The aim of this study was to examine the influence of fertilization on nitrate, nitrite, and vitamin C contents in vegetables. All seedlings (mustard, bokchoy, spinach, and lettuce) were grown in the greenhouse in polybags with organic and inorganic fertilizers. Nitrite was derivitized with sulfanilic acid and N-(1-naphthyl) ethylenediamine dihydrochloride in acetic acid solution, then absorbance measured by spectrophotometer at 540 nm. Nitrate reduced to nitrite by adding zincum powder in acidic condition, then determined as nitrite. Vitamin C was titrated with 2,6-dichlorophenol indophenol.The study show that the influence of organic fertilizers increased nitrate, nitrite and vitamin C contents with increasing doses. Inorganic fertilizers was found to be more influential to increase nitrite and nitrate contents, but decreased vitamin C with increasing doses.This findings suggest that inorganic fertilizers more effective to increase nitrate and nitrite contents compared to organic fertilizers. Organic fertilization increased vitamin C, but inorganic fertilization decreased.

Antibiotics are commonly used as food additives in broiler farms and their use tends to be excessive regardless and incorrect that can leave some antibiotic residues in chicken meat. The aimed of this study was to analyze on  antibiotic residues level amoxicillin and tetracycline in chicken meat sold in Medan. The antibiotic residues analysis was conducted by extracting the antibiotic from chicken meat with water and acetonitrile (2:8, v/v) and detected by high performance liquid chromatography-mass spectrometry detector using C-18 column (4.6 mm i.d., length 30 mm, particle size 1.8 µm) at 35 oC, with the mobile phases,  0.1 % formic acid solution in water and 0.1 % formic acid solution in methanol with gradient elution technique at a flow rate of  0.5 ml/minute. The result exhibited that the chicken meat that were collected from five  markets  in Medan apparently contained antibiotic residues  tetracycline . The level of  tetracyclin residue in chicken meat was  0.1157-1.4436 µg/g, which exceed the maximum level  for tetracyclin residue allowed in foodstuffs of animal origin which is 0.1 ug/g.   Keywords: residue, antibiotic, amoxicillin, tetracycline, chicken meat

Objective: This research is aimed to investigate that durian seed gum is potential as an excipient in topical drug delivery. Durian seed gum is isolated from low-cost source and usually discarded.Methods: A certain amount of durian seed gum was isolated and characterized by scanning electron microscopy energy dispersive X-ray (SEM-EDX) and infrared spectrophotometer. The isolation method is divided into centrifuge and heating method, and the results of both methods are compared in their ability to form a gel and their evaluation.Results: The infrared spectra of durian seed gum by centrifugal method indicate the presence of -OH, -COOH, -CH groups, and the addition of C=O and ester groups on the heating method, i.e., at wave number 1726.22 cm−1. SEM-EDX shows the form of hollow surface particles, and the elements contained are C, O, K, Cl, and Mg. Durian seed gum of both methods formed a gel with boiling water at a concentration of 5% giving transparent and non-flowing results.Conclusion: Durian seed gum by the heating method is a low-methoxyl pectin compound because it is extracted at an alkaline pH. Durian seed gum can form a gel and complete the gel evaluation requirements.

Vegetables are the main sources of nitrate and nitrite in food. The presence of nitrate and nitrite at a high level may cause a negative impact on health, because nitrite and nitrate when reduced to nitrite, may react with alkylamine to form carcinogenic nitrosamine. The influence of temperature and time of storage on nitrite, nitrate, and vitamin C contents in vegetables were investigated in this study. The vegetables were sweet mustard, bokchoy, spinach and lettuce obtained from a local market. Samples were stored at ±25 C and ±5 C. Analysis of nitrite, nitrate, and vitamin C was conducted in fresh samples, after storage for 24 and 48 hours. Nitrite was analyzed by spectrophotometry at 540 nm. Nitrate reduced into nitrite with Zn in acidic conditions and then analyzed as nitrite. Vitamin C was analyzed by titration with 2.6-dichlorophenolindophenol. During storage, nitrite and nitrate increased, while vitamin C decreased. Nitrite and nitrate content in fresh samples were 15.22 and 22.46 mg/kg (sweet mustard), 12.57 and 6.55 mg/kg (bokchoy), 20.26 and 90.60 mg/kg (spinach), 18.77 and 32.68 mg/kg (lettuce), respectively. Vitamin C content in fresh samples was 101.15 mg/100g (mustard), 92.17 mg/100g (bokchoy), 88.95 mg/100g (spinach), 40.03 mg/100g (lettuce). After storage for 48 hours at ±25 C, nitrite and nitrate increased 44.97% and 53.19% (mustard), 46.18% and 62.59% (bokchoy), 43.86% and 16.48% (spinach), and 41.05% and 47.09% (lettuce), respectively. Vitamin C decreased 67.57% (mustard), 24.68% (bokchoy), 81.25% (spinach), and 79.74% (lettuce). Storage at ±5 C, showed that nitrite and nitrate increased 27.54% and 35.08% (mustard), 13.75% and 43.51% (bokchoy), 19.59% and 10.60% (spinach), 19.85% and 25.16% (lettuce), respectively. Vitamin C decreased 30.88% (mustard), 6.05% (bokchoy), 60.92% (spinach), and 74.94% (lettuce). During storage, nitrite and nitrate increased more significantly at ±25 C than ±5 C while vitamin levels C decreased and were more effective at 25 C than 5 C.

Objective: This study aimed to develop spectrophotometry ultraviolet (UV) method by area under curve (AUC) to determine the levels of isoniazid (INH) and pyridoxine hydrochloride (PDX) in commercial tablets. Methods:Spectrophotometry UV method by AUC tested is carried out by optimizing the type of solvent, methanol, mixture of methanol, and phosphate buffer pH 4, pH 5, and pH 6 at a ratio of 90:10. The AUC value of each spectrum in various concentrations is calculated to selected wavelength range analysis. Then, this method was applied to determine the levels of INH and PDX in commercial tablets. Results:The application of AUC spectrophotometry UV method for determining the levels of INH and PDX was performed on wavelength range 262.2-272.2 nm and 289.8-299.8 nm, respectively. The selection of wavelengths based on wavelengths gives the best result. The mean % recoveries were found to be at 99.69% and 101.09% for INH and PDX, respectively. Conclusion:The method is successfully applied to analyze INH and PDX in pharmaceutical formulation simultaneously with no interference from excipients as indicated by all validation parameters which were within the acceptable range.