Poly(β-cyclodextrin-ionic liquid) grafted magnetic nanoparticles combined with 1-octanol as supramolecular solvents (SUPRASs) presenting new ferrofluid was developed and successfully applied in the dispersive liquid-phase microextraction of seven representative polycyclic aromatic hydrocarbons. One variable at-a-time (OVAT) analysis and response surface methodology (RSM) were used for efficient optimization of the main variables. The calibration curves were found to be linear in the range of 0.1-150 ng mL-1 with correlation of determinations (R2) ranging from 0.9944 to 0.9986. Detection limits ranged at 0.02-0.07 ng mL-1 for all studied PAHs. The intra and inter-day precision values (RSD %) were in the range of 1.80%-7.56% and 2.97%-8.23%, respectively. The ferrofluid showed a satisfactory reproducibility between 1.72% and 5.90%, and acceptable recovery values at 84%-110% were obtained for the real samples analysis. The optimized method was successfully applied to access the content safety of the PAHs studied in a variety of commercial food and beverages available in Malaysia.
The oil of Adenanthera pavonina L. seeds was analysed by chromatographic and instrumental means. The oil was found to be rich in neutral lipids (86.2%), and low in polar lipids (13.8%). The neutral lipids consisted mainly of triacylglycerols (64.2%). Unsaturated fatty acids were found as high as 71%, while the percentage of saturated fatty acids was only 29%. GC and GC/MS analyses revealed linoleic, oleic and lignocerotic acid to be predominant among all fatty acids in the A. pavonina oil, whereas stigmasterol was the major steroid identified within this study. Subsequently, the oil was used for preparation of submicron oil-in-water (o/w) lipid emulsions. Lipid emulsions were formulated by using soybean lecithin (SL) to investigate their particle size, Zeta potential and stability at the different oil and SL ratios. The results obtained indicate possible applications of the tested oil in pharmaceutical and medical fields as drug and cosmetic active ingredient carriers.
The Inverse Gas Chromatography (IGC) technique has been employed for the surface thermo-dynamic characterization of the polymer Poly(vinylidene chloride-co-acrylonitrile) (P(VDC-co-AN)) in its pure form. IGC attributes, such as London dispersive surface energy, Gibbs free energy, and Guttman Lewis acid-base parameters were analyzed for the polymer (P(VDC-co-AN)). The London dispersive surface free energy ( γ S L ) was calculated using the Schultz and Dorris-Gray method. The maximum surface energy value of (P(VDC-co-AN )) is found to be 29.93 mJ·m - 2 and 24.15 mJ·m - 2 in both methods respectively. In our analysis, it is observed that the γ S L values decline linearly with an increase in temperature. The Guttman-Lewis acid-base parameter K a , K b values were estimated to be 0.13 and 0.49. Additionally, the surface character S value and the correlation coefficient were estimated to be 3.77 and 0.98 respectively. After the thermo-dynamic surface characterization, the (P(VDC-co-AN)) polymer overall surface character is found to be basic. The substantial results revealed that the (P(VDC-co-AN)) polymer surface contains more basic sites than acidic sites and, hence, can closely associate in acidic media. Additionally, visual traits of the polymer (P(VDC-co-AN)) were investigated by employing Computer Vision and Image Processing (CVIP) techniques on Scanning Electron Microscopy (SEM) images captured at resolutions ×50, ×200 and ×500. Several visual traits, such as intricate patterns, surface morphology, texture/roughness, particle area distribution ( D A ), directionality ( D P ), mean average particle area ( μ a v g ) and mean average particle standard deviation ( σ a v g ), were investigated on the polymer's purest form. This collective study facilitates the researches to explore the pure form of the polymer Poly(vinylidene chloride-co-acrylonitrile) (P(VDC-co-AN )) in both chemical and visual perspective.
