Haloacetic acids (HAAs) are one of the most common disinfection by-products formed during chlorination of drinking water. An analytical method involving solid phase extraction (SPE) followed by gas-chromatograph mass-spectrometry (GC-MS) was developed and optimized using experimental design to determine the HAAs in water. Selectivity, percent recovery, and detection limit studies were carried out on a Silia-SAX (Trimethyl ammonium chloride) SPE. Under optimized conditions, average recoveries for nine HAAs spiked in drinking water samples range from 69.2% to 108.2 %. The relative
standard deviation (RSD) data were found to range from 2.5 % to 12.5% based upon five repeat recovery experiments and detection limit range of 0.16 to 0.009μg/l were obtained. On this basis, SPE was studied as a possible alternative to liquid-liquid extraction (LLE) for the analysis of HAAs in water. The performance of the SPE-GC-MS with actual water samples was tested.
Loji rawatan kumbahan (STP) sedia ada khususnya di Malaysia tidak direka untuk menyingkirkan bahan farmaseutik yang
tergolong dalam kategori bahan cemar baru muncul. Oleh kerana farmaseutik yang hadir dalam persekitaran akuatik
ialah pada kepekatan yang sangat rendah iaitu dalam julat bahagian per bilion dan trilion, satu kaedah pengekstrakan
dan analisis yang peka perlu dibangunkan. Dalam kajian ini, kaedah analisis berdasarkan pengekstrakan fasa pepejal
(SPE) diikuti dengan kromatografi cecair-spektrometri jisim masa penerbangan (LC-TOF-MS) menggunakan mod pengionan
secara semburan elektro positif telah berjaya dibangunkan untuk menentukan kehadiran sepuluh farmaseutik terpilih
dalam air kumbahan dan air sungai. Farmaseutik yang dikaji termasuk acetaminophen, theophylline, caffeine, metoprolol,
sulfamethoxazole, carbamazepine, prednisolone, ketoprofen, norgestrel dan simvastatin. Kaedah SPE menggunakan
langkah pengekstrakan tunggal yang menggunakan isi padu sampel yang rendah sebanyak 100 mL dan pelarut elusi
yang minimum telah berjaya dicapai. Peratus perolehan semula untuk kesemua farmaseutik dalam sampel air sungai
berada dalam julat 54-99% manakala bagi sampel efluen STP pula berada dalam julat 57-96%. Jangka masa analisis
LC-TOF-MS termasuk masa imbangan adalah selama 25 min dengan menggunakan suntikan sampel 20 μL. Prosedur SPE
bersama-sama dengan kaedah analisis yang telah dibangunkan menghasilkan had kuantifikasi (LOQ) dalam lingkungan
0.031-0.882 μg/L untuk sampel STP dan 0.030-0.926 µg/L untuk sampel air sungai.
Aluminium in drinking water comes from natural sources and the alum used as coagulant in the water treatment process. Exposure to aluminium has been implicated in dialysis dementia, Parkinson and Alzheimer’s disease. Drinking water containing aluminium was considered to be one of the main sources of Al intake into human body. For this reason, the removal of aluminium from drinking water is vital to our health. In this study, removal of aluminium was carried out by using a chelating resin. To achieve the purpose, two chelating resin iontosorb oxin (IO) and polyhydroxamic acid (PHA) were used. The effects of concentration, pH, stirring time and resin amount was investigated. The concentration range varied between 10 and 500 ppb, pH range was between 2 and 12, stirring time between 5 and 60 minutes, and resin amount between 100 and 1500 mg. The optimum conditions of these resins were determined in a batch system. The results obtained showed that the optimum condition to remove aluminium for polyhydroxamic acid and iontosorb was pH 5-8 and pH 4-9; concentration range between 50-500 ppb, and 150-500 ppb, resin amount 200 mg and the stirring time was 20 minutes, respectively.
Malaysia has introduced a new Time of Use (ToU) tariff scheme known as Enhanced ToU (EToU) for
commercial and industrial customers. EToU is a more detailed pricing scheme where one day time frame
is divided into six period blocks as compared to only two period blocks in the existing ToU. Mid-peak
tariff is introduced to the existing peak and off-peak tariff. Off-peak rate for EToU is significantly lower
than the existing off-peak rate but the peak rate is much higher. EToU is designed to motivate users to
reduce their consumption during peak hours or shift the load to mid-peak or off-peak hours, which if
done correctly can reduce the electricity bill while maintaining electricity consumption. This new EToU
scheme will benefit consumers if they are able to shift consumption from peak-hours into mid-peak
or off-peak hours. This paper assesses the amount of load shifting that is required based on customers’
load profile and EToU rates. The load profile data of an office building in Putrajaya, Malaysia is used
as a case study.
A survey was conducted to investigate the level of consumption of ‘ulam’ in Selangor State among 252 adults (> 17 years) (male 28.6%, female 71.4%) of major ethnics (Malays-51.6%; Chinese-30.5%; Indians-17.5%) with the mean age of 42.7 ± 13.9 years. Consumption data were collected using 24 hours duplicate samples together with questionnaire on perceptions of ‘ulam.’ Results showed that ‘ulam’ was preferred by majority of the subjects (82.1%), especially amongst Malays (92.3%). A total of 52% of the subjects consumed partially or boiled ‘ulam.’ Factors that affect their preferences on ‘ulam’ were the perception of therapeutic effects of the ‘ulam’ towards health, its good taste and unique
aroma. The most consumed ‘ulam’ were cucumber (Cucumis sativus) (60.6%) ‘kacang botol’ (Psophocarpus tetragonolobus) (33%), Indian pennywort (Hydrocotyle asiatica) (31.5%), lettuce (Lactuca sativa) (27.6%), ‘petai’ (Parkia speciosa) (29%) and ‘ulam raja’ (Cosmos caudatus) (21.9%). The most preferred partially or boiled ‘ulam’
were tapioca shoot (Manihot esculenta) (31.5%), ocra (Hibiscus esculentus) (12.5%) and ‘jantung pisang’ (Musa sapientum) (20.1%). There was no significant difference (P > 0.05) amongst the three different ethnic groups on the consumption of ‘ulam’ and the median for total intake per day was within the range of 30-39 g/day. Ulam is a potential
source for increasing vegetable consumption to meet recommendation by World Health Organization (WHO), which is 400 g per day.
Keywords: Adults; perception; ‘ulam;’ Selangor State
The big challenge for the detection of pharmaceutical residues in water samples is the type of ionization mode in
terms of positive or negative ionization which plays an important role to identify and quantify the analytes using liquid
chromatography/mass spectrometry. An analytical method was applied to analysis of gliclazide (diabetic drug) in surface
water and wastewater from sewage treatment plants and hospitals. The proposed analytical method allows simultaneous
isolation and concentration procedure using solid phase extraction (Oasis HLB) prior to separation using high-performance
liquid chromatography. The detection and confirmation was achieved by applying time-of-flight analyzer. The limits of
quantification were as low as 1.4 ng/L (deionized water), 4 ng/L (surface water), 27 ng/L (hospital influent), 10 ng/L
(hospital effluent), 6 ng/L (sewage treatment plant effluent) and 21 ng/L (sewage treatment plant influent), respectively. On
average, good recoveries of higher than 87% were obtained for gliclazide in the studied samples. The proposed method
successfully determined and quantified gliclazide in surface water and wastewater. The results showed that gliclazide
is a persistent compound in sewage treatment effluents as well as in the recipient rivers. Gliclazide was detected in all
samples and the highest concentration was 130 ng/L in influent of sewage treatment plant.