木瓜蛋白酶水解法测定高梁中色氨酸含量

木瓜蛋白酶水解法测定高梁中色氨酸含量赵长峰，梅行，林希蕴，于豪捷，于红霞，朱萍用酸水解食物蛋白质能破坏其中的色氨酸。测定高梁中色氨酸含量，可用木瓜蛋白酶水解法。其原理是以氰离子激活的木瓜蛋白酶水解样品蛋白质，游离出的色氨酸吲哚基与显色剂形成紫红色化合...     

被污染包装纸中溴氰菊酯定量测定 吡啶—联苯胺比色法

<正> 本文将带有浪氰菊酯包装纸,用乙醇溶解过滤,加氢氧化钠使氰离子从溴氰菊酯中游离出来,再用吡啶联苯胺比色定量。本方法灵敏度高,使用仪器容易掌握,回收率均达90％以上,变异系数在5％左右。原理样品用乙醇溶解,过滤用氢氧化钠将氰离子从溴氰菊酯中游离出来,在酸性条件下,加溴水使之转变为溴化氰,用硫酸肼除去多余的溴,加入吡啶联苯胺试剂,生成桔红色戊烯醛衍生物,进行比色定量,本方法最低检出量为1.5μg溴氰菊酯。     

水浸提分离—离子色谱法测定PM_(2.5)中铵的含量

目的:建立测定PM_(2.5)的石英滤膜样品中铵离子水浸提分离—离子色谱方法。方法:将石英滤膜采集获得的环境空气细颗粒物PM_(2.5)样品进行水浸提分离后,在优化后的ICS-3000离子色谱仪上用标准曲线法定量加标准样品比对,对其中铵离子的含量进行测定。结果:铵离子标准曲线线性良好,相关系数r0.9994,方法检出限为0.13 mg/L,折算成膜上质量为0.046 mg/g;对配制的标准溶液连续重复测定6次,测定结果的相对标准偏差为2.79%;在待测样品滤膜中加入低、中、高三种不同浓度的标准溶液,铵离子加标回收率范围在84.5%～87.2%;比对标准样品中的铵离子,结果均在允许范围之内。结论:方法检出限低、精密度和准确度较好,结果令人满意,是一种适用于PM_(2.5)中铵离子的检测方法。     

湿法消解-高氯酸氧化-二苯氨基脲分光光度法测定冷饮中铬

目的：建立一种新的测定冷饮中铬的预处理、检测方法。方法：样品在消解赶酸后，加一定量的高氯酸，于190℃～210℃下使消解液中的铬氧化为六价，冷却后，不除去剩余少量的高氯酸，用EDTA溶液掩蔽干扰离子，利用：二苯氨基脲与六价铬生成红色化合物比色测定冷饮中的铬。结果：六价铬浓度在0—0．20mg／L范围内与吸光度呈良好直线关系，r=0.9995，检出限0．004mg／L。高、中、低含量样品测定的相对偏差2．6％～5．8％，回收率95．0％，98．1％。相对偏差≤5％时，常见离子不干扰测定。结论：该方法简便，准确，适合冷饮中铬的测定。     

工作场所空气中亚硝酸盐测定方法的对比研究

目的 对顶空气相色谱法和离子色谱法测定空气中亚硝酸盐进行对比研究.方法 分别采用顶空气相色谱法和离子色谱法对方法的灵敏度、准确度、精密度进行综合对比研究;同时将样品分为两组,根据2种方法的要求分别进行测定,将测定结果进行比较.结果 顶空气相色谱法的测定范围为0.56～20.0 μg/ml,检出限为0.56 μg/ml,相对标准偏差为0.77％～2.27％,加标回收率为95.2％～99.1％;离子色谱法的测定范围为0.50～30.0 μg/ml,检出限为0.50 μg/ml,相对标准偏差为0.38％～1.03％,加标回收率为97.0％～ 101.0％.2种方法测定空气中亚硝酸盐标准物质结果均在标示值范围内,2种方法对一组样品进行配对测试,结果经t检验分析,差异无统计学意义.结论 顶空气相色谱法和离子色谱法分析性能基本一致,均满足空气中亚硝酸盐含量的分析,适合批量样品分析.样品前处理简单省时,测定速度快,灵敏度高,干扰少.     

