An automated approach for analysis of Fourier Transform Infrared (FTIR) spectra of edible oils

This paper reports a computational approach for analysis of FTIR spectra where peaks are detected, assigned and matched across samples to produce a peak table with rows corresponding to samples and columns to variables. The algorithm is applied on a dataset of 103 spectra of a broad range of edible oils for exploratory analysis and variable selection using Self Organising Maps (SOMs) and t-statistics, respectively. Analysis on the resultant peak table allows the underlying patterns and the discriminatory variables to be revealed. The algorithm is user-friendly; it involves a minimal number of tunable parameters and would be useful for analysis of a large and complicated FTIR dataset

Chemical characterization of humic substances occurring in the peats of Sarawak, Malaysia

The chemical characteristics of humic substances (HS) extracted from several samples of peat soils of Sarawak, Malaysia, were determined by size exclusion chromatography, FTIR, UV–Vis, acid–base titration, and elemental and total hydrolysable carbohydrate analyses. The results showed that the total acidity of these HS ranged between 5.8 and 8.3 meq/g, with a clear indication that the fulvic acid component contained more carboxylic groups compared to humic acids. A comparison with the literature data for HS occurring elsewhere showed that the tropical peat of Sarawak has higher carboxylic and phenolic contents, is richer in carbohydrate moiety and also is more oxygenated. The UV–Vis analyses gave a relatively high E4/E6 ratio, implying the prominence of aliphatic components. The relatively lower range of Mw further suggested the dominance of smaller-sized humic molecules. These structural attributes suggest that the local HS may exhibit a strong complexing capability and greater susceptibility to electrophilic cleavage by trihalomethane-forming agents

Assessment of a Physicochemical Indexing Method for Evaluation of Tropical River Water Quality

This paper attempts to evaluate the Malaysian water quality indexing method that has been criticized for its ineffectiveness. The indexing method is referred to as the Water Quality Index of the Department of Environment, Malaysia (DOE-WQI). This index was assessed against two other indices (River Ganga Index and Minimal Water Quality Index (WQImin)) and a modified DOE-WQI was also proposed. DOE-WQI and WQImin are physicochemical indices, whereas the River Ganga Index and modified DOE-WQI are indices with the inclusion of a microbiological parameter. The assessment was conducted based on the water quality of tropical rivers in Malaysia, with specific reference to Sarawak River and its tributaries. Water quality in terms of pH, dissolved oxygen, conductivity, turbidity, total suspended solids, biochemical oxygen demand, chemical oxygen demand, ammoniacal nitrogen, and fecal coliform count (FCC) was measured from 18 stations in December 2015, January 2016, and March 2016. Generally, the river was characterized with high FCC with the four indices significantly correlated. The results demonstrated the shortcomings of the existing DOE-WQI; the physicochemical index assigned water quality to a better class than its actual conditions without taking into consideration the FCC. © 2018 Siong Fong Sim and Szewei Elaine Tai

Multiple Self Organising Maps (mSOMs) for simultaneous classification and prediction: Illustrated by spoilage in apples using volatile organic profiles

Self Organising Maps (SOMs) have been modified and extended for various applications. This paper employed multiple SOMs (mSOMs) in supervised manner for multitasking involving simultaneous classification and prediction providing more information on a sample. This was demonstrated on the GC–MS dataset of apple spoilage where the volatile organic compounds (VOCs) of two groups of apples, control and inoculated, were monitored over 2 to 10 days. Multiple SOMs were used to determine whether a sample is a control or an inoculated apple and at the same time the spoilage day is predicted, i.e. how many days an apple has been left with or without inoculation. Multiple SOMs are different from traditional supervised SOMs; in mSOMs, samples are divided into classes for training on different maps. This approach of SOMs does not require optimisation of the scaling value however, it is important to make sure that the clustering qualities of mSOMs are comparable. Growing Self Organising Maps (GSOMs) was incorporated to automatically determine the suitable map size with comparable clustering qualities based on the mean quantization error. The findings demonstrated that mSOMs can be potentially applied for simultaneous analysis allowing more information to be retrieved on a sample reducing the overall computational time of an analysis

A curriculum-based laboratory kit for flexible teaching and learning of practical chemistry

Laboratory practical is an essential component for effective learning of science. To provide laboratory experience can be a challenge to some rural schools with limited laboratory facilities. The situation was exacerbated when schools were close due to the COVID pandemic. This paper reports a laboratory kit designed based on the Standard Curriculum for Secondary Schools in Malaysia (KSSM). The kit was evaluated by students and experienced teachers from town and rural schools. Pre- and post-test was conducted with the students before and after using the kit. A questionnaire was disseminated to appraise the students’ perceptions on practical learning. There was a significant improvement (p < 0.05) in the overall score of the post-test comparing to the pre-test. Both rural and town schools demonstrated a marked increase in the overall mean scores in the post-test. There was also improvement in affection for chemistry among students after using the kit. The practical kit can be deployed in schools with laboratory constraints and to be used outside the school settings. It was designed to be affordable, safe and environmental-friendly, providing individualized hands-on exposure

Study of the oviposition response of black soldier fly (BSF)in the presence of banana and pupal remains

