9.
    PMID: 24415731 DOI: 10.1111/jicd.12083
    AIM: To evaluate in vitro the effect of different concentrations of 2-hydroxyethyl methacrylate (HEMA) in experimental silane-based primers on shear bond strength of orthodontic adhesives.

    METHODS: Different volume percentages of HEMA were tested in four experimental silane-based primer solutions (additions of HEMA: 0, 5.0 vol%, 25.0 vol% and 50.0 vol%). An experimental silane blend (primer) of 1.0 vol% 3-isocyanatopropyltrimethoxysilane (ICMS) + 0.5% bis-1,2-(triethoxysilyl) ethane (BTSE) was prepared and used. The experimental primers together with the control group were applied onto acid-etched premolars for attachment of orthodontic brackets. After artificial aging by thermocycling the shear-bond strength was measured. The fractured surfaces of all specimens were examined under scanning electron microscopy (SEM) to evaluate the failure mode on the enamel surface.

    RESULTS: The experimental primers showed the highest shear-bond strength of 21.15 MPa (SD ± 2.70 MPa) and with 25 vol% showed a highly significant increase (P < 0.05) in bond strength. The SEM images showed full penetration of adhesive agents when using silane-based primers. In addition, the SEM images suggested that the predominant failure type was not necessarily the same as for the failure propagation.

    CONCLUSIONS: This preliminary study suggested that nonacidic silane-based primers with HEMA addition might be an alternative to for use as adhesion promoting primers.

