毛细管气相色谱法测定合成革与人造革工业废气和废水中二甲基甲酰胺(DMF)

本文运用毛细管气相色谱法测定合成革与人造革工业中废气和废水中DMF,其废水、环境空气和废气中DMF的最低检测浓度分别为0.5 mg/L、0.167 mg/m3、0.333 mg/m3,该方法相对标准偏差为1.06%,加标回收率在95%-110%。实验表明该方法能为环境管理提供科学依据,完全满足了环境管理的要求。     

水产品中微囊藻毒素ELISA和LC/MS/MS检测

建立了水产品中微囊藻毒素ELISA和LC/MS/MS测定方法,样品经过提取、净化后,测定结果显示:ELISA最低检测限量为1.00μg/kg,1.00、5.00和10.0μg/kg 3个浓度添加水平,测定回收率范围为75.7%-98.7%,平均回收率为88.0%,RSD范围为5.52%-9.21%;LC/MS/MS最低检测限量为0.3μg/kg,5.00、15.0和20.0μg/kg 3个浓度添加水平,测定回收率范围为86.0%-109%,平均回收率99.1%,RSD范围0.65%-2.37%。两种方法20份实际样品测定结果显示:阴性样品和阳性样品符合率为100%,共有5份样品中含有MC-LR,当地监管部门应引起足够的重视,定时开展监测和信息公布。     

使用FIAstar 5000流动注射分析仪测定土壤中有效硅

本文使用流动注射分析仪测定了土壤样品中有效硅含量,工作曲线决定系数R2达0.9999以上,检出限为0.012μg/mL,相对标准偏差为0.04%-0.06%,样品加标回收率为97.89%-99.93%。实验证明该方法操作简便、线性好,其精密度、准确度、灵敏度都能符合分析工作要求。     

茶叶中啶虫脒残留量气相色谱分析方法研究

本文对茶叶中啶虫脒残留量的气相色谱分析方法进行了研究。方法:样品用乙腈提取后,采用活性碳固相萃取柱和弗罗里硅土固相萃取柱净化,采用电子捕获检测(ECD)的气相色谱仪测定。该方法检测底限为0.01 mg/kg,当样品添加浓度在0.05mg/kg-0.20mg/kg范围内,添加回收率在82.4%-100.7%,相对偏差为5.5%-7.7%。     

微量Nb对低合金钢组织转变的影响

研究了微量Nb对低碳钢FNS400连续冷却转变曲线和组织的影响。结果表明,微量Nb使钢的临界点Ac1、Ac3上升,Ms点下降,先共析铁素体转变开始线大幅度向右下移,发生贝氏体转变的最低临界冷速由3℃/s下降至0.8℃/s,发生马氏体转变的最低临界冷速由5℃/s下降到3℃/s,铁素体体积分数减少了1%-19%,珠光体增加了3%-11%,贝氏体增加了2%-18%,马氏体减少了2%-18%。     

热脱附-气相色谱法分析环境空气及废气中的苯系物

建立了热脱附-气相色谱法分析环境空气及废气中的苯系物的方法,并对实际气样进行了测定。各目标物的线性回归R值均大于0.999,MDL为0.23-0.33μg/m3,RSD为3.2%-5.2%,回收率为96.3%-99.8%。     

高效液相色谱-串联质谱法快速测定饮料中亮蓝

本文建立了一种高效液相色谱-串联质谱联用快速测定饮料中亮蓝的新方法。使用脱气、调节pH等简单的样品前处理后,利用HPLC-ESI(+)MS/MS对亮蓝二级特征离子m/z735进行定性定量检测,5min内即可完成,方法检出限为0.2μg/kg,加标样品回收率在92.0%-97.8%,相对标准偏差3.5%-5.7%。该方法简便、快速、灵敏度高,抗干扰能力强,适用于饮料中亮蓝的痕量检测。     

