A method was proposed for the separation and determination of paraffin waxes in food by HPLC-evaporative light scattering detection (ELSD). A normal-phase column was used to separate nonparaffinic and paraffinic materials without resolving the latter into individual components. The t-test method was adopted for the evaluation of mean difference between response factors of n-alkanes in paraffin waxes on ELSD detector. No mean difference was obtained between response factors, which can be used for quantitative determination of paraffin waxes in food. The determination results obtained by HPLC-ELSD were compared with those by GC-MS. The linear range for the determination of paraffin waxes was in the range from 10 to 500 mg/L with a correlation coefficient of 0.9988, and the limit of detection was 1.0 mg/L. With the spiking level of 10, 50 and 100 mg/kg, the recovery ranged from 84.6% to 105.4% and the relative standard deviation ranging from 5.4% to 7.2%. The proposed method is simple, fast and sensitive.

Objective To investigate toxicity and teratogenic effect of Microula seed oil on embryo of rat.Methods 150 mature Wistar rats (100 females, 50 males) were selected with female∶ male = 2∶1 cage match. During the daily morning examination the sperm was discovered in the vagina as the zero day for conception.100 pregnant rats were randomly divided into 5 groups (n=20 in each group): treatment group (included 3 groups: to give Microula seed oil 2.5 g /kg, 5.0 g /kg, 10.0 g /kg body weight, ig, respectively), cyclophosphamide group(7 mg/ kg body weight, sc) and the edible oil group (to give dose, such as volume as Microula seed oil, ig). From the 7th day of pregnancy, the treatment group, the edible oil group were given intervention once a day for 10 days. From the 11th day of pregnancy cyclophosphamide group was given cyclophosphamide as intervention once a day, for 3 days. On the 20th day the pregnant rats were killed.Results The body weight of pregnant rats and the rate of live births were significantly higher in the Microula seed oil dose group than in the cyclophosphamide group (P<0.01), stillbirth rate and birth rate of absorption was significantly lower in the Microula seed oil dose group than in the cyclophosphamide group (P<0.01), and no significant difference from the edible oil group (P> 0.05); the fetal rat, body weight, body length, tail length in all groups of Microula seed oil was no significant difference from the edible oil group (P> 0.05). There was no malformation in appearance, viscera, bones in the treatment group and the edible oil group while there were 112 fetal rats with deformity in 140 in the cyclophosphamide group.Conclusion Microula seed oil at doses of 2.5 g /kg, 5.0 g /kg, 10.0 g /kg body weight had no significant role in the toxicity and teratogenicity on embryos of pregnant rats.

Nutrient agar medium was exposed in 0.085-0.092 T static magnetic fields for 12 h. Then we densities the optical densities at lamda = 600 (OD600) of Escherichia coli, Staphylococcus aureus and Bacillus subtilis in different culturing stage. The results were compared with those of control group in the normal geomagnetic field. The OD600 values of experimental groups of these three kinds of aerobes were significantly higher than those of control groups from 3h to 9h. However, after 11 h, there was no remarkable difference regarding the OD600 values between the two groups. The dissolved oxygen content of nutrient agar medium was determined by microtitration. The dissolved oxygen of nutrient agar medium under static magnetic for 12h increased 15% in average and there was significant difference when compared with the control. The results showed that the ferro-magnetic fields increased the dissolved oxygen content of nutrient agar medium significantly. These findings suggest that the effects of static magnetic fields on Escherichia coli, Staphylococcus aureus and Bacillus subtilis are related to the dissolved oxygen.
Bacillus subtilis ; growth & development ; radiation effects ; Culture Media ; radiation effects ; Escherichia coli ; growth & development ; radiation effects ; Magnetic Fields ; Staphylococcus aureus ; growth & development ; radiation effects