Saiful Irwan Zubairi

Effect of Nano ZnO on the Optical Properties of Poly(vinyl chloride) Films

Optical properties of pure and doped poly(vinyl chloride) (PVC) films, prepared by using casting technique, with different nanosize zinc oxide (ZnO) concentrations (1–20) wt% have been studied. Parameters such as extinction coefficient, refractive index, real and imaginary parts, Urbach energy, optical conductivity, infinitely high frequency dielectric constant, and average refractive index were studied by using the absorbance and transmittance measurement from computerized UV-visible spectrophotometer (Shimadzu UV-1601 PC) in the spectral range 200–800 nm. This study reveals that the optical properties of PVC are affected by the doping of ZnO where the absorption increases and transmission decreases as ZnO concentration increases. The extinction coefficient, refractive index, real and imaginary parts, infinitely high frequency dielectric constant, and average refractive index values were found to increase with increasing impurity percentage. The Urbach energy values are found to be decreasing with increasing ZnO concentration. The optical conductivity increased with photon energy after being doped and with the increase of ZnO concentration.

Development of a New Binary Solvent System Using Ionic Liquids as Additives to Improve Rotenone Extraction Yield from Malaysia Derris sp.

Rotenone is one of the prominent insecticidal isoflavonoid compounds which can be isolated from the extract of Derris sp. plant. Despite being an effective compound in exterminating pests in a minute concentration, procuring a significant amount of rotenone in the extracts for commercialized biopesticides purposes is a challenge to be attained. Therefore, the objective of this study was to determine the best ionic liquid (IL) which gives the highest yield of rotenone. The normal soaking extraction (NSE) method was carried out for 24 hrs using five different types of binary solvent systems comprising a combination of acetone and five respective ionic liquids (ILs) of (1) [BMIM] Cl; (2) [BMIM] OAc; (3) [BMIM] NTf2; (4) [BMIM] OTf; and (5) [BMPy] Cl. Next, the yield of rotenone, % (w/w), and its concentration (mg/mL) in dried roots were quantitatively determined by means of RP-HPLC and TLC. The results showed that a binary solvent system of [BMIM] OTf + acetone was the best solvent system combination as compared to other solvent systems ( ). It contributed to the highest rotenone content of 2.69 ± 0.21% (w/w) (4.04 ± 0.34 mg/mL) at 14 hrs of exhaustive extraction time. In conclusion, a combination of the ILs with a selective organic solvent has been proven to increase a significant amount of bioactive constituents in the phytochemical extraction process.

Kinetics Extraction Modelling and Antiproliferative Activity of Clinacanthus nutans Water Extract

Clinacanthus nutans is widely grown in tropical Asia and locally known “belalai gajah” or Sabah snake grass. It has been used as a natural product to treat skin rashes, snake bites, lesion caused by herpes, diabetes, fever, and cancer. Therefore, the objectives of this research are to determine the maximum yield and time of exhaustive flavonoids extraction using Pelegs model and to evaluate potential of antiproliferative activity on human lung cancer cell (A549). The extraction process was carried out on fresh and dried leaves at 28 to 30°C with liquid-to-solid ratio of 10 mL/g for 72 hrs. The extracts were collected intermittently analysed using mathematical Pelegs model and RP-HPLC. The highest amount of flavonoids was used to evaluate the inhibitory concentration (IC50) via 2D cell culture of A549. Based on the results obtained, the predicted maximum extract density was observed at 29.20 ± 14.54 hrs of extraction (t exhaustive). However, the exhaustive time of extraction to acquire maximum flavonoids content exhibited approximately 10 hrs earlier. Therefore, 18 hrs of extraction time was chosen to acquire high content of flavonoids. The best antiproliferative effect (IC50) on A549 cell line was observed at 138.82 ± 0.60 µg/mL. In conclusion, the flavonoids content in Clinacanthus nutans water extract possesses potential antiproliferative properties against A549, suggesting an alternative approach for cancer treatment.

Polyesters Based on Linoleic Acid for Biolubricant Basestocks: Low-Temperature, Tribological and Rheological Properties.

Presently, plant oils which contain high percentage of linoleic acid 1 are perceived to be a viable alternative to mineral oil for biolubricant applications due to their biodegradability and technical properties. In order to get biodegradable lubricant, triester derivatives compounds (1–5) were synthesized and characterized. The processes involved were monoepoxidation of linoleic acid 2, oxirane ring opening 3, esterification 4 and acylation 5. The structures of the products were confirmed by FTIR, 1H and 13C-NMR and LC-MS. The results that showed lowest temperature properties were obtained for triester 5, with a pour point value (PP) of -73°C, highest onset temperature (260°C) and lowest volatility at 0.30%. Viscosity index (VI) increased for the ester’s synthetic compounds (2, 3, 4, 5), while the PP decreased. This behavior is the result of the increase of the chain length of the branching agents. Triester based linoleic acid has improved properties such as low-temperature and tribological properties. These results will make it feasible for plant oil to be used for biolubricants, fuels in chain saws, transmission oil and brake fluid.