The growth in driving force and popularity of cyclodextrin (CDs) and ionic liquids (ILs) as promising materials in the field of analytical chemistry has resulted in an exponentially increase of their exploitation and production in analytical chemistry field. CDs belong to the family of cyclic oligosaccharides composing of α-(1,4) linked glucopyranose subunits and possess a cage-like supramolecular structure. This structure enables chemical reactions to proceed between interacting ions, radical or molecules in the absence of covalent bonds. Conversely, ILs are an ionic fluids comprising of only cation and anion often with immeasurable vapor pressure making them as green or designer solvent. The cooperative effect between CD and IL due to their fascinating properties, have nowadays contributed their footprints for a better development in analytical chemistry nowadays. This comprehensive review serves to give an overview on some of the recent studies and provides an analytical trend for the application of CDs with the combination of ILs that possess beneficial and remarkable effects in analytical chemistry including their use in various sample preparation techniques such as solid phase extraction, magnetic solid phase extraction, cloud point extraction, microextraction, and separation techniques which includes gas chromatography, high-performance liquid chromatography, capillary electrophoresis as well as applications of electrochemical sensors as electrode modifiers with references to recent applications. This review will highlight the nature of interactions and synergic effects between CDs, ILs, and analytes. It is hoped that this review will stimulate further research in analytical chemistry.
In this study, a new magnetic adsorbent based on magnetite-sporopollenin/graphene oxide (Fe3O4-SP/GO) was successfully developed. The adsorbent was applied for magnetic solid phase extraction (MSPE) of three selected polar organophosphorus pesticides (OPPs), namely, dimethoate, phenthoate, and phosphamidon, prior to gas chromatography analysis with electron capture detection (GC-μECD). The Fe3O4-SP/GO adsorbent combines the advantages of superior adsorption capability of the modified sporopollenin (SP) with graphene oxide (GO) and magnetite (Fe3O4) for easy isolation from sample solution. Several MSPE parameters were optimized. Under optimized conditions, excellent linearity (R2 ≥ 0.9994) was achieved using matrix match calibration in the range of 0.1 to 500 ng mL-1. The limit of detection (LOD) method (S/N = 3) was from 0.02 to 0.05 ng mL-1. The developed Fe3O4-SP/GO MSPE method was successfully applied for the determination of these three polar OPPs in cucumber, long beans, bell pepper, and tomato samples. Good recoveries (81.0-120.0%) and good relative standard deviation (RSD) (1.4-7.8%, n = 3) were obtained for the spiked OPPs (1 ng mL-1) from real samples. This study is beneficial for adsorptive removal of toxic pesticide compounds from vegetable samples.
Omega-3 fatty acids have been shown to reduce the risk of chronic diseases like cardiovascular disease and cancer as well as promote brain development among infants and children. This study was carried out to compare total protein, fat and omega-3 fatty acids content of raw and pressurized fish of P. pangasius (yellowtail catfish) and H. macrura (long tail shad). The fish was cooked using pressure cooker for six minute to be pressurized. The protein content was determined by using Kjedahl method while total fat was determined using solvent extraction using chloroform and methanol. Fatty acid methyl esters (FAME) were prepared by a direct transesterification method, and quantified by gas chromatography using external standard. Results showed that marine fish H. macrura (long tail shad) had higher content (p < 0.05) of protein (18.30 ± 0.040 g/100 g), fat (10.965 ± 1.610 g/100 g), EPA (11.83 ± 0.02 g/100 g) and DHA (5.96 ± 0.31 g/100 g) compared to freshwater fish P. pangasius (yellowtail catfish). The protein content of pressurized fish was higher compare to raw fish, but there was no difference in total fat and omega-3 fatty acids content between raw and pressurized of freshwater fish P. pangasius and marine fish, H. macrura. In conclusion, marine fish are better source of protein, fat and omega-3 content, while pressurized fish shown to have comparable amount of protein, fat and omega-3 fatty acids content with raw fish. The result obtained assist the consumers to prepare a healthy menu in order to retain the protein and omega-3 fatty acids content of fish through healthy way of cooking.
Water contamination by herbicides and chelating agents is increasing mainly due to the
increasing agricultural activities. Water contamination by these compounds has become a
concern due to their adverse effects to the environment and humans. Seven sampling sites of
water sources in Selangor and Johor were chosen for the study. Contamination level of
Mecoprop (MCCP), Nitrilotriacetic acid (NTA) and Ethylenediaminetetraacetic acid (EDTA) in
these water body areas was determined by using Gas Chromatography-Electron Capture
Detector (GC-ECD). Our results indicated that water samples of Sungai Melot in Selangor
showed the highest presence of EDTA. MCCP was detected at a high level at Sungai Sarang
Buaya, Johor while NTA showed similar level of concentration at three different sites, Ladang
10, Ladang Sayur and Mardi, Selangor.
