يساعد الكتاب في فهم ألاسس العملية للكيمياء التحليلية بطريقة سهلة الفهم والاستيعاب arabic 57 English 0
د رجب علي المختار عيسي(1-2019)

Modern improvements in Fourier transform infrared spectroscopy instrumentation spread out the application of this technique to the field of food research. This study is focused to evaluate the efficiency of FT-IR spectroscopy in order to assess the Libyan virgin olive oil adulteration with cheaper vegetable oils: sunflower oil and corn oil. Taking a closer inspection to different regions of recorded IR spectra of both pure oil sample (virgin olive oil, sun flower oil, corn oil) and their mixture: It is noticed that an absorbance shift was identified at about 3000 cm-1 due to the C-H stretching vibration of the cis-double bond proved to be reliable index for assessing of virgin olive oil adulteration by vegetable oil addition. Also, the absorbance at about 3008 cm-1, characteristic to the oils with a high saturated fatty acids content and short carbohydrate chain, recorded appreciable changes by increasing of vegetable oil percent added in virgin olive oil. Based on the calibration curve (absorbance versus percent of vegetable oil added in virgin olive oil), it is possible to determine the degree of virgin olive oil adulteration. A significant positive correlation for both adulterant oils (R2 > 0.97) at wavenumber 3008.3 cm-1 was observed in our study. Our data demonstrated that FT-IR spectroscopy proved to be a valuable tool to identify the differences recorded in oil samples spectra and finally, to appreciate the degree of virgin olive oil adulteration
Ragiab Ali Mokhtar Issa(1-2018)

This report is based on the assessment of four heavy metals: lead, chromium, nickel, and copper, in thirty-two roadside soil samples, one of which was a virgin soil, in Zawia City, Libya. During spring 2019, soil samples were collected from five sites along Jamal Street starting from the old university building to Al-Shuhadaa Square. The atomic absorption spectrometer Perkin Elmer AAnalyst 400 was used in this study using absorption mode, except for the use of Cu emission mode due to the unavailability of the Cu lamp. Results showed that the highest concentrations of the investigated elements were: 36 mg/kg for Pb, 15.6 mg/kg for Cr, 8.3 mg/kg for Ni, and 50 mg/kg for Cu. These values are in agreement with the allowable values of heavy metal concentration of soils in some European countries (i.e. Austria, Germany, and France). However, the concentration values for Pb, Cr, Ni, and Cu were 5.2, 2.9, 2.3, and 7.8 fold higher, respectively, than that of the virgin soil sample collected about 10 km away from the city centre. The sample preparation method used in this work was demonstrated to be suitable, showing acceptable recovery values (R%) of 94.6%, 81.9%, 87.6%, and 90.7% for Pb, Cr, Ni, and Cu, respectively.
Ragiab A M Issa(4-2020)