Alcohol based-deep eutectic solvent (DES) as an alternative green additive to increase rotenone yield

Deep eutectic solvents (DESs) are basically molten salts that interact by forming hydrogen bonds between two added components at a ratio where eutectic point reaches a melting point lower than that of each individual component. Their remarkable physicochemical properties (similar to ionic liquids) with remarkable green properties, low cost and easy handling make them a growing interest in many fields of research. Therefore, the objective of pursuing this study is to analyze the potential of alcohol-based DES as an extraction medium for rotenone extraction from Derris elliptica roots. DES was prepared by a combination of choline chloride, ChCl and 1, 4-butanediol at a ratio of 1/5. The structure of elucidation of DES was analyzed using FTIR, 1H-NMR and 13C-NMR. Normal soaking extraction (NSE) method was carried out for 14 hours using seven different types of solvent systems of (1) acetone; (2) methanol; (3) acetonitrile; (4) DES; (5) DES + methanol; (6) DES + acetonitrile; and (7) [BMIM] OTf + acetone. Next, the yield of rotenone, % (w/w), and its concentration (mg/ml) in dried roots were quantitatively determined by means of RP-HPLC. The results showed that a binary solvent system of [BMIM] OTf + acetone and DES + acetonitrile was the best solvent system combination as compared to other solvent systems. It contributed to the highest rotenone content of 0.84 ± 0.05% (w/w) (1.09 ± 0.06 mg/ml) and 0.84 ± 0.02% (w/w) (1.03 ± 0.01 mg/ml) after 14 hours of exhaustive extraction time. In conclusion, a combination of the DES with a selective organic solvent has been proven to have a similar potential and efficiency as of ILs in extracting bioactive constituents in the phytochemical extraction process.

Characterizing the Deacidification Adsorption Model of Organic Acids and Phenolic Compounds of Noni Extract Using Weak Base Ion Exchanger

Although noni (Morinda citrifolia L.) has been used to treat a broad range of diseases, many people avoid consuming the fruits because of its unpleasant odor caused by organic acids. Even though ion exchange resins were able to reduce the odor, it also reduced beneficial antioxidant compounds. Thus, to preserve antioxidants (phenolic compounds) during deacidification, it is important to characterize the interaction of ion exchange resin with both organic acids and phenolic compounds. Adsorption capacities of organic acids and phenolic compounds commonly found in the noni fruit were conducted onto Amberlite IRA 67 resin. The phase contact time to reach equilibrium for octanoic acid and hexanoic acid compounds was 326.86 and 160.72 min, respectively. The values of initial adsorption rate, , and adsorption extent, , decreased with the increase of initial concentration for all compounds studied. Results for all the compounds studied fitted well to the Langmuir model. The effect of pH in adsorption capacity of the actual system (noni juice) has been applied based on the model system studied.

Physicochemical Characterization of Biofluid Metabolites from Liquid Residual of Tuna Fish (Euthynnus affinis) throughout Refrigerated Storage Condition

The cold storage condition and use of chemical treatment to preserve the fish appearance sometimes cause difficulties to the consumers to estimate the freshness of fish in the market. However, during fish deterioration, some compound is released or formed due to microbial and biochemical process. Identification of released compound during fish spoilage is a crucial step in understanding the degree of spoilage. This study characterizes the physicochemical changes of metabolites biofluids from liquid residual of tuna fish (Euthynnus affinis) during refrigerated storage condition. Tuna fish were kept in ice at 0°C and stored in cold room (~4°C) for seven days in order to study the changes in fish freshness and loss of quality through the storage period. Liquid residual of fish was collected at 0, 1, 2, 3, 4, 5, 6, and 7 days of storage. LC-MS/MS analysis was carried out to determine the possible dominant compound which was later identified as creatine and phenylalanine. Quantification of creatine and phenylalanine using HPLC with UV detector found that creatine and phenylalanine increased significantly up to day 4 and day 5 upon storage time for creatine and phenylalanine, respectively ( ). The liquid residual pH increased from 6.5 on day 0 to 7.5 on day 7 ( ). Changes in chemical compounds were supported with physical analysis on gills colour of spoilage fish. and values decreased with storage time from 41.08 to 24.76 and 18.34 to 10.40, respectively, while value increased from 3.80 to 0.46 ( ). The finding of biofluid derived compounds was found as useful and alternative indicators of fish freshness in later study on the development of optical biosensor.

