Introduction: There are different ways for identification of Mycobacteria. One of the most sensitive method is HPLC of phenacyl esters of mycolic acids of Mycobacteria for rapid identification of them after their primary cultures. This study uses HPLC for rapid identification and dissociation of Mycobacterium tuberculosis complex. Methods: In this study we use HPLC patterns of mycolic acids for identification three important species of mycobacteria (M. tuberculosis, M. bovis, M. bovis BCG) from other mycobacterial species. All the strains were obtained from Tuberculosis and Pulmonary Diseases Research Center. HPLC conditions was as follows: HPLC: Model 1200 Cecil, Column: URP C-18 25X4.6 mm, Detector: U.V variable wave length at 254 nm, Elution: Gradient of methanol/chloroform. Flow rate: 2.5 ml/min.Results: HPLC leads to obtaining chromatograms which on its X-axis retention times (of different peaks which exist in the sample) and on its Y-axis U.V absorbance (of these peaks) were drown. These chromatograms in M. bovis and M. tuberculosis samples are similar with each other but differs from BCG ones.Discussion: On the basis of different retention times and numbers of the peaks which present in each chromatogram, we can differentiate between M. bovis, M. tuberculosis and BCG from other Mycobacteria. Also, with this method we can identify BCG from M. bovis and M. tuberculosis (because BCG has 9 and M. bovis and M. tuberculosis has 7 characteristic peaks in their chromatograms).

An accurate and sensitive reversed-phase HIGH-PERFORMANCE LIQUID chromatographic method for determination of sertraline in human serum is described using 4-chloro-7-nitrobenzofurazan as pre-column derivatization agent. The drug and an internal standard (azithrimycin) were extracted from serum using a mixture of diethyl ether-chloroform and subjected to the pre-column derivatization with the reagent. Analysis of the resulted derivatives was performed on a Lichrosorb CN (250×4.0 mm) column using a mobile phase composed of methanol and sodium phosphate buffer (0.05 M; pH 3.7) containing 2 ml/lit triethylamine (63:37 v/v). Detector response was monitored at excitation and emission wavelengths of 470 and 537 nm, respectively. The calibration curve was linear over the concentration range of 2 to 640 ng/ml. The lower limits of detection and quantification were 0.5 and 2 ng/ml, respectively. The validation of the analysis was carried out in terms of specificity, sensitivity, linearity, precision, accuracy and stability. The validated method was shown to be accurate, with intra-day and inter-day accuracy from 0.3 to 4.2% and precise, with intra-day and inter-day precision from 2.4 to 15.5%. The drug is detected at concentrations as low as 2 ng/ml in a 0.5 ml serum sample and the described method can be easily applied in human single-dose pharmacokinetic studies of sertraline.

This article describes a simple and fast HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY method for the determination of methotrexate (MTX) in plasma. Samples were collocted from children receiving HIGH-dose MTX at shafa Hospital (Ahvaz University of Medical sciences, Ahvaz, iran) at various times after the end of eachinfusion. Plasma was deproteinized with trichloroacetic acid and the supernatant was injected into a 250×4.6 mm octadecylsilane column. Mobile phase was made of TRIS-phosphate buffer (pH 5.7): methanol: acetonitrile (82:11:7) with a flow rate of 1.8 ml/min. Ultraviolet detection was done at 313 nm and at ambient temperature. Para-aminoacetophenone was used as internal standard. Methotrexate and internal standard retention times were 4.4 and 6.5 minutes, respectively. Results showed that reproducibility (precision) of method within a day was 2.6 to 6 percent and between days was 5.5 to 9.5 percent. The recovery of the method was between 61.5 and 72.7 percent. The quantitation limit of the method for methotrexate was 0.1 mM. This method is suitable for quantitation of methotrexate after infusion of HIGH doses of this drug and has good accuracy, precision and quantiatation limit.

Background and aims: Due to low concentration of melatonin and also the existence of other compounds in body fluids, measuring the amount of melatonin is a serious challenge for the analysts. Before measurement of melatonin amounts using chromatographic method, sample preparation is unavoidable. The aim of current study is develop a new sample preparation method that not only have HIGH accuracy and validity, but also can using by conventional equipment available in the laboratory to determine trace levels of salivary melatonin. For this purpose, the dispersive LIQUID-LIQUID micro extraction (DLLME) method, that has not been used so far to preparation of salivary melatonin samples, were optimized.Methods: Optimization procedure involved evaluation of eight factors affecting DLLME method. From these factors, seven were examined in four levels, and just pH was done in five levels. Accuracy and precision of the optimized method was evaluated at three concentrations of 50, 100, 250 pg.ml-1 by achieving CV% for day-to-day and within-day reproducibility.Results: Optimum values were determined. Accuracy and precision of the optimized method was investigated at three concentrations of 50, 100, and 250pg/ml by achieving CV% of 6.29, 2.39, and 1.82 for the "day-to-day" and 4.49, 2.68, and 1.83 for "within-day" reproducibility.Conclusion: Due to the results of this study for Coefficient of variations, the optimized method was provided with proper accuracy and precision. Although optimized extraction factors must be fit analyte, but these factors can be used for similar chemical compounds with a slight modification.

Background: The use of HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC) grade water is very important for laboratory studies, especially food quality control. These studies have a great impact on diagnosing food health. Food health improves the health of the community and these two parameters are closely related. HPLC grade water is ultra-pure water with low UV absorption ability. This water is often purified through a micron filter and all contaminants are removed. Methods: Thirty samples of HPLC grade water with Iranian and non-Iranian brands purchased from Tehran were tested for electrical conductivity and silica. Results: The quality of all the tested samples was approved which was lower than the allowable limit. None of the Iranian and non-Iranian samples exceeded the standard limit. Conclusion: This study indicated the good quality of this product. It was concluded that all the samples had desirable quality.

Enrofloxacin is an important antibiotic in poultry industry in Iran. Also, antibiotic residue is a serious health problem in this industry. This study was conducted to determine whether the doses of enrofloxacin would produce drug residue transfer into eggs when administer to laying hens. Forty hens were assigned to equal groups (n=10). 2, 5 and 10 mg/kg of enrofloxacin was injected to 1, 2 and 3 hens groups, respectively. All of groups were seven days under treatment. Then, eggs were collected at 1 to 7 days of treatment and 3, 6 and 9 days after last injection. Then, enrofloxacin residue was determined using HIGH PERFORMANCE LIQUID CHROMATOGRAPHY. The results of this study showed that increment of administered dose of enrofloxacin caused to increase drug residue in eggs. Furthermore, maximum drug residue was observed at seventh day of injections. In addition, drug residue was decreased to zero at ninth day after last injections. On the other hand, enrofloxacin residue concentration was detectable in group two hens at third day after last injections and in group three hens at third and sixth day after last injections. In conclusion, for minimum detection of enrofloxacin residue concentration in eggs must be increased the time between last injection of drug and eggs collecting.