Four species of bacteria, Acinetobacter lwoffii, Aeromonas hydrophila, Pseudomonas aeruginosa and Pseudomonas putida, were isolated from soil contaminated with hydrocarbons and selected for the determination of growth requirements and the ability to degrade petroleum hydrocarbon. The bacteria were grown in mineral salt medium (MSM) supplemented with two types of crude oil, either Sumandak or South Angsi at 1% (v/v) concentration. The optimum pH for growth of A. hydrophila and P. aeruginosa was 6.5 when grown with Sumandak and South Angsi oil. For A. lwoffii and P. putida the optimum pH for growth with Sumandak and South Angsi oil was 6.5 or 7.0, respectively. The growth of P. aeruginosa was the highest in MSM when supplemented with 1% South Angsi oil and 0.5% tryptone at pH 6.5 while, in Sumandak oil the growth was the highest when yeast extract was added. Gas chromatography analysis showed that the South Angsi crude oil components of C12 to C25 were more extensively degraded by A. lwoffii after 24 h of incubation compared to the other bacteria over the same period.
The data presented in this article were generated through the gas chromatography (GC) with a flame ionization detector (FID). The flaxseed oil was converted into fatty acid methyl ester (FAME) then used in the GC with FID and observe the retention time of different fatty acid present in the flaxseed oil. The observed retention time was compared with the standard fatty acid to confirm the specific fatty acid presence in the flaxseed oil. The part of the data is used in the article "Optimization of the process variable for biodiesel production by transesterification of flaxseed oil and produced biodiesel characterizations" Renewable Energy journal (Ahmad et al., 2019).
A comparison of dissipation of chlorothalonil, chlorpyrifos, and profenofos in a Malaysian agricultural soil between the field experiment and simulation by the PERSIST model was studied. A plot of sweet pea (Pisum sativum) from a farm in the Cameron Highlands was selected for the field experiment. The plot was treated with chlorothalonil, chlorpyrifos, and profenofos. Core soil collection was conducted according to the sampling schedule. Residues of the three pesticides were analyzed in the laboratory. Simulations of the three pesticides' persistency were also conducted using a computer-run software PERSIST. Generally, predicted data obtained using PERSIST were found to be high for the three pesticides except for one field measurement of chlorpyrifos. The predicted data for profenofos, which is the most mobile of the three pesticides tested, was not well matched with the observed data compared to chlorothalonil and chlorpyrifos.
This work focuses on the remediation of polycyclic aromatic hydrocarbon (PAH)-contaminated soil using modified Fenton (MF) treatment coupled with a novel chelating agent (CA), a more effective technique among currently available technologies. The performance of MF treatment to promote PAH oxidation in artificially contaminated soil was investigated in a packed column with a hydrogen peroxide (H(2)O(2)) delivery system simulating in-situ soil flushing which is more representative of field conditions. The effectiveness of process parameters H(2)O(2)/soil, Fe(3+)/soil, CA/soil weight ratios and reaction time were studied using a 2(4) three level factorial design experiments. An optimised operating condition of the MF treatment was observed at H(2)O(2)/soil 0.05, Fe(3+)/soil 0.025, CA/soil 0.04 and 3h reaction time with 79.42% and 68.08% PAH removals attainable for the upper and lower parts of the soil column respectively. The effects of natural attenuation and biostimulation process as post-treatment in the remediation of the PAH-contaminated soil were also studied. In all cases, 3-aromatic ring PAH (phenanthrene) was more readily degraded than 4-aromatic ring PAH (fluoranthene) regardless of the bioremediation approach. The results revealed that both natural attenuation and biostimulation could offer remarkable enhancement of up to 6.34% and 9.38% in PAH removals respectively after 8 weeks of incubation period. Overall, the results demonstrated that combined inorganic CA-enhanced MF treatment and bioremediation serves as a suitable strategy to enhance soil quality particularly to remediate soils heavily contaminated with mixtures of PAHs.
Ganoderma boninense is a fungus that can affect oil palm trees and cause a serious disease called the basal stem root (BSR). This disease causes the death of more than 80% of oil palm trees midway through their economic life and hexaconazole is one of the particular fungicides that can control this fungus. Hexaconazole can be applied by the soil drenching method and it will be of interest to know the concentration of the residue in the soil after treatment with respect to time. Hence, a field study was conducted in order to determine the actual concentration of hexaconazole in soil. In the present paper, a new approach that can be used to predict the concentration of pesticides in the soil is proposed. The statistical analysis revealed that the Exploratory Data Analysis (EDA) techniques would be appropriate in this study. The EDA techniques were used to fit a robust resistant model and predict the concentration of the residue in the topmost layer of the soil.
