Displaying publications 1 - 20 of 189 in total

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  1. Ibrahim Lakin I, Abbas Z, Azis RS, Ibrahim NA, Abd Rahman MA
    Materials (Basel), 2020 Oct 14;13(20).
    PMID: 33066690 DOI: 10.3390/ma13204581
    Oil palm empty fruit bunch (OPEFB) fiber/polylactic acid (PLA)-based composites filled with 6-22 wt.% multi-walled carbon nanotubes (MWCNTs) were prepared using a melt blend method. The composites were analyzed using X-ray diffraction (XRD), Fourier transforms infrared (FTIR), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) of the MWCNTs. The composites were characterized for complex permittivity using the coaxial probe at 8-12 GHz range and the transmission/reflection coefficients were measured through micro strip line. The dielectric permittivity measurements carried out at X-band frequency revealed that 22 wt.% MWCNTs nanocomposite display higher dielectric constant (ε') and dielectric loss (ε″) values of 4.23 and 0.65, respectively. A maximum absorption loss of 15.2 dB was obtained for the 22 wt.% nanocomposites at 11.75 GHz. This result suggests that PLA/OPEFB/MWCNTs composites are a promising cheap and lightweight material for the effective microwave absorption in the X-band frequency range.
    Matched MeSH terms: Fourier Analysis
  2. Abdul Rahman NH, Chieng BW, Ibrahim NA, Abdul Rahman N
    Polymers (Basel), 2017 Nov 07;9(11).
    PMID: 30965890 DOI: 10.3390/polym9110588
    The aim was to explore the utilization of tea leaf waste fibers (TLWF) as a source for the production of cellulose nanocrystals (CNC). TLWF was first treated with alkaline, followed by bleaching before being hydrolyzed with concentrated sulfuric acid. The materials attained after each step of chemical treatments were characterized and their chemical compositions were studied. The structure analysis was examined by Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD). From FTIR analysis, two peaks at 1716 and 1207 cm-1-which represent C=O stretching and C⁻O stretching, respectively-disappeared in the spectra after the alkaline and bleaching treatments indicated that hemicellulose and lignin were almost entirely discarded from the fiber. The surface morphology of TLWF before and after chemical treatments was investigated by scanning electron microscopy (SEM) while the dimension of CNC was determined by transmission electron microscopy (TEM). The extraction of CNC increased the surface roughness and the crystallinity index of fiber from 41.5% to 83.1%. Morphological characterization from TEM revealed the appearance of needle-like shaped CNCs with average diameter of 7.97 nm. The promising results from all the analyses justify TLWF as a principal source of natural materials which can produce CNC.
    Matched MeSH terms: Fourier Analysis
  3. Khanis NH, Ritikos R, Ahmad Kamal SA, Abdul Rahman S
    Materials (Basel), 2017 Jan 24;10(2).
    PMID: 28772460 DOI: 10.3390/ma10020102
    Nanostructured hydrogenated carbon nitride (CNx:H) thin films were synthesized on a crystal silicon substrate at low deposition temperature by radio-frequency plasma-enhanced chemical vapor deposition (PECVD). Methane and nitrogen were the precursor gases used in this deposition process. The effects of N₂ to the total gas flow rate ratio on the formation of CNx:H nanostructures were investigated. Field-emission scanning electron microscopy (FESEM), Auger electron spectroscopy (AES), Raman scattering, and Fourier transform of infrared spectroscopies (FTIR) were used to characterize the films. The atomic nitrogen to carbon ratio and sp² bonds in the film structure showed a strong influence on its growth rate, and its overall structure is strongly influenced by even small changes in the N₂:(N₂ + CH₄) ratio. The formation of fibrous CNx:H nanorod structures occurs at ratios of 0.7 and 0.75, which also shows improved surface hydrophobic characteristic. Analysis showed that significant presence of isonitrile bonds in a more ordered film structure were important criteria contributing to the formation of vertically-aligned nanorods. The hydrophobicity of the CNx:H surface improved with the enhancement in the vertical alignment and uniformity in the distribution of the fibrous nanorod structures.