    Matched MeSH terms: Silanes/chemistry*
  17. Miskam M, Abu Bakar NK, Mohamad S
    Talanta, 2014 Mar;120:450-5.
    PMID: 24468395 DOI: 10.1016/j.talanta.2013.12.037
    A solid phase extraction (SPE) method has been developed using a newly synthesized titanium (IV) butoxide-cyanopropyltriethoxysilane (Ti-CNPrTEOS) sorbent for polar selective extraction of aromatic amines in river water sample. The effect of different parameters on the extraction recovery was studied using the SPE method. The applicability of the sorbents for the extraction of polar aromatic amines by the SPE was extensively studied and evaluated as a function of pH, conditioning solvent, sample loading volume, elution solvent and elution solvent volume. The optimum experimental conditions were sample at pH 7, dichloromethane as conditioning solvent, 10 mL sample loading volume and 5 mL of acetonitrile as the eluting solvent. Under the optimum conditions, the limit of detection (LOD) and limit of quantification (LOQ) for solid phase extraction using Ti-CNPrTEOS SPE sorbent (0.01-0.2; 0.03-0.61 µg L(-1)) were lower compared with those achieved using Si-CN SPE sorbent (0.25-1.50; 1.96-3.59 µg L(-1)) and C18 SPE sorbent (0.37-0.98; 1.87-2.87 µg L(-1)) with higher selectivity towards the extraction of polar aromatic amines. The optimized procedure was successfully applied for the solid phase extraction method of selected aromatic amines in river water, waste water and tap water samples prior to the gas chromatography-flame ionization detector separation.
    Matched MeSH terms: Silanes/chemistry*
  18. Wan Ibrahim WA, Veloo KV, Sanagi MM
    J Chromatogr A, 2012 Mar 16;1229:55-62.
    PMID: 22326188 DOI: 10.1016/j.chroma.2012.01.022
    A novel sol-gel hybrid methyltrimethoxysilane-tetraethoxysilane (MTMOS-TEOS) was produced and applied as sorbent for solid phase extraction (SPE). Five selected organophosphorus pesticides (OPPs) were employed as model compounds to evaluate the extraction performance of the synthesized sol-gel organic-inorganic hybrid MTMOS-TEOS. Analysis was performed using gas chromatography-mass spectrometry. Several important SPE parameters were optimized. Under the optimum extraction conditions, the method using the sol-gel organic-inorganic hybrid MTMOS-TEOS as SPE sorbent showed good linearity in the range of 0.001-1 μg L(-1), good repeatability (RSD 2.1-3.1%, n=5), low limits of detection at S/N=3 (0.5-0.9 pg mL(-1)) and limit of quantification (1-3 pg mL(-1), S/N=10). The performance of the MTMOS-TEOS SPE was compared to commercial C18 Supelclean SPE since C18 SPE is widely used for OPPs. The MTMOS-TEOS SPE method LOD was 500-600 × lower than the LOD of commercial C18 SPE. The LOD achieved with the sol-gel organic-inorganic hybrid MTMOS-TEOS SPE sorbent allowed the detection of these OPPs in drinking water well below the level set by European Union (EU) at 0.1 μg L(-1) of each pesticides. The developed MTMOS-TEOS SPE method was successfully applied to real sample analysis of the selected OPPs from several water samples and its application extended to the analysis of several fruits samples. Excellent recoveries and RSDs of the OPPs were obtained from the various water samples (recoveries: 97-111%, RSDs 0.4-2.8%, n=3) and fruit samples (recoveries: 96-111%), RSDs 1-4%, n=5) using the sol-gel organic-inorganic hybrid MTMOS-TEOS SPE sorbent. Recoveries and RSDs of OPPs from river water samples and fruit samples using C18 Supelclean SPE sorbent were 91-97%, RSD 0.9-2.6, n=3 and 86-96%, RSD 3-8%, n=5, respectively). The novel sol-gel hybrid MTMOS-TEOS SPE sorbent demonstrate the potential as an alternative inexpensive extraction sorbent for OPPs with higher sensitivity for the OPPs.
    Matched MeSH terms: Silanes/chemistry*
  19. Jaafar J, Watanabe Y, Ikegami T, Miyamoto K, Tanaka N
    Anal Bioanal Chem, 2008 Aug;391(7):2551-6.
    PMID: 18458888 DOI: 10.1007/s00216-008-2063-3
    An anion exchange monolithic silica capillary column was prepared by surface modification of a hybrid monolithic silica capillary column prepared from a mixture of tetramethoxysilane (TMOS) and methyltrimethoxysilane (MTMS). The surface modification was carried out by on-column copolymerization of N-[3-(dimethylamino)propyl]acrylamide methyl chloride-quaternary salt (DMAPAA-Q) with 3-methacryloxypropyl moieties bonded as an anchor to the silica surface to form a strong anion exchange stationary phase. The columns were examined for their performance in liquid chromatography (LC) and capillary electrochromatography (CEC) separations of common anions. The ions were separated using 50 mM phosphate buffer at pH 6.6. Evaluation by LC produced an average of 30,000 theoretical plates (33 cm column length) for the inorganic anions and nucleotides. Evaluation by CEC, using the same buffer, produced enhanced chromatographic performance of up to ca. 90,000 theoretical plates and a theoretical plate height of ca. 4 mum. Although reduced efficiency was observed for inorganic anions that were retained a long time, the results of this study highlight the potential utility of the DMAPAA-Q stationary phase for anion separations.
    Matched MeSH terms: Silanes/chemistry
  20. Balakrishnan SR, Hashim U, Gopinath SC, Poopalan P, Ramayya HR, Veeradasan P, et al.
    Biosens Bioelectron, 2016 Oct 15;84:44-52.
    PMID: 26560969 DOI: 10.1016/j.bios.2015.10.075
    Rationally designed biosensing system supports multiplex analyses is warranted for medical diagnosis to determine the level of analyte interaction. The chemically functionalized novel multi-electrode polysilicon nanogap (PSNG) lab-on-chip is designed in this study, facilitates multiplex analyses for a single analyte. On the fabricated 69nm PSNG, biocompatibility and structural characteristics were verified for the efficient binding of Human Chorionic Gonadotropin (hCG). With the assistance of microfluidics, hCG sample was delivered via single-injection to 3-Aminopropyl(triethoxy)silane (APTES) and Glycidoxypropyl(trimethoxy)silane (GPMS) modified PSNG electrodes and the transduced signal was used to investigate the dielectric mechanisms for multiplex analyses. The results from amperometric response and impedance measurement delivered the scale of interaction between anti-hCG antibody and hCG that exhibited 6.5 times higher sensitivity for the chemical linker, APTES than GPMS. Under optimized experimental conditions, APTES and GPMS modified immunosensor has a limit of detection as 0.56mIU/ml and 2.93mIU/ml (at S/N=3), with dissociation constants (Kd) of 5.65±2.5mIU/ml and 7.28±2.6mIU/ml, respectively. These results suggest that multiplex analysis of single target could enhance the accuracy of detection and reliable for real-time comparative analyses. The designed PSNG is simple, feasible, requires low sample consumption and could be applied for any given multiplex analyses.
    Matched MeSH terms: Silanes/chemistry
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