离子色谱法测定电子烟烟液中氨的含量

建立了测定电子烟烟液中的氨含量离子色谱法。样品经10 mol·L-1盐酸溶液萃取10 min后,采用Dionex Ion Pac CS16A阳离子交换柱分离,以MSA为淋洗液进梯度洗脱,用电化学检测器检测。氨的质量浓度在0.05~1.0 mg·L-1范围内与峰面积呈线性关系,检出限(3S/N)为0.035μg·g-1,测定下限(10S/N)为0.12μg·g-1。方法用于12种市售品牌电子烟烟液中氨的测定,加标回收率在93.2%~106%之间,测定值的相对标准偏差(n=5)小于4%。     

流动注射-分光光度法测定钴钼催化剂浸渍液中高浓度钼离子

在0.75mol·L-1硫酸溶液中,抗坏血酸可将Mo6+还原为Mo5+,而硫氰酸铵能与生成的Mo5+显色,在波长465nm处有最大吸收峰,据此提出了一种流动注射-分光光度法测定钴钼催化剂浸渍液中超高浓度钼离子含量的方法。钼的质量浓度在3.3～93.3g·L-1范围内与其ΔA呈线性关系,方法的检出限(3s/k)为0.35g·L-1。方法用于钴钼催化剂浸渍液中钼离子含量的测定,测得方法的回收率在95.0%～101%之间,测定值的相对标准偏差(n=11)小于1%。     

基于磷钼蓝反应测定钴-钼催化剂浸渍液中钼离子含量

基于磷钼蓝反应测定钴-钼催化剂浸渍液中钼离子含量。建立了一个流动注射-磷钼蓝分光光度法测定高浓度钼离子的含量,优化后的条件为:1酸度调节剂为0.5mol·L-1硫酸溶液;2载流为超纯水;3反应试剂为120g·L-1磷酸二氢钾、100g·L-1抗坏血酸及0.3mol·L-1硫酸的混合液;4总流量为2.8 mL·min-1;5酸度调节盘管长度为20cm;6反应盘管长度为250cm。三氧化钼的质量浓度在10.0~300.0g·L-1范围内与峰高呈线性关系,检出限(3s/k)为2.0g·L-1。方法用于钴-钼催化剂钼浸渍液的分析,回收率在99.7%~105%之间,测定值的相对标准偏差(n=11)小于1%。     

铬黑T流动注射法在线测定水样中的微量Ni(Ⅱ)

利用铬黑T(EBT)与镍(Ⅱ)发生显色反应,生成一种紫罗兰色的配合物,建立了新的在线分析镍的流动注射法。在pH为10的H2B4O7-KCl-NaOH缓冲溶液中,铬黑T用量2.5 mL,缓冲液用量2.5 mL,灵敏度最好。方法的线性范围为10～1000μg·L-1,在10～100μg·L-1浓度范围内,ΔA=0.4234C+3.4336,R2=0.9998;在100～1000μg·L-1浓度范围内,ΔA=0.3907C+12.869,R2=0.9985,线性关系良好。检出限(3S/N)为3.4μg·L-1,加标回收率在98.8%～104.2%之间,相对标准偏差(n=14)为1.82%(200μg·L-1的镍标液),结果令人满意。     

离子色谱法测定脱硫石膏粉中硫酸钙含量

用离子色谱法测定了脱硫石膏粉中硫酸根的含量,并以此换算成硫酸钙的质量分数。样品(0.050 0g)溶于盐酸(1+1)溶液0.5mL中,于容量瓶中定容为100mL,静置24h后定量移取部分上清液稀释25倍。分取20μL进样作离子色谱分析。样液经过Metrosep A SUPP1柱净化,流出液通过Metrosep A SUPP5阴离子交换柱,以含1.8 mmol·L-1碳酸钠溶液和1.7mmol·L-1碳酸氢钠溶液的混合溶液为流动相进行淋洗,采用抑制电导检测。以实际样品为基体在2个浓度水平上加入硫酸根标准溶液进行回收试验,测得回收率大于95%。对同一样品作8次测定,测定值的相对标准偏差小于1%。     