捕集阱顶空-气相色谱法测定地表水中三氯乙醛

本文利用水合三氯乙醛在碱性条件下生成三氯甲烷的性质,以捕集阱顶空-气相色谱法测定三氯甲烷从而间接测得三氯乙醛的浓度。同时对实验条件进行了优化,确定了实验用水为Mill-Q超纯水,氢氧化钠加入量为15mg,氯化钠加入量为1.0g,平衡温度为60℃,平衡时间为30min,捕集阱循环次数为3次。实验结果表明,此方法在0.200μg/L-20.0μg/L的浓度范围内线性关系良好,回收率为86.0%-105.0%,相对标准偏差为3.0%-4.6%,检出限为0.07μg/L,其中灵敏度较普通顶空进样法提高了近6倍。该方法具有较高的灵敏度、精密度和准确度,满足地表水中三氯乙醛的测定要求。     

气相色谱质谱法检测蔬菜中多效唑的残留

建立了白菜和黄瓜中多效唑残留的检测方法.样品经乙腈提取,弗罗里硅土固相萃取小柱净化,以气相色谱/质谱选择125,167,236三个碎片离子进行定性定量分析.结果表明,多效唑在0.050-1.0mg/L范围内呈线性关系(R为0.9998),3种不同添加浓度0.040mg/kg、0.10mg/kg和0.50mg/kg下白菜和黄瓜中多效唑的平均添加回收率在89.04%-99.77%之间,变异系数在2.57%-7.51%之间,检测限(S/N=3)为0.01 mg/kg,方法适用于蔬菜中多效唑的检测.     

高效液相色谱法测定纺织品中苯并三唑类光稳定剂

以乙酸乙酯为提取溶剂,使用超声波辅助萃取-高效液相色谱测定纺织品中2-（2＇-羟基-3＇,5＇-二叔丁基苯基）-苯并三唑,并对仪器的测试条件进行优化。该方法的平均回收率为93.1%-105%,相对标准偏差小于10%,方法检出限可低至0.1mg/kg。该方法操作简单快速,稳定可靠,适用于纺织品中2-（2＇-羟基-3＇,5＇-二叔丁基苯基）-苯并三唑的日常监测。     

Development and evaluation of a reference measurement procedure for the determination of total 3,3',5-triiodothyronine in human serum using isotope-dilution liquid chromatography-tandem mass spectrometry

3,3',5-Triiodothyronine (T3) is an important diagnostic marker for thyroid function. A reference measurement procedure (RMP) for total T3 in serum involving isotope dilution coupled with liquid chromatography-tandem mass spectrometry (LC/MS/MS) has been developed and critically evaluated. The method uses solid-phase extraction with mixed-mode retention mechanisms of reversed phase and ion exchange prior to reversed-phase LC/MS/MS. In addition to a labeled T3 internal standard (T3-13C9), labeled thyroxine (T4-d5) is also added to serum samples in order to monitor the degradation of T4 to T3. The accuracy of the measurement was evaluated by a recovery study for added T3 and was supported by a comparison study with the other RMP. The recovery of the added T3 ranged from 98.9% to 99.4%. The results of this method and the other RMP agreed to within 1%. Samples of frozen serum pools were prepared and measured in three separate sets. Excellent reproducibility was obtained with within-set coefficients of variation (CVs) ranging from 0.8% to 1.6% and between-set CVs ranging from 1.9% to 2.6%. Excellent linearity was also obtained with correlation coefficients of all linear regression lines (measured intensity ratios vs mass ratios) ranging from 0.9995 to 0.9996. The detection limit at a signal-to-noise ratio of approximately 3 was 1 pg of T3. The T4 degradation during sample preparation was minimized to a small percentage (no more than 3% of the T3 values) by use of antioxidants (ascorbic acid, dithiothreitol, citric acid) and can be accounted for in the T3 measurement process. This well-characterized LC/MS/MS method for total serum T3, which demonstrates good accuracy and precision, low susceptibility to interferences, accountability of the conversion of T4 to T3, and comparability with the other RMP, qualifies as a reference measurement procedure and can be used to provide an accuracy base to which routine methods for T3 can be compared.     