    Matched MeSH terms: Fourier Analysis
  4. Saman SA, Chang KH, Abdullah AFL
    J Forensic Sci, 2021 Mar;66(2):608-618.
    PMID: 33202056 DOI: 10.1111/1556-4029.14625
    Abuse of solvent-based adhesives jeopardizes world population, especially the young generation. Adhesive-related exhibits encountered in forensic cases might need to be determined if they could have come from a particular source or to establish link between cases or persons. This study was aimed to discriminate solvent-based adhesives, especially to aid forensic investigation of glue sniffing activities. In this study, thirteen brands with three samples each, totaling at 39 adhesive samples, were analyzed using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy followed by chemometric methods. Experimental output showed that adhesive samples utilized in this study were less likely to change in their ATR-FTIR profiles over time, at least up to 2 months. No interference from plastic materials was noticed based on ATR-FTIR profile comparison. Physical examination could differentiate the samples into two groups, namely contact adhesives and cement adhesives. A principal component analysis-score linear discriminative analysis (PC-score LDA) model resulted in 100% and 98.6% correct classification in discriminating the two groups of adhesive samples, forming seven discriminative clusters. Test set with adhesive samples applied glass slide and plastic substrates also demonstrated a 100% correct classification into their respective groups. As a conclusion, the method allowed for discrimination of adhesive samples based on the spectral features, displaying relationship among samples. It is hoped that this comparative information is beneficial to trace the possible source of solvent-based adhesives, whenever they are recovered from a crime scene, for forensic investigation.
    Matched MeSH terms: Fourier Analysis
  5. Teoh WK, Md Muslim NZ, Ismail ML, Chang KH, Abdullah AFL
    Anal Methods, 2021 04 07;13(13):1601-1611.
    PMID: 33730137 DOI: 10.1039/d1ay00075f
    Due to the outbreak of the COVID-19 pandemic, practicing personal hygiene such as frequent hand sanitising has become a norm. The making of effective hand sanitiser products should follow the recommended formulations, but the high demand worldwide for such affordable products could have made them a candidate for counterfeiting, thus deserving forensic determination and profiling for source determination or supply chain tracing. In this study, determination and discrimination of hand sanitisers was carried out by employing attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy combined with chemometrics. Fifty commercially available hand sanitisers were obtained from the market and analysed. ATR-FTIR profiles of each sanitiser were compared and decomposed by principal component analysis (PCA) followed by linear discriminant analysis (LDA). Physical observation enabled the discrimination of seven samples based on their respective colours, the presence of beads and their colours, and the physical forms of formulations. Subsequently, eight distinct patterns were observed through visual comparison of ATR-FTIR profiles of the remaining 43 samples. An initial unsupervised exploratory PCA model indicated the separation of two main groups with ATR-FTIR profiles similar to those of ethanol and isopropanol, respectively. The PCA score-LDA model provided good predictions, with a 100% correct classification into eight different groups. In conclusion, this study demonstrated a quick determination and discrimination of hand sanitiser samples, allowing screening for any restricted components and sample-to-sample comparison.
    Matched MeSH terms: Fourier Analysis
  6. Moradihamedani P, Abdullah AH
    Water Sci Technol, 2017 May;75(10):2422-2433.
    PMID: 28541950 DOI: 10.2166/wst.2017.122
    Neat cellulose acetate (CA) and CA/polysulfone (PSf) blend ultrafiltration membranes in the presence of polyvinylpyrrolidone as a pore former were prepared via a phase inversion technique. The prepared membranes were characterized by Fourier transform infrared, scanning electron microscopy, mechanical strength, water content, porosity, permeate flux and heavy metals (Pb2+, Cd2+, Zn2+ and Ni2+) rejection to comprehend the impact of polymer blend composition and additive on the properties of the modified membranes. The water flux expanded by increasing of PSf content in the polymer composition. CA/PSf (60/40) had the highest flux among prepared membranes. Prepared blend membranes were able to remove heavy metals from water in the following order: Pb2+ > Cd2+ > Zn2+ > Ni2+. The CA/PSf (80/20) blend membrane had great performance among prepared membranes due to the high heavy metals removal and permeate flux.
