流动注射化学发光法测定甲氨蝶呤

研究了甲醛增强高锰酸钾与甲氨蝶呤的化学发光反应，由此建立了一种测定甲氨蝶呤的流动性注射化学发光分析法，方法的检出限为３．４×１０＾－９ｇ／ｍＬ，相对标准偏差为１．１％（２．０×１０＾－６ｇ／ｍＬ甲氨蝶呤，ｎ＝１１）线性范围为１．０×１０＾－８～１．０×１０＾－５ｇ／ｍＬ。该法已用于甲氨蝶呤针剂及片剂中甲氨蝶呤含量的测定。     

利用天然斜发沸石从高离子强度的强碱性溶液中吸附和洗脱K+和Rb+的研究

在80℃下，用间歇法研究了NH4^ 型天然斜发沸石对某厂高离子 强碱性循环液中的K^ 和Rb^ 的吸附，得到不同粒度天然斜发沸石对K^ 和Rb^ 的交换吸附量，用不同浓度的NH4HCO3溶液对沸石进行洗脱再生，是到洗脱速率随着洗脱液浓度增大而增大。本文对沸石与钾含量很高的高离子强度强碱性溶液中碱金属的交换吸附和洗脱过程进行了初步探讨。     

HPLC–MS Analysis of Isoniazid in Dog Plasma

A simple, rapid, and sensitive liquid chromatography–mass spectrometric (LC–MS) method was developed and validated for the determination of isoniazid in dog plasma. Plasma samples were deproteined with methanol and separated on a C₁₈ column interfaced with a single quadrupole mass spectrometer, using 0.1% formic acid–acetonitrile (91:9 v/v) as mobile phase. Detection was performed by positive electrospray ionization with selected ion monitoring at m/z 138 for isoniazid and 152 for entecavir maleate internal standard. Linearity was obtained over the range of 25–5,000 ng mL^?1, with a lower limit of quantification of 25 ng mL^?1. The intra- and inter-day precision was less than 2.7% in terms of relative standard deviation. Accuracy, expressed as relative error, ranged from ?2.0 to 8.0%. Plasma samples were analysed within 5 min. The method was successfully applied to the evaluation of the pharmacokinetics of isoniazid in dog plasma.     

Chemical modification of L-asparaginase with N, O-carboxymethyl chitosan and its effects on plasma half-life and other properties

E.coli L-asparaginase,an antitumor enzyme,was chemically modified with N,O-carboxymethyl chitosan to lower its artigenicity and increase its plasma half-life.The results showed that the modified L-asparaginase has almost the same apparent Km value as that of native enzyme.The modified L-asparaginase also showed a higher protease stability against trypsin and a-chymotrypsin.After being modified,the enzyme exhibited the complete loss of antigenicity towards antiasparaginase serum.In addition,the higher the molecular weight of modifying reagents,the better the effects on reduction of antigenicity.When tested in vivo,the plasma half-life of the modified enzyme (t1/2=40 h) was over 33 times longer than that of the native enzyme (t1/2=1.2 h).     

Viscosity effect on the structural compactness of latex flocs formed under weak depletion attractions

Dilute aqueous dispersions of colloidal polystyrene latex spheres were flocculated by adding a nonadsorbing polymer sample, poly(acrylic acid). The structural compactness of the flocs thus formed was characterized in terms of their mass fractal dimension using the small-angle static light scattering technique. It was found that with low poly(acrylic acid) concentrations and thus weak depletion attraction forces, the dispersion medium viscosity had a marked effect on the floc structure. An increase in the viscosity led to formation of denser flocs. This was revealed in three sets of depletion flocculation experiments: (a) adjusting the background electrolyte concentration at a fixed level of poly(acrylic acid), (b) using water and 30% (w/w) glycerol as the respective solvents, and (c) inducing latex flocculation with two poly(acrylic acids) of different molecular weights at the respective critical polyacid concentrations. Direct force measurements were made with atomic force microscopy to isolate the influence of viscosity on floc structure from that of interparticle interaction energies. We conclude that the formation of denser flocs with increasing medium viscosity can be attributed to the reduced diffusivity of particles in the solution. The latter resulted in an enhanced rate of floc restructuring (through relaxation of attached particles) relative to floc growth.     

弹性体型聚氨酯和聚碳酸酯共混物的形态结构

用ＤＳＣ、ＷＡＸＤ和ＳＡＸＳ研究了溶液共混的弹性体型聚氨酯（ＰＵ）／聚碳酸酯（ＰＣ）共混物的结构。结果表明，ＰＵ／ＰＣ为部分相容体系；共混过程中，溶剂ＤＭＦ的诱导作用使ＰＣ形成结晶，其长周期与ＰＵ硬段形成微相的长周期相近     

新型紫外衍生试剂用于D-氨基酸的毛细管电泳分离

采用一种新型紫外衍生试剂对乙酰氨基苯磺酰氟(PAABS-F)作为柱前衍生试剂,成功地对19种标准D-氨基酸和甘氨酸进行了衍生和毛细管电泳分离。详细研究了各种分离条件对毛细管电泳分离的影响。实验结果表明:采用20 mmol/L硼砂(pH 9.3),126 mmol/L十二烷基硫酸钠,8 mmol/Lβ-环糊精和20mmol/L NaC l时分离结果最佳,16 m in内实现了20种氨基酸的基线分离。     

冷态德士古气化炉流场与停留时间分布的研究

测定了德士古气化炉的冷态速度分布和停留时间分布。结果表明：德士古气化炉内在轴向２．５～３．０倍直径范围内存在回流，最大回流量为射流量的３．５倍左右；在平均停留时间之前，已有５０％左右的物料逸出炉外。本文指出，德士古气化炉中存在的问题，如结渣、耐火砖寿命短、有效气体成分偏低均与炉内流场有关。     

Photo-induced Charge Separation of p-Tricyanovinyl-N,N-Dialkylanilines

In this paper,p-tricyanovinyl-N,N-dialkylanilines were synthesized as model compounds and through their spectroscopic behavior,the photo-induced electron transfer,charge separation were discussed and the aggregation in DMSO-H_2O system was investigated.