Phenolic chemicals with their very low taste and odour thresholds, high persistence and toxicity, are of growing concern as water pollutants. The compounds are known to exist in raw water as well as in treated water. The level of phenolic priority pollutants in water within the catchment area of the Linggi River Treatment Plant in Negeri Sembilan, Malaysia, which includes the Linggi river basin, was monitored. The 4-aminoantipyrin colourimetric method was used to determine total phenols whereas capillary column gas chromatography was used to determine the individual compounds. The results show that at most sampling stations, particularly those within the Seremban municipality, the level of phenols was found to exceed the recommended Malaysian standard of 2.0 μg/L(-1) for raw water. This is seen as the direct impact of industrial and urbanization of the area and clearly indicates the unhealthy state of the Linggi river. The results also indicate the need to improve the water quality if the river is going to be used as a source of raw water.
Linearity assessment as required in method validation has always been subject to different interpretations and definitions by various guidelines and protocols. However, there are very limited applicable implementation procedures that can be followed by a laboratory chemist in assessing linearity. Thus, this work proposes a simple method for linearity assessment in method validation by a regression analysis that covers experimental design, estimation of the parameters, outlier treatment, and evaluation of the assumptions according to the International Union of Pure and Applied Chemistry guidelines. The suitability of this procedure was demonstrated by its application to an in-house validation for the determination of plasticizers in plastic food packaging by GC.
Fats and oils in human diets are the main sources of essential fatty acids for the body. However, there is a mounting concern about the intake of foods containing trans fatty acids (TFAs) due to their deleterious effects on human. Thus, the accurate detection of fatty acids (FAs) and TFAs is needed to control and correct nutrition labeling in dietary fat samples. Accordingly, a method for the identification and quantification of FAs and TFAs in food fats by gas chromatography (GC) based on the extraction of lipids and derivatization using base catalyzed followed by trimethylsilyl-diazomethane (TMS-DM) was developed. The proposed method was evaluated to standard mixture of oleic acid (OA) (C18:1cis 9) and Elaidic acid (EA) (C18:1 trans 9) and its application to three samples of commercial margarines was demonstrated. Based on the results obtained, recovery values (R) from all the samples were close to 100%. Repeatability (RSD) values ranged between 0.78 and 2.47%, while Reproducibility (RSD) values ranged between 1.14 and 3.65%. Consequently, the proposed method is sensitive, accurate and suitable for FAs and TFAs analysis of food fats and oils and can be applied to nutritional, medicine and food studies.
Occurrence and distribution of organochlorine pesticides (OCPs), organophosphate pesticides (OPPs), and pyrethroid pesticides (PYRs) residues in the leafy vegetables were analyzed together with the soil samples using gas chromatography-electron capture detector. Edible tissues of vegetables showed detectable residues of these compounds indicating the influence of the conventional farms and nearby organic farms. In the vegetables, the OCPs concentrations were recorded as nd-133.3 ng/g, OPPs as nd-200 ng/g, and PYRs as nd-33.3 ng/g. In the soil, the OCPs concentrations were recorded as nd-30.6 ng/g, OPPs as nd-26.6 ng/g, and for PYRs as nd-6.7 ng/g. Bioconcentration factor (BCF) was higher for the OPPs (0.3) than the OCPs and PYRs (1.1). The OCPs concentration in the vegetables decreased in the following order: spinach > celery > broccoli > cauliflower > cabbage > lettuce > mustard. For OPPs, the concentration decreased in the following order: cauliflower > spinach > celery > cabbage > broccoli > lettuce > mustard and for PYRs as spinach > celery > lettuce > cabbage > broccoli. Principal component analysis indicates that the sources of these pesticides are not the same, and the pesticide application on the vegetables depends on the type of crop. There is a significant positive correlation between OPPs and the soil (r = 0.65) as compared to OCPs and PYRs (r = 0.1) as the vegetables accumulated OPPs more efficiently than OCPs and PYRs.