Black soldier fly (BSF), Hermetia illucens, is an important beneficial insect.Numerous studies have been conducted to understand the oviposition behavior and preferences of BSF. This paper reports the effects of decomposition level of food and presence of pupal remnants on the oviposition responses of BSF. Cages comprising of four oviposition sites, housed with five male and female BSF were prepared. Gravid females were provided with equal opportunities to oviposit in two sites with ripened banana (mildly ripened (MR)or over-ripenedbanana(AR)) and two other sites with fresh banana (OV). Three replicates in clockwise replication design were set up. The presence of pupal cases inhigh, mediumand low abundance were studied. The number of eggs deposited at different sites were counted and expressed in percentageand oviposition attraction index (OAI). Gravid BSF females showed greater attraction to sites with over-ripened banana likely associating with the odor. BSF females also exhibited a preference for egg laying at sites with less pupae cases.Sites with the most abundance pupae cases were far less enticing as the pupae cases may deter the ovipositing BSF. The findings of this study is important for development of effective egg trapping and collection strategies in BSF farming

Reuse of nitric acid in the oxidative pretreatment step for preparation of humic acids from low rank coal of Mukah, Sarawak

Nitric acid is an effective material for production of humic acids. Nevertheless, it is an expensive item that renders the process unfavorable industrially. Study indicated that there was a possibility to reuse the nitric acid for oxidation however the resulting structures of humic acids was not studied. Therefore, the objective of this study was to investigate the chemical and spectroscopic properties of nitrohumic acids prepared with reused nitric acid. The coal sample was oxidized with 5%, 10% and 15% of nitric acid and subjected to extraction for nitrohumic acids. Concentration of nitric acid with the most yields was reemployed for another 2 cycles of oxidation. The chemical and spectroscopic properties of nitrohumic acids were evaluated. The results indicated that oxidation process generally improved the acidic functional properties of the nitrohumic acids with 10% nitric acid producing the most promising yield. The nitric acid was reused for extraction and the percentage yield remained good at an average of 78%. Structurally, the nitrohumic acids produced with the reused nitric acid demonstrated larger molecular size and fewer acidic functional groups suggesting lesser extent of structure fractionation

Assessing water quality of Murum Reservoir halfway through impoundment

This paper reports the water quality of Murum Hydroelectric Reservoir, eight months after impoundment of the dam. A total of nine stations were selected in the reservoir. Temperature, pH, dissolved oxygen (DO), biochemical oxygen demand (BOD5), chlorophyll-a and total suspended solids (TSS) were studied. The results showed that the water was warmer at 0.5 m depth. As the depth increased, temperature in the reservoir decreased in the range of 4.40°C to 7.35°C from 0.5 to 20 m depth. The concentration of DO dropped to zero at 4 - 6 m depth leading to anoxic level. pH at 0.5 m depth ranged from 6.40 to 7.20 and they were significantly higher (p<0.05) than those at 10 and 20 m. Chlorophyll-a at 0.5 m were in the range of 4.61 to 20.50 mg/L, relatively higher compared to 10 m and 20 m depths. The results obtained indicates that impoundment of Murum River generally caused water quality deterioration. In addition, this could be due to anthropogenic activities such as plantation and logging activities that are still going on within the catchment during the impoundment. Therefore, further continuous monitoring and investigation is required to determine the long-term water quality condition and identify factors that influence water quality in Murum Reservoir

A comparative evaluation on the oxidative approaches for extraction of humic acids from low rank coal of Mukah, Sarawak

Humic acid-based products are well marketed; nevertheless, these products remain unpopular in this region possibly due to the higher selling price resulted from the cost imposed on the imported products. For this reason, it is essential to identify the indigenous source of humic acids as the soil conditioner. Abundant of low rank coals are found in Mukah and the non-energy application of the source are largely unexplored. Preliminary study reported that chemical treatment with nitric acid could potentially increase the essential yield of humic acids from 20% to 85%. Nitric acid is an expensive item, which could add on to the cost, hence possibility of employing other oxidative approaches need to be evaluated. In this study, the humic acids were extracted from the low rank coal of Mukah with HNO3, H2O2 and KMnO4 oxidation and were compared in terms of yield, chemical and spectroscopical characteristics. Results indicated that H2O2 oxidation involved considerable weight losses upon oxidation render it unfavorable for production of humic acids. Potassium permanganate oxidation however was not recommended, as a substantial amount of inorganic compounds was introduced to the products and the essential yield generated was low. Nitric acid oxidation remains the choice of the process for extraction of humic acids as the weight losses involved was acceptable; the yield of humic acids obtained was high with characteristics of low ash content and high acidic functional groups

Spectrophotometric Analysis of Caffeine

The nature of caffeine reveals that it is a bitter white crystalline alkaloid. It is a common ingredient in a variety of drinks (soft and energy drinks) and is also used in combination with various medicines. In order to maintain the optimum level of caffeine, various spectrophotometricmethods have been developed.Themonitoring of caffeine is very important aspect because of its consumption in higher doses that can lead to various physiological disorders. This paper incorporates various spectrophotometricmethods used in the analysis of caffeine in various environmental samples such as pharmaceuticals, soft and energy drinks, tea, and coffee. Arange of spectrophotometric methodologies including chemometric techniques and derivatization of spectra have been used to analyse the caffeine