依莱铬氰分光光度法测定自来水中的铝

铝是比较常见的一种元素 ,近年来 ,研究人员发现 ,铝对人体健康有着重要的影响[1] 。国家生活饮用水卫生标准规定饮用水中铝最大含量不得超过 0 .2mg/L。目前 ,我国处理水的过程中 ,大都采用聚合氯化铝作为絮凝剂 ,不可避免的会在水中残留一定量的铝。因此对于准确测定自来水中铝的浓度 ,为预防因饮水而导致铝摄入量过多而对人体健康造成的损害 ,具有重要的疾病预防作用。用分光光度法测定水中铝的报道有很多[2 ] ,但用依莱铬氰做显色剂的报道还未见发表。本文用依莱铬氰做显色剂用于自来水中的铝的测定 ,结果表明 ,该方法简单、线性良好、…     

固相萃取-离子色谱法测定土壤中游离态的K+、Na+、Ca2+、Mg2+

目的：建立用固相萃取-离子色谱法测定土壤中游离态的K^＋ Na^＋ Ca^2＋ Mg^2＋ 含量。方法：采用固相萃取柱将土壤样品中干扰物质分离,用离子色谱法测定其中的K^＋ Na^＋ Ca^2＋ Mg^2＋ 的含量。结果：当样品中游离态K^＋ Na^＋ Ca^2＋ Mg^2＋ 的含量在0-10 mg/L时,其含量与峰面积呈线性关系,相关系数为0.9998-0.9999;样品的加标平均回收率在83.4%-96.0%之间。结论：该法操作简单、快速、灵敏度高、重现性好,用固相萃取技术大大降低了对色谱柱的污染,适于土壤中游离态的K^＋ Na^＋ Ca^2＋ Mg^2＋ 含量的测定。     

分光光度法测定食品中过氧化氢

目的：建立一种测定食品中过氧化氢的方法。方法：利用在酸性条件下过氧化氢与钛离子生成稳定的橙色络合物，用分光光度法测定其含量。结果：过氧化氢含量在25．0～500μg范围内，采用410nm波长、5.0ml钛显色剂、比色时间在30～60min内，该方法的相关系数r在0．9993以上，平均加标回收率98％。结论：该方法简单易行，准确可靠，可作为食品中过氧化氢的测定方法。     

气相色谱-质谱法同时测定鲜猪肉中氟乙酰胺和毒鼠强

目的 建立同时快速测定鲜猪肉中氟乙酰胺与毒鼠强的气相色谱-质谱法(GC-MS).方法 样品经乙腈提取,用增强型基质去除净化管Emr-Lipid净化,氮吹后乙酸乙酯复溶,经VF-624ms(30 m×0.25 mm×1.4 μm)色谱柱程序升温分离,采集模式选择离子模式(SIM),外标法定量.结果 氟乙酰胺与毒鼠强在0.1～2.0 mg/L范围内线性关系良好(r＞0.997);方法 检出限分别为0.08 mg/kg和0.09 mg/kg;氟乙酰胺的加标回收率为67.9％～75.4％,毒鼠强加标回收率为94.8％～104.0％.结论 建立的方法样本处理简单,检测快速准确,能够满足突发中毒事件快速反应的要求.     

气相色谱-质谱法同时测定鲜猪肉中氟乙酰胺和毒鼠强

目的 建立同时快速测定鲜猪肉中氟乙酰胺与毒鼠强的气相色谱-质谱法(GC-MS).方法 样品经乙腈提取,用增强型基质去除净化管Emr-Lipid净化,氮吹后乙酸乙酯复溶,经VF-624ms(30 m×0.25 mm×1.4 μm)色谱柱程序升温分离,采集模式选择离子模式(SIM),外标法定量.结果 氟乙酰胺与毒鼠强在0.1～2.0 mg/L范围内线性关系良好(r＞0.997);方法 检出限分别为0.08 mg/kg和0.09 mg/kg;氟乙酰胺的加标回收率为67.9％～75.4％,毒鼠强加标回收率为94.8％～104.0％.结论 建立的方法样本处理简单,检测快速准确,能够满足突发中毒事件快速反应的要求.     

核桃仁和西瓜子仁中磷脂成分的分析

采用红外光谱法分别对核桃仁和西瓜子仁中总磷脂进行含量分析,方法回收率为97.2％,精密度实验CV为1.66％,总磷脂含量核桃仁为438.46～528.85mg％,西瓜子仁为241.78～247.47mg％;以薄层色谱扫描和吸光度比例系数校正法分别测定了各样品磷脂组成及相对含量,结果表明,核桃仁和西瓜子仁均以磷脂酰胆碱(PC)和磷脂酰乙醇胺(PE)为主要磷脂组分;采用气相色谱-质谱-计算机联用法分析了总磷脂中脂肪酸的组成及分布。     