高效液相色谱-串联质谱联用测定鳗鱼中孔雀石绿、结晶紫及其代谢物残留量

应用高效液相色谱与串联质谱联用技术测定了鳗鱼中孔雀石绿(MG)、结晶紫(CV)及其代谢物(LMG,LCV)的残留量.样品用乙腈提取后,经脱脂、浓缩及净化处理,所得残渣用流动相混合液溶解后,通过Acquity UPLCTM BEH C18色谱柱分离,流出液供串联质谱测定,用氘代孔雀石绿及氘代无色孔雀石绿作内标参比定量.结果表明:对MG、LMG、CV、LCV四种化合物在0.1～10.0 μg·L-1范围内均呈线性关系,在0.5 μg·kg-1及2 μg·kg-1的标准加入水平下进行了回收试验,所得回收率在86.5%～91.8%之间,方法的检出限为0.1 μg·L-1(对MG及LMG)和0.5 μg·L-1(对CV及LCV),测定结果的相对标准偏差(n=7)≤7%.     

电感耦合等离子体质谱法测定水体中溴和碘量

采用电感耦合等离子体质谱法测定水体中溴和碘的含量。水样无需前处理与内标溶液稀释后直接测定,用氨水(1+99)溶液作介质和清洗液。以铟为内标物。溴和碘的质量浓度在100μg·L-1以内与其响应强度呈线性关系,溴的检出限为0.19μg·L-1,碘的检出限为0.083μg·L-1。对5μg·L-1溴和碘的混合标准溶液连续测定18次,测定值的相对标准偏差为2.3%(溴),1.9%(碘)。方法用于水样的分析,加标回收率在88.0%~110%之间。     

食品包装用塑料袋中残留苯系物的快速检测

利用顶空技术,采用质谱法测定,建立了一种快速测定食品包装用塑料袋中残留苯系物的质谱分析方法.苯同系物的基峰峰高与其浓度在以下范围呈线性关系0.29～29.36 μg·L-1(苯),0.29～28.87 μg·L-1(甲苯),0.29～28.67 μg·L-1(二甲苯);检出限依次为0.017,0.004,0.009 μg·L-1.回收率为91.0%～103.6%,相对标准偏差小于3.5%.     

高效液相色谱法同时测定发酵液中赤藓糖醇和L-赤藓酮糖的含量

建立了采用高效液相色谱(HPLC)同时测定发酵液中底物赤藓糖醇和产物L-赤藓酮糖含量的方法。采用Lichrospher 5-NH2色谱柱(250 mm×4.6 mm),柱温30 ℃,以乙腈-水(体积比为9:1)为流动相,流速1.0 mL/min。用示差折光检测器检测赤藓糖醇,检测器温度为35 ℃。用紫外检测器在室温下检测L-赤藓酮糖,检测波长为277 nm。所得赤藓糖醇的线性范围为1.00～100.00 g/L,相关系数为0.9985,检出限为0.10 g/L,定量限为0.45 g/L;所得L-赤藓酮糖的线性范围为1.00～100.00 g/L,相关系数为0.9958,检出限为0.50 g/L,定量限为0.87 g/L;赤藓糖醇的日内和日间相对标准偏差(RSD)分别小于3.28%和5.30%, L-赤藓酮糖的日内和日间RSD分别小于2.16%和2.25%;回收率均大于99%。取不同时间的发酵液样品分别用上述方法测定,结果表明所建立的HPLC法不受发酵液中其他组分的影响,可同时测定底物赤藓糖醇和产物L-赤藓酮糖的含量。     

硫氰酸盐双波长分光光度法测定高铅矿石中钼量

在常规的硫氰酸盐光度法测定钼的硫酸介质中,加入80g·L-1乙二胺四乙酸二钠盐(EDTA-2Na)溶液7mL,使48mg·L-1以下共存的铅(Ⅱ)无法生成硫酸铅,不干扰钼的测定,应用此条件测定了含铅量较高的矿石中钼的含量。样品(0.100 0~0.500 0g)于高铝坩埚中,用过氧化钠3g融熔,熔块用水浸出,定容至100mL,分取部分试液,加入EDTA-2Na溶液7mL后按常规条件显色,用双波长方法以460nm(λ1)为测定波长,650nm(λ2)为参比波长测量吸光度(A),计算ΔA(Aλ1-Aλ2)。钼的质量浓度在6.0mg·L-1以内与相应的ΔA之间呈线性关系,方法的检出限(3s/k)为8.1×10-3 mg·L-1。应用此方法测定了2个CRM(GBW 07238,GBW 07285)中的钼量,测定值与认定值相符,测定值的相对标准偏差(n=9)依次为2.8%,1.2%。     