Absolute quantification of monoclonal antibodies in biofluids by liquid chromatography-tandem mass spectrometry

The development of a quantification method for monoclonal antibodies in serum has been accomplished by high-performance liquid chromatography multiple reactions monitoring mass spectrometry. A human monoclonal antibody (HmAb) was used as the model protein for method development and validation. A peptide from the CDR3-region of its heavy chain was selected and used for quantifying the entire mAb. This signature peptide served as a template for the internal standard. Prior to mass spectrometric analysis approximately 50% of the total serum protein content was removed by albumin depletion. The accuracy of the method ranged between 99 and 112% in cynomolgus monkey serum. The intra-assay coefficient of variation (CV) was lower than 4% at 4 microg/mL and 200 microg/mL HmAb (n = 3). The CV at 400 microg/mL corresponded to 9% (n = 3). In addition, the interassay variation was investigated in a male cynomolgus serum pool and in a female cynomolgus serum pool. The CV for the male cynomolgus pool at 4 microg/mL HmAb was 7% (n = 3). The CV obtained from the female pool was 8% (n = 3), at 4 microg/mL. The dynamic range of the method was 3 orders of magnitude. After albumin depletion of 25 microL of serum, a lowest limit of quantification of 2 microg/mL HmAb was reached in both human and cynomolgus monkey samples.     

Synthesis, structural and mechanical characterization of sputtered tungsten oxide coatings

Tungsten oxide coatings were deposited without substrate bias by DC reactive magnetron sputtering of a tungsten target using oxygen as reactive gas. By tuning the partial pressure of oxygen (p_O2/p_Ar) between 0 and 4, the oxygen content of the films was changed from 0 to 75 at.%. The structure of the films (investigated by X-ray diffraction) depends on their oxygen content. For low oxygen contents, the -W and β-W₃O phases were observed (< 30 at.%), and with the increase of oxygen content (30 at.% < O < 67 at.%) the structure became amorphous. A transition region was obtained for oxygen content between 67 at.% and 75 at.%, and when O > 75 at.%, a nanocrystalline (WO₃) structure was reached.

The hardness and Young's modulus were evaluated by depth sensing indentation. The decrease in hardness followed the four different ranges of chemical compositions accordingly, from ≈ 23 GPa for pure W down to ≈ 7 GPa for WO₃ films. A similar behaviour was observed for the Young's modulus, which ranged from 450 GPa to 150 GPa. The cohesion/adhesion of the films were investigated using a scratch-test apparatus. These coatings displayed a low adhesion (critical load, L_c < 15 N) to the steel substrate because the depositions were carried out intentionally without an adhesion interfacial layer.     

Determination of steroid hormones in oral contraceptives by high-performance liquid chromatography

The aim of this research was to standardize a high-performance liquid chromatographic method for quantitative determination of steroid hormones, like ethinylestradiol (ETE), levonorgestrel (LEVO), and gestodene (GEST), in commercially available oral contraceptives (OCs). The combination ETE- LEVO was analyzed using a LiChrospher® 100 RP-8 column (5 μm, 125×4 mm) in LiChroCART®, with a mobile phase constituted of acetonitrile: water (60:40 v/v). Using the same column, ETE-GEST was analyzed with a mobile phase constituted of acetonitrile:water (50:50 v/v) at pH 7.5 adjusted with 0.02 M ammonium hydroxide. For both methods, a flow rate of 0.8 mL/min was utilized and detection was carried out at 215 nm. All analyses were performed at room temperature (24±2°C).

