07 February 2011

Dept of Chemistry by Tarmizi

JAN 03, 2011 – FEB 02, 2011

At this Department of Chemistry, I was placed at the Mycotoxin Service Centre. This centre is also related to the food because the analysis has done to the mycotoxin that present in the food such as peanuts, grains and milk. The mycotoxins are new and interesting things that I must learned at here. The analyses that always do are to detect the Aflatoxin (B and G) in the peanut product, Aflatoxin (M1) in the milk, Ochratoxin A (OTA) and Zearalenone (ZON) in the corn, barley, grain and wheat flour. The food samples are basically come from Ministry of Health, Hospital/Department of Health, and Department of Veterinary.

The first analysis was doing is Determination Organophosporus (OP) in Fruits and Vegetables QuEChERS Method. This experiment is doing to identify the level of OP that use in the fruits/vegetables by running
the extract of sample using Gas Chromatography (GC). Then, the second analysis was doing is Determination of the Aflatoxin B and G in the Peanuts based product. There are eight sample that must be to extract such as kacang tumbuk, peanut butter, kacang manis, pau kacang and others including two spiking sample that must spike with Afla BG standard 1ppm and 5 ppm which must be running using the Fluorescence Detector High Perfomance Liquid Chromatography (HPLC). Based on the Food Act 1983, the maximum level that allowed in microgram per kilogram for the peanuts (Alfatoxin B and G) is 15, milk (Alfatoxin M1) is 0.5 and others finish product that have mycotoxins is 5.

My supervisor, Mr. Nor Shifa Bin Shuib give me the two project that I must have done during my industrial training. The first project is “Determination of Deoxynivalenol (DON) in the Raw Wheat, Wheat Flour
and Wheat Based Products. The selected molds that produce DON is Fusarium graminearium and the food susceptible to contamination are wheat, corn, barley, malted barley and oat. When the people consume
the high level of this DON toxin the effect to the health is damage to digestive tract, bone marrow, spleen, weight loss, vomiting and fees refusal.

 So, the preparation to this project was starting from week two until week six. Before analyze DON by using the Ultra-Violet Detector HPLC, there are some procedure that must be follow. Firstly, the Ultra-
Violet Spectrophotometer must be calibrating to determine the Correction Factor (CF) in the range 0.95-1.05. When measuring of CF in that range, the calibration of DON standard was doing to identify the
absorbance and maximum wavelength (highest peak) which using in the set up the wavelength at the UV Detector HPLC. The absorbance can be use to measure the concentration of the DON standard before diluted with Acetonitrile (ACN) until 10ppm and 20ppm.

The samples that I was collected are wheat grain, barley, oat, yellow noodles, instant noodle, and wheat flour. There are two procedures to determine the DON in food which are extraction and the Immunoaffinity
Column (IAC). For the extraction method, the 25g sample was added with the 5 g Polyethylene Glycol (PEG) and 100ml purified water. The mixture was blended for 1 minute and filter via the filter paper and
then, via the micro fiber filters paper. For the IAC, the 2ml of extract sample was pipette into the column and wash with 5ml purified water. The excess water removes and pushes the air until the column dry. Then, 1ml of HPLC Grade Methanol was pipette into the column to collect elute into the vial. The vial was drying using the nitrogen gas and pipette the 1 ml Injection Solvent [Water (9): ACN (1)] into the vial, ad then shake the vial homogenize.

Before run the sample, the DON standard must be prepared first. The 0.5ml of 20ppm DON standard is pipette into vial and dry using the nitrogen. Then, 1 ml of IS was added into vial and shake completely.
The DON standard is ready to run and determine the peak of the standard. After determine the peak of DON standard, the vial of food samples can be run using the UV detector HPLC. The retention time for
DON standard is at 5.24 minutes. From the foods samples that run, the entire samples show no peak (negative) at this retention time. I assume that the DON in the sample are absent or present in little
amount that cannot be detected using the HPLC because no sensitive. There are some precaution step protection equipment that must be follow up because there are handling the solvent and chemical compound
when doing the analysis such as wearing the gloves, mask, use the fume cupboard and others.

At here, I was learned the application of the HPLC, UV Spectrophotometer and others equipments that used for the analysis. The all staff at this department is nice and friendly (especially girl..huhu) to teach me the new and the procedure that I didn’t know to do. There are no foreign workers especially “abg la”…just have the sweet black skin people (kulit hitam manis) because the area of “anak mami”…huhu…

Please wait for the next post in my second project..=D