气相色谱-质谱法测定哈茨木霉菌代谢产物中单端孢霉烯化合物的含量

利用气相色谱-质谱法建立了哈茨木霉菌发酵代谢产物中活性有效成分单端孢霉烯化合物含量的分析测定方法。用乙酸乙酯提取样品,并测定提取液中单端孢霉烯化合物的含量,以保留时间和单端孢霉烯化合物的质谱特征离子峰(m/z292、277、149、135、121和107)为定性分析依据,用外标法定量。在所建立的分析条件下,单端孢霉烯化合物的保留时间为8.09min,方法检出限为0.04μg/L;在0.5~50μg/L范围内具有良好的线性关系,相关系数为0.9998;回收率102.3%;RSD为0.86%。方法灵敏度高,选择性好,准确度高,可为哈茨木霉菌菌株改造和发酵生产研究中单端孢霉烯化合物的跟踪检测提供灵敏、准确的分析手段。     

Black Liquor Decolorization by Selected White-Rot Fungi

Five different strains of white-rot fungi have been tested for their ability to decolorize black liquor on plates and on solid-state fermentation using vermiculite as the solid inert support. Since the high salt concentration inhibited the growth of all fungi, the black liquor was dialyzed against distilled water prior to use. A preliminary step on plates was carried out to qualitatively determine the capacity of the fungal strains for black liquor decolorization. Out of the five fungi studied, Phanerochaete sordida, Pycnoporus sanguineus, and Trametes elegans exhibited the more conspicuous decolorization halos in malt extract medium, while the decolorization by all the strains was not evident when a defined culture medium was used. Cultures on solid-state fermentation using vermiculite as solid support were also tested, the liquid phase was malt extract or glucose-based medium and supplemented with different black liquor concentrations. Decolorization of black liquor was largely affected by the fungal strain, the concentration of black liquor, and the carbon source. The percentage of color removal ranged from 6.14% to 91.86% depending on the fungal strain and culture conditions. Maximal decolorization was observed in malt extract cultures after 60 cultivation days. Interestingly, decolorization in malt extract medium increased with increasing black liquor concentration. The highest decolorization value was achieved by Steccherinum sp. which reduced up to 91.86% the color of the black liquor in malt extract medium; this percentage is equivalent to 5.2 g L⁻¹ of decolorized black liquor, the highest value reported to date. Traditional technologies used for the treatment of black liquor are not always effective and may not to be an environmentally friendly process. Vermiculite–white-rot fungi systems are presented in this work as a promising efficient alternative for the treatment of black liquor.     

Studies of Cephalosporin C Purification by Ultrafitration

Cephalosporin C was produced with fermentation technique. There are many impurities (mycelium, protein et al) in its fermentation liquor, which can be removed by ultrafitration membrane separation. The ultrafiltration technique has been used for purifying the fermentation liquid of antibiotics^[1-2],however, its application in extraction of Cephalosporin C from its fermentation liquor has not been reported. In this paper, we use Ultra-flo ultraflitration membrane system (concludes UF-54 pilot plant, flat board membrane module, thin composite membrane of 30 thousand reject molecular weight) to purify #1-#3 fermentation liquors of Cephalosporin C, which were not pretreated except acidification(pH=3).     

Bacitracin production by a new strain ofBacillus subtilis

A new strain ofBacillus subtilis C 126 was isolated from sugar cane fermentation and produced an antibiotic that inhibited the growth ofMicrococcus flavus. The production of the antibiotic in culture medium followed to extraction withn-butanol, thin layer chromatography, and microbiological tests indicated that a polypeptide antibiotic was produced. The fraction obtained by Sephadex G-25 column and analyzed by HPLC indicated that bacitracin complex was produced.     

快速简便的青霉素效价测定法——Ⅱ.场效应管型青霉素传感器的测定方法和应用

将已研制的场效应管(FET)型青霉素传感器应用于工厂和研究所发酵样液的青霉素效价测定。通过与现行的碘量法和比色法进行对比,证明FET型青霉素传感器能够代替碘量法与比色法,是一个简单、快速的青霉素效价检测法。     

Optimization of Inexpensive Agricultural By-Products as Raw Materials for Bacitracin Production in <Emphasis Type="Italic">Bacillus licheniformis</Emphasis> DW2

