[Spectrophotometric determination of trace amount of copper with trimethoxyphenylfluorone in microemulsion after preconcentration and separation by sulphydryl dextran gel].

In this paper, the color reaction of copper with trimethoxyphenylfluorone (TM-PF) in microemulsion has been studied. Copper (II) reacts with TM-PF to form a stable 1:2 complex at pH 10.40. Its apparent molar absorptivity is 1.46 x 10(5) L x mol(-1) x cm(-1) at 552 nm. Beer's law is obeyed in the range of 0-0.6 microg x mL(-1). Sulphydryl dextran gel (SDG), in which sulphydryl group has a big share, is a new type of metallic ion adsorbent. It presents the advantage of higher adsorption capacity, better reuse ability and higher mechanical stability. So the coexistent metal ions can be separated effectively and copper can be enriched by SDG, greatly improving the selectivity and sensibility of the system. The method was used to determine trace amount of copper in blood, urine, iron ore and water samples with satisfactory results, the relative standard deviation is less than 4.8%, and the recovery is 94.2%-106%.

[Spectrophotometric determination of trace amount of lead with trimethoxyphenylfluorone in microemulsion after using sulphydryl dextran gel for preconcentration and separation].

In this paper, the color reaction of lead with trimethoxyphenylfluorone (TM-PF) in microemulsion has been studied. Lead (II) reacts with TM-PF to form a stable 1:2 complex at pH 9.1. Its apparent molar absorptivity is 5.32 x 10(4) L x mol(-1) x cm(-1) at 565 nm. Beer's law is obeyed in the range of 0-1.5 microg x mL(-1). Sulphydryl dextran gel (SDG), in which sulphydryl group has a big share, is a new type of metallic ion adsorbent. It presents the advantage of higher adsorption capacity, better reuse ability and higher mechanical stability. So the coexistent metal ions can be separated effectively and lead can be enriched by SDG, greatly improving the selectivity and sensibility of the system. The method was used to determine trace amount of lead in blood, hair and urine samples with satisfactory results.

[Study on the synthesis of a new reagent 3-(4'-fluorophenyl)-5-(2'-arsenoxylphenylazo)-rhodanine and the fluoresence determination of bismuth(III)].

A new fluorescence reagent, 3-(4'-fluorophenyl)-5-(2'-arsenoxylphenylazo)-rhodanine, was synthesized. The structure of the reagent was clarified by elemental analysis and IR. At pH 5.4, the reagent can react with trace bismuth (III) to form a chelate which reduces the fluorescence intensity greatly. And when lambdaex/lambdaem = 305/407 nm, the fluorescence is intensive. There is a linear relationship between the decrease of fluorescence intensity and the concentration of bismuth (III) in the range of 0-0.025 microg x mL(-1). The detection limit is 1.2 x 10(-10) g x mL(-1). A new method of fluorescence spectrophotometric determination of bismuth (III) was developed.

Rapid determination of 5-fluorouracil in plasma using capillary electrophoresis.

A rapid, simple and sensitive capillary electrophoresis (CE) method used for the determination of 5-fluorouracil in rabbit plasma is described in the present paper. In this method, samples were simply pretreated by a solvent extraction procedure prior to injection. With a running buffer composed of 30 mM Tris-H(3)PO(4) (pH 7.0) and 5% isopropanol, 5-fluorouracil was easily separated from the external standard alpha-phenethylol as well as other substances existed in the plasma. A linearity of 5-fluorouracil was determined in the range from 0.17 to 42.50 microg/ml with a correlation coefficient of 0.999. A limit of quantitation (LOQ) corresponding to signal-to-noise ratio of 10 was obtained (LOQ=0.08 microg/ml). The method was successfully used for determining the 5-fluorouracil in real plasma samples from rabbits.

Separation and determination of phenylpropanoid glycosides from Pedicularis species by capillary electrophoresis.

Capillary zone electrophoresis, using 30 mM borate buffer (pH 9.00) with 10% (v/v) methanol, was established for the identification and determination of four phenylpropanoid glycosides (PPGs)--echinocoside (ECH), verbascoside (VER), pedicularioside M (PED-M) and pedicularioside A (PED-A)--in extracts of Pedicularis longiflora var tubiformis, Pedicularis longiflora and Pedicularis Kansuensis. Regression equations revealed linear relationships (correlation coefficients: 0.9993-0.9999) between the peak area of each compound (ECH, VER, PED-M and PED-A) and its concentration. The relative standard deviations of the migration times and peak areas were <1.93 and 4.54%, respectively. The recoveries of four PPGs ranged between 95.6 and 108.4%. The effects of several CE parameters on the resolutions were studied systematically.

[Determination of purity of different types of aprotinin by micellar electrokinetic capillary chromatography].

A sensitive and rapid method was developed for purity determination of different types of aprotinin by micellar electrokinetic capillary chromatography (MECC). MECC was performed with 80 mmol/L Na2HPO4-H3PO4(pH 7.00) buffer solution containing 4 mmol/L cetyltrimethyl ammonium bromide (CTAB) at an applied voltage of 15 kV. The electrophoresis was monitored at 277 nm, and completed in 6 minutes. The relative standard deviations of migration time and area for aprotinin were below 0.3% and below 5% respectively within 1 day (for 6 repetitive runs). The effect of high concentration of salt in the samples has been studied. The results obtained by capillary zone electrophoresis, MECC and high performance liquid chromatography were compared, and those of MECC were the best.