The objective of this paper is to study the effects of varying dietary levels of n-6 : n-3 fatty acid ratio on plasma and tissue fatty acid composition in rat. The treatment groups included control rats fed chow diet only, rats fed 50% soybean oil (SBO): 50% cod liver oil (CLO) (1 : 1), 84% SBO: 16% CLO (6 : 1), 96% SBO: 4% CLO (30 : 1). Blood samples were taken at day 15 of pregnancy, and the plasma and tissue were analyzed for fatty acid profile. The n-3 PUFA in plasma of Diet 1 : 1 group was significantly higher than the other diet groups, while the total n-6 PUFA in plasma was significantly higher in Diet 30 : 1 group as compared to the control and Diet 1 : 1 groups. The Diet 1 : 1 group showed significantly greater percentages of total n-3 PUFA and docosahexaenoic acid in adipose and liver tissue, and this clearly reflected the contribution of n-3 fatty acids from CLO. The total n-6 PUFA, linoleic acid, and arachidonic acid were significantly difference in Diet 30 : 1 as compared to Diet 1 : 1 and control group. These results demonstrated that the dietary ratio of n-6 : n-3 fatty acid ratio significantly affected plasma and tissue fatty acids profile in pregnant rat.
The present study investigates the detection of lard in cocoa butter through changes in fatty acids composition, triacylglycerols profile, and thermal characteristics. Cocoa butter was mixed with 1% to 30% (v/v) of lard and analyzed using a gas chromatography flame ionization detector, high performance liquid chromatography, and differential scanning calorimetry. The results revealed that the mixing of lard in cocoa butter showed an increased amount of oleic acid in the cocoa butter while there was a decrease in the amount of palmitic acid and stearic acids. The amount of POS, SOS, and POP also decreased with the addition of lard. A heating thermogram from the DSC analysis showed that as the concentration of lard increased from 3% to 30%, two minor peaks at -26 °C and 34.5 °C started to appear and a minor peak at 34.5 °C gradually overlapped with the neighbouring major peak. A cooling thermogram of the above adulterated cocoa butter showed a minor peak shift to a lower temperature of -36 °C to -41.5 °C. Values from this study could be used as a basis for the identification of lard from other fats in the food authentication process.
Degradation of amines is a significant issue allied to amine-based carbon dioxide (CO2) absorption in post-combustion CO2 capture. It becomes essential to have a detailed understanding of degradation products for advanced post-combustion CO2 capture technology. Identification and quantification of degradation products of amines help in practicability and environmental assessment of amine-based technology. Gas, liquid, and ion chromatographic techniques are the benchmark tools for qualitative and quantitative analyses of the amines and their derivatives. Among others, gas chromatography has been more in use for this specific application, especially for the identification of degradation products of amines. This review focuses on the critical elucidation of gas chromatographic analysis and development of methods to determine the amine degradation products, highlighting preparation methods for samples and selecting columns and detectors. The choice of detector, column, sample preparation, and method development are reviewed in this manuscript, keeping in view the industry and research applications. Furthermore, obtained results on the quantitative and qualitative analyses using gas chromatography are summarized with future perspectives.
Dioxins are a most toxic compound ever studied by human until today. Their significant health effects involved all ranges of age, including infants due to exposure to contaminated breast milk. The objective of the study was to appraise the status of dioxin contamination in breast milk among postnatal mothers live in urban and suburban areas in Klang Valley. It was conducted as a cross sectional study involving 101 postnatal mothers who came for their infant second hepatitis B vaccination. The samples were analysed using High Resolution Gas Chromatography (HRGC) following the USEPA Method 8290. About 70.3% of the samples were found detected with dioxin congeners. More suburban mothers have positive breast milk dioxins compared to urban mothers, 100.0% and 67.0% respectively. Significant associated factors include high fat daily intake (p=0.013), high milk daily intake (p= 0.044), high meat daily intake (p=0.001), body mass index more than 30 kg/m2 (p=0.005), and body fat % of more than 26% (p=0.046). In conclusion, amount daily intake of fat diet, meat, milk, body mass index and body fat are significant associated factors for the present of dioxins in breast milk among postnatal mothers in Klang Valley. More suburban mothers contain dioxins in their breast milk, which poses higher risk of health problems among their infants. A comprehensive study need to be conducted and regular followup need to be established in monitoring the future severity of maternal breast milk contamination to ensure the health of the next generations.