Bacitracin is a broad-spectrum antibiotic used extensively as a feed additive. In this study, inexpensive agricultural by-products were used as nitrogen sources for bacitracin production. Based on both the orthogonal tests, a combination of 7% soybean meal (SBM) +2% low protein rapeseed cake (LPRC) was optimal for bacitracin production. Compared to the original formula, the titer of bacitracin increased by 20.5% reaching 910.4 U/ml in flasks. The titer of bacitracin and the ratio of bacitracin A increased by 12.4 and 6.8% in a 50-l fermentor. Furthermore, this study also explored the effects of exogenously adding different amino acids on the yield of bacitracin. The addition of Cys and Glu enhanced bacitracin production by 5.7 and 5.0%, respectively. This study provided the inexpensive nutrient inputs into efficient bacitracin production and also the insight to further research enabling better utilization of oil cakes for economic viability of the bioprocess industry.     

Ethanol fermentation in a tower fermenter using self-aggregatingSaccharomyces uvarum

A self-aggregating strain ofSaccharomyces uvarum (U4) was used as a biocatalyst to carry out continuous ethanol fermentation in a tower fermentor equipped with a cell separator. Cell aggregates (2–3 mm) formed a stable packed bed in the fermentor, and the cell separator retained yeast cells effectively. Corn steep liquor was used as a nitrogen source for the fermentation of corn syrup and black strap molasses. An ethanol productivity of 54 g/L/h was reached using corn syrup at a dilution rate of 0.7/h, and sugar concentration in the feed was 15% (w/v). For molasses fermentation, an ethanol productivity of 22 g/L/h was obtained at a dilution rate of 0.7/h, and sugar concentration in the feed was 12.5% (w/v). Ethanol yields obtained from tower fermentation are higher than those obtained from flask fermentation (96% for corn syrup fermentation and 92% for molasses fermentation). No significant loss in fermentation activity was observed after 3 mo of operation.     

Xylanase and β-Xylosidase Production by <Emphasis Type="BoldItalic">Aspergillus ochraceus</Emphasis>: New Perspectives for the Application of Wheat Straw Autohydrolysis Liquor

The xylanase biosynthesis is induced by its substrate—xylan. The high xylan content in some wastes such as wheat residues (wheat bran and wheat straw) makes them accessible and cheap sources of inducers to be mainly applied in great volumes of fermentation, such as those of industrial bioreactors. Thus, in this work, the main proposal was incorporated in the nutrient medium wheat straw particles decomposed to soluble compounds (liquor) through treatment of lignocellulosic materials in autohydrolysis process, as a strategy to increase and undervalue xylanase production by Aspergillus ochraceus. The wheat straw autohydrolysis liquor produced in several conditions was used as a sole carbon source or with wheat bran. The best conditions for xylanase and β-xylosidase production were observed when A. ochraceus was cultivated with 1% wheat bran added of 10% wheat straw liquor (produced after 15 min of hydrothermal treatment) as carbon source. This substrate was more favorable when compared with xylan, wheat bran, and wheat straw autohydrolysis liquor used separately. The application of this substrate mixture in a stirred tank bioreactor indicated the possibility of scaling up the process to commercial production.     

赖氨酸的毛细管电泳特性及测定

研究了缓冲液pH和操作温度对赖氨酸毛细管区带电泳分离中运行电流、电渗迁移率、峰形等参数的影响,确定了赖氨酸电泳分离的最佳实验条件,建立了毛细管区带电泳测定赖氨酸的方法。线性范围为0．1－3．0g/L,检出限为0．03g/L。该法操作简便迅速,重复性好。用于赖氨酸发酵液中赖氨酸的含量测定,结果令人满意。     

气相色谱-质谱对青霉素发酵中玉米浆潜在标志物的研究

基于气相色谱-质谱(GC-MS)结合正交偏最小二乘判别分析法(OPLS-DA),建立了筛选玉米浆中影响青霉素发酵效价的潜在标志物的方法.利用GC-MS获得玉米浆中44种物质,经过标准化、Pareto预处理后,通过OPLS-DA对样本进行模式识别,根据模型的载荷图和变量重要性因子(VIP)筛选出9个潜在的标志物,即亮氨酸、5-酮脯氨酸、天冬氨酸、柠檬酸、酪氨酸、丝氨酸、赖氨酸、苏氨酸和葡萄糖.结果表明,这些物质与青霉素的初级代谢和次级代谢密切相关,可以作为筛选青霉素发酵优质原料的潜在质量指标.