    Matched MeSH terms: Fourier Analysis
  7. Suradi SH, Abdullah KA
    Curr Med Imaging, 2021 Jan 26.
    PMID: 33504312 DOI: 10.2174/1573405617666210127101101
    BACKGROUND: Digital mammograms with appropriate image enhancement techniques will improve breast cancer detection, and thus increase the survival rates. The objectives of this study were to systematically review and compare various image enhancement techniques in digital mammograms for breast cancer detection.

    METHODS: A literature search was conducted with the use of three online databases namely, Web of Science, Scopus, and ScienceDirect. Developed keywords strategy was used to include only the relevant articles. A Population Intervention Comparison Outcomes (PICO) strategy was used to develop the inclusion and exclusion criteria. Image quality was analyzed quantitatively based on peak signal-noise-ratio (PSNR), Mean Squared Error (MSE), Absolute Mean Brightness Error (AMBE), Entropy, and Contrast Improvement Index (CII) values.

    RESULTS: Nine studies with four types of image enhancement techniques were included in this study. Two studies used histogram-based, three studies used frequency-based, one study used fuzzy-based and three studies used filter-based. All studies reported PSNR values whilst only four studies reported MSE, AMBE, Entropy and CII values. Filter-based was the highest PSNR values of 78.93, among other types. For MSE, AMBE, Entropy, and CII values, the highest were frequency-based (7.79), fuzzy-based (93.76), filter-based (7.92), and frequency-based (6.54) respectively.

    CONCLUSION: In summary, image quality for each image enhancement technique is varied, especially for breast cancer detection. In this study, the frequency-based of Fast Discrete Curvelet Transform (FDCT) via the UnequiSpaced Fast Fourier Transform (USFFT) shows the most superior among other image enhancement techniques.

    Matched MeSH terms: Fourier Analysis
  8. Rasheed M, Jawaid M, Karim Z, Abdullah LC
    Molecules, 2020 Jun 18;25(12).
    PMID: 32570929 DOI: 10.3390/molecules25122824
    Bamboo fibers are utilized for the production of various structures, building materials, etc. and is of great significance all over the world especially in southeast Asia. In this study, the extraction of microcrystalline cellulose (MCC) was performed using bamboo fibers through acid hydrolysis and subsequently different characterizations were carried out using various advanced techniques. Fourier transform infrared (FTIR) spectroscopy analysis has indicated the removal of lignin from MCC extracted from bamboo pulp. Scanning Electron Microscopy (SEM) revealed rough surface and minor agglomeration of the MCC. Pure MCC, albeit with small quantities of impurities and residues, was obtained, as revealed by Energy Dispersive X-ray (EDX) analysis. X-ray diffraction (XRD) indicates the increase in crystallinity from 62.5% to 82.6%. Furthermore, the isolated MCC has slightly higher crystallinity compared to commercial available MCC (74%). The results of thermal gravimetric analysis (TGA) demonstrate better thermal stability of isolated MCC compared to its starting material (Bamboo fibers). Thus, the isolated MCC might be used as a reinforcing element for the production of green composites and it can also be utilized as a starting material for the production of crystalline nanocellulose in future.
    Matched MeSH terms: Fourier Analysis
  9. Iqhrammullah M, Marlina M, Khalil HPSA, Kurniawan KH, Suyanto H, Hedwig R, et al.
    Polymers (Basel), 2020 Jun 09;12(6).