Calibration curves for ETE-LEVO were obtained using solutions with concentration ranges from 2.40 to 60.0 μg/mL (ETE), and from 12.0 to 300.0 μg/mL (LEVO). Calibration curves for ETE-GEST were obtained using solutions with concentration ranges from 2.40 to 60.0 μg/mL (ETE), and from 9.0 to 160.0 μg/mL (GEST). Correlation coefficients obtained were from 0.9999 to 0.9990. Coefficients of variation for samples containing ETE-LEVO were 0.47% and 0.38%, respectively. For samples with ETE-GEST they were 0.39% and 0.44%, respectively. The average recovery for samples with ETE-LEVO was 103.46% and 100.78%, respectively. For samples containing ETE-GEST it was 100.89% and 101.03%, respectively.     

The effect of clove oil on the transdermal delivery of ibuprofen in the rabbit by in vitro and in vivo methods

The study was designed to evaluate skin permeation enhancement effect of essential oils from Eugenia caryophyllata (clove oil) in rabbits and to compare the in vitro absorption and in vivo permeation using ibuprofen as a model drug. The in vitro results indicated a significant permeation enhancement effect of the clove oil. The group with 1% oil appeared to the flux (239 μg/cm²/hr), and 3% oil was 293 μg/cm²/hr to some extent similar with 2% azone group (327 μg/cm²/hr). The enhancement ratio of clove oil was 7.3. In vivo results also demonstrated that clove oil showed a significant permeation enhancement effect, but the enhancement of clove oil was relatively weak than in vitro. The group with 3% oil exhibited the higher value of area under the curve (AUC) of 80.8 μg/mL·hr, which was 2.4 times the high of control. The AUC value of 3% oil group was similar to that of 2% azone group (89.8 μg/mL·hr). The GC-MS results indicated eugenol and acetyleugenol identified from clove oil might mainly contribute to enhance in vitro and in vivo absorption of ibuprofen because of its large quantities (90.93%).     

Infrared Transmission Curves of Pb0.1 Ca0.9La2S4 Pellets Densified by Pressureless Sintering

Highly sinterable submicron Pb_0.l Ca_0.9La₂S₄(PCLS) powders were prepared by sulfidizing calcium and lanthanum alkoxides al 500°C under CS, atmosphere for 8 hours and then in pure H₂S atmosphere at 600-800°C for 8 hours. After sintering the pellets were used as infrared transmitting window material of 8-14 μm wavelength. The CdS was added from 3 to 7 wt.% lo improve the sinterability by forming liquid phase during sintering. For sulfidization of lanthanum alkoxide, sulfide powder with LaS₂ phase was formed at 500°C, and a pure Th3P4 phase formed follow by 700°C heat treatment. A powder with β-La₂S₃phase formed at 800°C, and a pure Th₃ P₄phase formed follow by 900°C heat treatment. The powder with β-La₂S₃ phase was sintered to full density at 1350°C by adding 3 wt.% CdS. The PCLS powder with Th3P4 phase sintered to full density at 1400°C by also adding 3 wt.% CdS. The pellet exhibited 45% transmittanceat 13 μm when sintered from the powder with p-La₂S₃phase. The transmittance at 2.5 μm for the pellet sintered from the PCLS powder with Th₃P₄ type structure was 3 times higher than that from the p-La₂S₃ powder.     

Biological denitrification of drinking water in a slow sand filter

Biological removal of nitrate from drinking water was studied in a slow sand filter. Optimum carbon to nitrogen ratio (C/N) was found to be 1.8 when using acetic acid in batch tests. The filtration rates impact on NO(3)-N removal through the sand filter was assessed for 22.6 mgNO(3)-N/l concentrations while keeping C/N ratio as 1.8 for acetic acid. The filtration rates varied from 0.015, 0.02, 0.03, 0.04, 0.05, and 0.06 m/h, respectively, corresponding to an overall average NO(3)-N removal efficiency of 94%. Although increasing filtration rates decreased NO(3)-N removal, effluent NO(3)-N concentrations at the effluent port were lower than the limit value. The slow sand filter process was unable to provide NO(3)-N removal rate more than 27.1 gN/(m(2)day) (0.05 m/h flow rate). The NO(3)-N removal efficiency slightly dropped from 99% to 94% when the loading rate increased from 27.1 to 32.5 g/(m(2)day), but the effluent water contained higher concentration of NO(2)-N than the standard value.     

