Ethyl chloroformate as a derivatizing reagent for the gas chromatographic determination of isoniazid and hydrazine in pharmaceutical preparations.

Ethyl chloroformate was examined as a precolumn derivatizing reagent for the gas chromatographic (GC) determination of isoniazid (INH) and hydrazine (HZ). Phenylhydrazine (PHZ) was used as an internal standard. GC separation was carried out on an HP-5 column (30 m x 0.32 mm i.d.) with flame ionization detection. The elution was carried out at an initial column temperature of 150 degrees C for 1 min at a heating rate of 10 degrees C/min up to 250 degrees C, nitrogen flow rate of 4 ml/min and a split ratio of 10:1, v/v. The linear calibration ranges for INH and HZ were observed between 3.5-37.5 and 3.5-35 microg/ml with corresponding detection limits of 0.18 and 0.17 ng reaching the detector. The method was subsequently applied to the determination of INH and HZ in pharmaceutical preparations, achieving a relative standard deviation (RSD) of 3.8-5.8%. The recovery percentage of INH from isoniazid syrup was 98% with an RSD of 5.2%.

Assessment of water quality of Manchar Lake in Sindh (Pakistan).

Manchar Lake is the largest natural freshwater lake in Pakistan. The Lake has received less fresh water in past few years. In addition, drainage water is being discharged in the Lake through Main Nara Valley Drain (MNVD) since many years. Consequently, concern has grown regarding the water quality of the Lake. The aim of this study was to assess the water quality of Manchar Lake and MNVD and the objectives were to determine physiochemical properties and the concentrations of common cations and anions as well as seven trace metals i.e. Cu, Ni, Zn, Co, Fe, Pb and Cd. The concentration of the trace metals were determined by simultaneous preconcentration and solvent extraction using flame atomic absorption spectrometer. Results of physicochemical parameters of Manchar Lake water samples showed mean pH 8.4 (+/-0.2), conductivity 2,310.3 (+/-581.3) muS cm(-1) and hardness (as CaCO3) 213.1 (+/-62.3) mg l(-1). Mean concentrations of cations and anions were Na 521.5 (+/-49.7), Cl(-) 413.6 (+/-225.7), Ca 70.7 (+/-12.9), Mg 56.2 (+/-28.9), K 17.6 (+/-6.5), NO(3-) 0.34 (+/-0.2) and PO4(3-) 0.02 (+/-0.01) mg l(-1). Mean concentrations of trace metals were Zn 15.7 (+/-1), Fe 12 (+/-3.5), Pb 9 (+/-2.7), Cu 8.9 (+/-7.7), Ni 4.3 (+/-3.4), Co 4 (+/-3.4) and Cd 1.1 (+/-1) microg l(-1). MNVD water samples showed mean pH 8.9 (+/-0.8), conductivity 1,735.7 (+/-567.8) muS cm(-1) and hardness (as CaCO3) 184.8 (+/-32.4) mg l(-1). In MNWD, the mean concentrations of cations and anions were Na 482.7 (+/-11.7), Cl(-) 395.7 (+/-271.5), Ca 79.1 (+/-23.5), Mg 54.2 (+/-28.1), K 26.2 (+/-21.3), NO(-3) 0.5 (+/-0.3) and PO4(3-) 0.1 (+/-0.1) mg l(-1). Mean concentrations of trace metals observed in MNWD water were Fe 14.9(+/-3.5), Cd 8.3 (+/-9.4), Pb 6.9 (+/-2.4), Cu 6.6 (+/-3.1), Zn 6.2 (+/-1.8), Co 4.5 (+/-2.7), and Ni 3.5 (+/-2.9) microg l(-1). The pH of both Manchar Lake and MNVD waters and concentration of Pb in Manchar Lake and concentration of Cd in MNVD water were higher than the World Health Organisation's guideline values for the drinking water quality. The water quality of Manchar Lake was found degraded.

High performance liquid chromatographic determination of platinum in blood and urine samples of cancer patients after administration of cisplatin drug using solvent extraction and N,N'-bis(salicylidene)-1,2-propanediamine as complexation reagent.

A high performance liquid chromatographic (HPLC) procedure has been developed for the determination of cisplatin, based on the pre-column derivation of platinum(II) with reagent N,N'-bis(salicylidene)-1,2-propanediamine (H2SA2pn). The neutral platinum complex was extracted, concentrated in an organic solvent and then injected (5 microl) on a reverse phase HPLC column, Varian Micro-Pak SP C-18, 5 microm (150 mm x 4.0 mm i.d.). The complex was eluted isocratically using a ternary mixture of methanol/acetonitrile/water (40/30/30, v/v/v) at a flow rate of 1.0 ml/min and was determined by a UV detector set at 254 nm after elution. A detection limit was found to be 4.0 ng per injection. The amounts of platinum in blood serum and urine of cancer patients after administration of cisplatin were observed in a range of 221-298 ng/ml and 43-97 ng/ml with relative standard deviation (R.S.D.) of 3.6-4.6% and 3.5-4.8%, respectively. Preliminary metabolism profiles of Pt concentrations in blood and urine from the patients were established.