    PMID: 32526903 DOI: 10.3390/polym12061317
    Global pollution from toxic metal waste has resulted in increased research on toxic metal adsorption. A cellulose acetate-polyurethane (CA-PU) film adsorbent was successfully prepared in this research. The cellulose acetate-polyurethane film adsorbent was prepared with a polycondensation reaction between cellulose acetate and methylene diphenyl diisocyanate. The CA-PU bond formation was confirmed by functional group analysis obtained from Fourier transform infrared (FTIR) spectroscopy. The obtained film was characterized for improved tensile and thermal properties with the addition of methylene diphenyl diisocyanate (MDI). The adsorption ability of the obtained film was evaluated with laser-induced breakdown spectroscopy (LIBS). The best film adsorbent from the LIBS was selected and studied for adsorption isotherm. The FTIR analysis confirmed the formation of the CA-PU bond from the polycondensation between cellulose acetate and the methylene diphenyl diisocyanate. The result showed that the addition of methylene diphenyl diisocyanate (MDI) resulted in the urethane network's growth. The characterization result showed an improvement in the morphology, thermal stability, and tensile strength of the film. The LIBS studies showed improvement in the adsorption of Pb2+ with CA-PU compared with the neat CA. The isotherm studies revealed that Pb2+ adsorption by cellulose acetate-polyurethane film adsorbent was heterogeneously dependent on the Freundlich isotherm model (R2 = 0.97044). Overall, the polycondensation method proposed by this study enhanced the Pb2+ removal, and was comparable to those reported in previous studies.
    Matched MeSH terms: Fourier Analysis
  10. Habiba U, Joo TC, Siddique TA, Salleh A, Ang BC, Afifi AM
    Int J Biol Macromol, 2017 Nov;104(Pt A):1133-1142.
    PMID: 28690164 DOI: 10.1016/j.ijbiomac.2017.07.007
    The chitosan/polyvinyl alcohol/TiO2 composite was synthesized. Two different degrees of deacetylation of chitosan were prepared by hydrolysis to compare the effectiveness of them. The composite was analyzed via field emission scanning electron microscopy, Fourier transform infrared, X-ray diffraction, thermal gravimetric analysis, weight loss test and adsorption study. The FTIR and XRD results proved the interaction among chitosan, PVA and TiO2 without any chemical reaction. It was found that, chitosan with higher degree of deacetylation has better stability. Furthermore, it also showed that higher DD of chitosan required less time to reach equilibrium for methyl orange. The adsorption followed the pseudo-second-order kinetic model. The Langmuir and Freundlich isotherm models were fitted well for isotherm study. Adsorption capacity was higher for the composite containing chitosan with higher DD. The dye removal rate was independent of the dye's initial concentration. The adsorption capacity was increased with temperature and it was found from reusability test that the composite containing chitosan with higher DD is more reusable. It was notable that adsorption capacity was even after 15 runs. Therefore, chitosan/PVA/TiO2 composite can be a very useful material for dye removal.
    Matched MeSH terms: Fourier Analysis
  11. Habiba U, Siddique TA, Joo TC, Salleh A, Ang BC, Afifi AM
    Carbohydr Polym, 2017 Feb 10;157:1568-1576.
    PMID: 27987870 DOI: 10.1016/j.carbpol.2016.11.037
    A chitosan/polyvinyl alcohol (PVA)/zeolite composite was fabricated in this study. The composite was analyzed through field emission scanning electron microscopy, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), thermogravimetric analysis, and weight loss test. FTIR and XRD results revealed a strong interaction among chitosan, PVA, and zeolite. Weight loss test results indicated that the composite was stable in acidic and basic media. Congo red was removed through flocculation, and the removal rate was 94% at an initial concentration of 100mg/L for a dose of 1g/L. The removal rate of methyl orange was controlled by adsorption at an initial concentration of less than 100mg/L. Flocculation occurred at high concentrations. The removal rate was also 94% at an initial concentration of 500mg/L for a dose of 5g/L. The adsorption behavior of the composite for the removal of methyl orange and Cr(VI) was described by using a pseudo-second-order kinetic model. The adsorption capacity of the composite for Cr(VI) was 450mg/g. Therefore, the synthesized composite exhibited versatility during the removal of dyes and heavy metals.
    Matched MeSH terms: Fourier Analysis
  12. Hassan N, Ahmad T, Ashaari A, Awang SR, Mamat SS, Wan Mohamad WM, et al.
    Results Phys, 2021 Jun;25:104267.