Thermoelectric properties of the n-type 85% Bi2 Te3-15% Bi2 Se3 alloys doped with Sbl3 and CuBr

The temperature dependence of the Hall mobility, Seebeck coefficient, electrical resistivity, thermal conductivity, and figure-of-merit of the SbI3 and CuBr-doped 85% Bi2Te3-15% Bi2Se3 single crystals have been characterized at temperatures ranging from 77 K to 600 K. The scattering parameter in 85% Bi2Te3-15% Bi2Se3 single crystal was determined as 0.1 from the temperature dependence of the carrier mobility. With increasing the amount of Sbl3 or CuBr doping, the Seebeck coefficient of 85% Bi2Te3-15% Bi2Se3 decreased and the temperature at which the Seebeck coefficient shows a maximum shifted to higher temperature. Compared to the Sbl3-doped specimens, the CuBr-doped single crystals exhibited higher (m* / m0)3/2 c, implying that CuBr is a more effective dopant to improve the material factor and thus the figure-of-merit of 85% Bi2Te3-15% Bi2Se3. The maximum figure-of-merit of 2.0 × 10–3/K and 2.2 × 10–3/K was obtained for 0.1 wt % Sbl3-doped specimen and 0.03 wt % CuBr-doped specimen, respectively.     

Development of a Transdermal Delivery Device for Melatonin In Vitro Study

The present study was undertaken to develop a transdermal delivery device for melatonin and to determine the effects of system design on the release of melatonin. Melatonin(MT) diffusion characteristics from 2 solvents through a series of ethylene vinyl acetate membranes with 4.5%, 9%, 19%, 28% vinyl acetate were characterized using vertical Franz® diffusion cells. The solvent used were 40% (v/v) propylene glycol (PG) and 40%(v/v) propylene glycol with 30%(w/v) 2-hydroxypropyl-β-cytrodextrin. The best release rate (Jss = 0.795 μg/h/cm²) was obtained from the 40% PG vehicle through the 28% vinyl acetate membrane. Melatonin diffusion through this membrane with an acrylate pressure sensitive adhesive (PSA) with and without MT loading was also studied. The data revealed an interaction between MT and the PSA in the systems with MT-loaded adhesive. A MT transdermal delivery device was constructed based on the above data. Effect of storage time (1 day, 2 days, and 3 days) on the developed device was also investigated. Steady state flux values of MT did not vary significantly with storage time (p-value = 0.14). The steady state flux was 1.88 ± 0.6 μg/hr/cm²(n = 9). However, storage time did affect the burst effect of MT. Total amount of MT released in the first hour was 137.4 ± 25.7 μg after 3 days, 61.5 ± 8.9 μg after 2 days, and 43.8 ± 20.9 μg after 1 day.     

Medicament Release from Ointment Bases: I. Indomethacin. In Vitro and in Vivo Release Studies

The in vitro release of indomethacin from 1%, 3%, and 5% indomethacin ointments and its in vivo absorption through the skin of rabbits was investigated. The in vitro release of indomethacin followed zero-order kinetics and was better from an absorption base ointment. No significant differences (F=3.047 and P=0.079 for the absorption base) and (F=2.15 and P=0.14 for the hydrophilic base) in the release rate of indomethacin in 1%, 3%, and 5% indomethacin ointments were observed. Indomethacin was most effectively absorbed from absorption ointment bases. A correlation between the in vitro release and the in vivo absorption was found; also, a correlation between the in vivo release pattern of the bases used and the in vivo data reported in the literature was observed.