Synthesis and characterization of neopenthyl glycol diolete as a biolubricant base

Neopenthyl glycol is a polyol that is potential to be a good base for biolubricant via esterification process with oleic acid. In this study, esterification reaction between NPG and oleic acid has been carried out in the presence of 2% w/w sulphuric acid (based on weight of FA) as a catalyst to produce NPG dioleate. The temperature for this reaction was 130°C and the molar ration of oleic acid: NPG was 2:1. The time for the reaction was 4 hours. The presence of the ester in the product was confirmed through Fourier Transform Infrared (FTIR) and followed by NPG diolete composition determination via Gas Chromatography (GC-FID). The structure of NPG diolete was confirmed using both proton and carbon Nuclear Magnetic Resonance (1H-NMR and 13C-NMR) analysis. 100% NPG diolete were obtained in this study. The viscosity index of the product is 227, flash point 200°C, pour point −44°C and oxidative stability 177°C.

Saponin Bitterness Reduction of Carica papaya Leaf Extracts through Adsorption of Weakly Basic Ion Exchange Resins

Carica papaya that belongs to Caricaceae family has long been known as a traditional medicine for dengue fever, as well as for anticancer and antiinflammatory studies following identification of beneficial phytochemicals such as saponins in the leaves. Unfortunately, the compound has been known to induce a bitter taste in the leaf extract for human consumption, making them unpopular and nonconsumer friendly. Thus, this study aims to observe the potential adsorption of saponin compound from C. papaya leaves using ion exchange resins as an adsorbent for the reduction of bitter-taste-inducing saponins. This study uses three types of weakly basic ion exchanging resins, namely, Amberlite IRA-67, Diaion WA30, and Diaion WA21J, at different adsorbent doses of 5% (w/v) and 10% (w/v). The Peleg model suggests that the extraction of saponins from C. papaya leaves lasted for 12.50 hours yield a maximum amount of saponins, 9.31 mg/g. Further study shows that there is a significant difference ( ) of saponin adsorption percentage between these three types of resins. The Diaion WA30 resin showed the highest percentage of adsorption at 87.83% (w/w) as compared to the other two 5% (w/v) loaded resin. The 10% (w/v) resin-loaded Diaion WA30 demonstrated the highest overall adsorption capacity as much as 97.59% (w/w) with the shortest exhaustive time of 4.99 hours. The overall acceptance of samples in sensory evaluation treated with ion exchange resins gave good response in which the sample treated with 10% (w/v) resin-loaded Diaion WA30 demonstrated the highest overall acceptance in parallel with having the lowest bitterness score as compared to other samples and fresh samples (untreated). The Langmuir constant (RL) was less than one (0.167–0.398), indicating the adsorption of saponins onto Diaion WA30 was favourable.

Effect of plasma treatment (He/CH4) on glass surface for the reduction of powder flux adhesion in the spray drying process

A 50Hz glow discharge He/CH4 plasma was generated and applied for the modification of glass surface to reduce powder adhesion on the wall of spray dryer. The hydrophobicity of the glass samples determined by the water droplet contact angle and adhesion weight on glass, dependent on the CH4 flow rate and plasma exposure time. There was a peak that appeared at 1470 cm-1 on the surface of treated glass indicating the presence of CH3 groups from ATR-FTIR data. Surface morphology analysis using scanning electron microscopy (SEM) showed changes of roughness in the surface-treated glass. The presence of alkyl group (CH3) that deposited on the glass surface is one of the factors that contribute to the increase in the surface roughness. The surface roughness will reflect the value of contact angle where hydrophobic surface are rougher compared to hydrophilic surface. The plasma treatment could enhance the value of the contact angle and thus reduced the adhesion on the spray dryer glass surface.A 50Hz glow discharge He/CH4 plasma was generated and applied for the modification of glass surface to reduce powder adhesion on the wall of spray dryer. The hydrophobicity of the glass samples determined by the water droplet contact angle and adhesion weight on glass, dependent on the CH4 flow rate and plasma exposure time. There was a peak that appeared at 1470 cm-1 on the surface of treated glass indicating the presence of CH3 groups from ATR-FTIR data. Surface morphology analysis using scanning electron microscopy (SEM) showed changes of roughness in the surface-treated glass. The presence of alkyl group (CH3) that deposited on the glass surface is one of the factors that contribute to the increase in the surface roughness. The surface roughness will reflect the value of contact angle where hydrophobic surface are rougher compared to hydrophilic surface. The plasma treatment could enhance the value of the contact angle and thus reduced the adhesion on the spray dryer glass surface.