    PMID: 33968605 DOI: 10.1016/j.rinp.2021.104267
    Complex systems require rigorous analysis using effective method, in order to handle and interpret their information. Spectrum produced from Fourier transform infrared (FTIR) instrument is an example of a complex system, due to their overlapped bands and interactions within the spectrum. Thus, chemometrics techniques are required to further analyze the data, in particular, chemometrics fuzzy autocatalytic set (c-FACS). The c-FACS is initially used to analyze the FTIR spectra of gelatins. However, in this study, the c-FACS is generalized and implemented for analysis of Coronavirus disease 2019 (Covid-19), particularly, the pandemic outbreak in Malaysia. The daily Covid-19 cases in states in Malaysia are modeled and analyzed using c-FACS, to observe the trend and severity of the disease in Malaysia. As a result, the classification of severity of zones in Malaysia are identified. The obtained results offer descriptive insight for strategizing purposes in combating the Covid-19 outbreak in Malaysia.
    Matched MeSH terms: Fourier Analysis
  13. Sagadevan S, Venilla S, Marlinda AR, Johan MR, Wahab YA, Zakaria R, et al.
    J Nanosci Nanotechnol, 2020 Apr 01;20(4):2488-2494.
    PMID: 31492266 DOI: 10.1166/jnn.2020.17185
    Herein, we report the effect of synthesis temperature on the morphologies, optical and electronic properties of magnesium oxide (MgO) nanostructures. The MgO nanostructures were synthesized at different temperatures, i.e., 100 °C, 300 °C, and 600 °C by simple chemical reaction process and their morphology, particle size, optical, and electrical properties were examined by different techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and UV-Vis. spectroscopy. The morphological investigations revealed that various morphologies of MgO nanostructures, i.e., nanoparticles, nanosheet networks, and nanoneedles were synthesized at 100 °C, 300 °C, and 600 °C. The XRD results confirmed that with increasing the synthesis temperature, the crystallinity of the synthesized nanostructures increases. Further, the dielectric properties and AC conductivity at various frequencies for MgO nanostructures were studied which revealed that the dielectric losses decrease with increase in frequency and temperature. In addition, the observed band gap decreases from 4.89 eV to 4.438 eV (100 °C to 600 °C) representing its increase in the conductivity.
    Matched MeSH terms: Fourier Analysis
  14. Kazemi M, Bala Krishnan M, Aik Howe T
    Iran J Allergy Asthma Immunol, 2013 Sep;12(3):236-46.
    PMID: 23893807
    In this paper, the method of differentiating asthmatic and non-asthmatic patients using the frequency analysis of capnogram signals is presented. Previously, manual study on capnogram signal has been conducted by several researchers. All past researches showed significant correlation between capnogram signals and asthmatic patients. However all of them are just manual study conducted through the conventional time domain method. In this study, the power spectral density (PSD) of capnogram signals is estimated by using Fast Fourier Transform (FFT) and Autoregressive (AR) modelling. The results show the non-asthmatic capnograms have one component in their PSD estimation, in contrast to asthmatic capnograms that have two components. Furthermore, there is a significant difference between the magnitude of the first component for both asthmatic and non-asthmatic capnograms. The effectiveness and performance of manipulating the characteristics of the first frequency component, mainly its magnitude and bandwidth, to differentiate between asthmatic and non-asthmatic conditions by means of receiver operating characteristic (ROC) curve analysis and radial basis function (RBF) neural network were shown. The output of this network is an integer prognostic index from 1 to 10 (depends on the severity of asthma) with an average good detection rate of 95.65% and an error rate of 4.34%. This developed algorithm is aspired to provide a fast and low-cost diagnostic system to help healthcare professional involved in respiratory care as it would be possible to monitor severity of asthma automatically and instantaneously.
    Matched MeSH terms: Fourier Analysis*
  15. Al Balawi AN, Yusof NA, Kamaruzaman S, Mohammad F, Wasoh H, Al-Lohedan HA
    Materials (Basel), 2019 Apr 11;12(7).
    PMID: 30978916 DOI: 10.3390/ma12071178
    The present study deals with the synthesis, characterization, and DNA extraction of poly(4,4'-cyclohexylidene bisphenol oxalate)/silica (Si) nanocomposites (NCs). The effects of varying the monomer/Si (3.7%, 7%, and 13%) ratio towards the size and morphology of the resulting NC and its DNA extraction capabilities have also been studied. For the NC synthesis, two different methods were followed, including the direct mixing of poly(4,4'-cyclohexylidene bisphenol oxalate) with fumed Si, and in situ polymerization of the 4,4'-cyclohexylidene bisphenol monomer in the presence of fumed silica (11 nm). The formed NCs were thoroughly investigated by using different techniques such as scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), powdered X-ray diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis where the results supported that there was the successful formation of poly(4,4'-cyclohexylidene bisphenol oxalate)/Si NC. Within the three different NC samples, the one with 13% Si was found to maintain a very high surface area of 12.237 m²/g, as compared to the other two samples consisting of 7% Si (3.362 m²/g) and 3.7% Si (1.788 m²/g). Further, the solid phase DNA extraction studies indicated that the efficiency is strongly influenced by the amount of polymer (0.2 g > 0.1 g > 0.02 g) and the type of binding buffer. Among the three binding buffers tested, the guanidine hydrochloride/EtOH buffer produced the most satisfactory results in terms of yield (1,348,000 ng) and extraction efficiency (3370 ng/mL) as compared to the other two buffers of NaCl (2 M) and phosphate buffered silane. Based on our results, it can be indicated that the developed poly(4,4'-cyclohexylidene bisphenol oxalate)/Si NC can serve as one of the suitable candidates for the extraction of DNA in high amounts as compared to other traditional solid phase approaches.
    Matched MeSH terms: Fourier Analysis
  16. Rasheed M, Jawaid M, Parveez B, Hussain Bhat A, Alamery S
    Polymers (Basel), 2021 Feb 01;13(3).
    PMID: 33535490 DOI: 10.3390/polym13030465
    The present study aims to develop a biodegradable polymer blend that is environmentally friendly and has comparable tensile and thermal properties with synthetic plastics. In this work, microcrystalline cellulose (MCC) extracted from bamboo-chips-reinforced poly (lactic acid) (PLA) and poly (butylene succinate) (PBS) blend composites were fabricated by melt-mixing at 180 °C and then hot pressing at 180 °C. PBS and MCC (0.5, 1, 1.5 wt%) were added to improve the brittle nature of PLA. Field emission scanning electron microscopy (FESEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscope (FTIR), thermogravimetric analysis (TGA), differential thermogravimetry (DTG), differential scanning calorimetry (DSC)), and universal testing machine were used to analyze morphology, crystallinity, physiochemical, thermal, and tensile properties, respectively. The thermal stability of the PLA-PBS blends enhanced on addition of MCC up to 1wt % due to their uniform dispersion in the polymer matrix. Tensile properties declined on addition of PBS and increased with MCC above (0.5 wt%) however except elongation at break increased on addition of PBS then decreased insignificantly on addition of MCC. Thus, PBS and MCC addition in PLA matrix decreases the brittleness, making it a potential contender that could be considered to replace plastics that are used for food packaging.
    Matched MeSH terms: Fourier Analysis
  17. Sagadevan S, Vennila S, Suraiya Begum SN, Wahab YA, Hamizi NAB, Marlinda AR, et al.
    J Nanosci Nanotechnol, 2020 09 01;20(9):5452-5457.
    PMID: 32331117 DOI: 10.1166/jnn.2020.17855
    Nanostructure materials are of interest in last few decades due to their unique size-dependent physio-chemical properties. In this paper, zinc oxide (ZnO) and barium doped ZnO nanodisks (NDs) were synthesized using sonochemical method and characterized by various techniques such as X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, scanning electron microscope (SEM), UV-vis absorption and dielectric measurements. The XRD and FTIR studies confirm the crystalline nature of ZnO NDs, and the average crystallite size was found to be ~25 nm for pure ZnO and ~22 nm for Ba doped ZnO NDs. SEM study confirmed the spherical shaped ZnO NDs with average sizes in the range of 20-30 nm. The maximum absorbance was obtained in the 200-500 nm regions with a prominent peak absorbance were observed by UV-vis spectra. The corresponding band gap for ZnO NDs and Ba doped ZnO NDs were calculated using Tauc's plot and was found to be 3.12 and 3.04, respectively. The conductivity and dielectric measurements as a function of frequency have been studied.
    Matched MeSH terms: Fourier Analysis
  18. Francis Davin Nyoro, Siong Fong Sim, Amelia Laccy Jeffrey Kimura
    MyJurnal
    This study reports the caffeine content in seven locally available coffee. The caffeine was extracted with chloroform and analysed using Fourier Transform Infrared (FTIR). The method reports an average recovery of 101% with the limit of determination established at 0.1%. The absorption band at 1654 cm-1 was used to construct the calibration curve for quantification of caffeine where the regression was fitted with satisfactory linearity. An average of 0.55% of caffeine was detected in the seven coffee products with Arabica coffee demonstrating lower caffeine concentration. The study evidenced that caffeine content in coffee is determined by the coffee types. The caffeine content found in the local coffee products was relatively lower likely due to the solvent types, extraction procedure and analytical method used.
    Matched MeSH terms: Fourier Analysis
  19. Nurrulhidayah, A.F., Che Man, Y.B., Shuhaimi, M., Rohman, A., Khatib, A., Amin, I.
    MyJurnal
    The use of Fourier transform infrared (FTIR) spectroscopy coupled with chemometric techniques to differentiate butter from beef fat (BF) was investigated. The spectral bands associated with butter, BF, and their mixtures were scanned, interpreted, and identified by relating them to those spectroscopically representative to pure butter and BF. For quantitative analysis, partial least square (PLS) regression was used to develop a calibration model at the selected fingerprint regions of 1500-1000 cm-1, with the values of coefficient of determination (R2) and root mean square error of calibration (RMSEC) are 0.999 and 0.89% (v/v), respectively. The PLS calibration model was subsequently used for the prediction of independent samples containing butter in the binary mixtures with BF. Using 6 principal components, root mean square error of prediction (RMSEP) is 2.42% (v/v). These results proved that FTIR spectroscopy in combination with multivariate calibration can be used for the detection and quantification of BF in butter formulation for authentication use.
    Matched MeSH terms: Fourier Analysis
  20. Praveena SM, Aris AZ
    Environ Geochem Health, 2018 Apr;40(2):749-762.
    PMID: 28929262 DOI: 10.1007/s10653-017-0021-8
    This study aims to determine the status of potentially toxic element concentrations of road dust in a medium-sized city (Rawang, Malaysia). This study adopts source identification via enrichment factor, Pearson correlation analysis, and Fourier spectral analysis to identify sources of potentially toxic element concentrations in road dust in Rawang City, Malaysia. Health risk assessment was conducted to determine potential health risks (carcinogenic and non-carcinogenic risks) among adults and children via multiple pathways (i.e., ingestion, dermal contact, and inhalation). Mean of potentially toxic element concentrations were found in the order of Pb > Zn > Cr(IV) > Cu > Ni > Cd > As > Co. Source identification revealed that Cu, Cd, Pb, Zn, Ni, and Cr(IV) are associated with anthropogenic sources in industrial and highly populated areas in northern and southern Rawang, cement factories in southern Rawang, as well as the rapid development and population growth in northwestern Rawang, which have resulted in high traffic congestion. Cobalt, Fe, and As are related to geological background and lithologies in Rawang. Pathway orders for both carcinogenic and non-carcinogenic risks are ingestion, dermal contact, and inhalation, involving adults and children. Non-carcinogenic health risks in adults were attributed to Cr(IV), Pb, and Cd, whereas Cu, Cd, Cr(IV), Pb, and Zn were found to have non-carcinogenic health risks for children. Cd, Cr(IV), Pb, and As may induce carcinogenic risks in adults and children, and the total lifetime cancer risk values exceeded incremental lifetime.
    Matched MeSH terms: Fourier Analysis
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