工作场所空气中甲酸、乙酸离子色谱检测方法的研究

目的建立工作场所空气中有毒物质(甲酸、乙酸)离子色谱检测方法。方法采用硅胶管采集工作场所空气中甲酸、乙酸,碳酸盐淋洗液1.0 mM Na2CO3/0.1 mM NaHCO3解吸,用AS23色谱柱进行分离,电导检测器检测,以保留时间定性,峰面积定量。结果乙酸、甲酸分离良好,检出限分别是0.3、0.03 mg/L;定量限分别为0.91 mg/L和0.12mg/L;回收率分别为96.5%~104%、95.3%~104%;工作曲线的线性范围分别为0.91~100、0.12~200 mg/L。样品中F-、Cl-、NO3-、PO4-、SO4-等常见阴离子对甲酸、乙酸的分离无干扰。结论该方法一次采样,同时检测甲酸、乙酸,具有操作简便、分离效果好、灵敏度高等优点。适用于工作场所空气中甲酸、乙酸的检测。     

High performance liquid chromatography for the quantitative determination of urinary phenylsulfate and phenylglucuronide as indices of benzene and phenol exposure in rats

Summary A high performance liquid chromatographic method for the determination of phenylsulfate and phenylglucuronide, metabolites of benzene, or phenol in urine is described. For the determination of urinary phenylsulfate, a stainless-steel column packed with octadecyl-silanized silica gel was used, and the mobile phase was mixed with a solution of methanol/water acetic acid (20/80/0.2) containing 0.05 M tetra-n-butylammonium bromide. For the exact determination of urinary phenylglucuronide, a stainless-steel column packed with the same resin was used and the mobile phase was a solution of methanol/water/acetic acid (50/50/0.2) containing 0.05 M tetra-n-butylammonium bromide. The method is simple and specific. Urine can be analyzed directly, without solvent extraction or pretreatment. The method has a lowest detection limit of 0.2 g on the column. The whole analysis and quantitative determination can be performed within about 15 min for samples containing phenylsulfate and phenylglucuronide in the urine of rats.The phenylsulfate excreted was equivalent to 36.1% and phenylglucuronide was 51.8% of phenol administered to rats intraperitoneally.     

Comparison of colorimetric methods for determination of phytic acid content in raw and oil extracted flour samples of maize

There are different colorimetric methods, with various analysis principles and phases, for the estimation of phytic acid content in agricultural products. Maize genotypes may possess a wide range of oil content, which is considered as a factor affecting the results of phytic acid analyses. Elaborative studies are needed to examine these methods to clarify the effect of oil content on the results, especially in the sample sets with varying oil concentrations. We utilized 4 different colorimetric methods; namely, AOAC, Wade, Chen and Haug-Lantzsch (H-L), to estimate phytic acid content in 19 maize genotypes, classified as having high (>7 %, n = 7) normal (3–5 %, n = 6) and low (<3 %, n = 6) oil content. Phytic acid determination was carried out on 2 groups of flour samples (raw: E1, and oil extracted: E2) using 3 replications. The results indicated that analysis methods yielded rather different phytic acid values. They also differed significantly in time and cost, with the Chen method being the cheapest and Haug-Lantzsch (H-L) the quickest. Oil extraction had significant effects on phytic acid results, and these effects varied across the analysis methods and the oil content of the genotypes. Our data suggest that either novel or improved colorimetric methods are necessary when analyzing phytic acid in special maize genotypes, considering the dissimilarity of the results from the current methods.     

离子色谱法测定血清中5-羟基吲哚乙酸含量研究

目的:建立简便快速梯度淋洗离子色谱法测定血清中5-羟基吲哚乙酸(5-HIAA)含量。方法:选用IonPac AS11阴离子分析柱,0 mmol/L～25 mmol/L,KOH淋洗液,流速为1.0 ml/min,电导检测器检测,样品经10000 rpm/min高速离心后用0.25μm滤膜过滤后直接进样。结果:本法线性相关性好(r≥0.9994),精密度好(RSD<5.0%),样品加标平均回收率为87%～99%,最低检出量0.063μg/ml。结论:该法操作简单、快速、准确、灵敏、适用于大批血清样分析。     

改进的UPLC-MS/MS法测定尿中12种邻苯二甲酸酯代谢物

目的 为实现尿液样本中邻苯二甲酸酯(PAEs)代谢物的批量测定,对已有方法的固相萃取过程进行优化改进,建立尿中12种PAEs代谢物的超高效液相色谱串联质谱(UPLC-MS/MS)分析方法.方法 尿样(2 mL)经β-葡萄糖醛酸酶水解、强阴离子固相萃取柱富集、净化、2％甲酸甲醇溶液洗脱后,省略氮吹浓缩程序,将洗脱液直接稀...     

Maintaining steady state arterial alcohol levels in rats by using a physiologically based pharmacokinetic model.

An intravenous method of alcohol administration that maintains arterial alcohol concentrations (AACs) in rats at a prescribed level for a prolonged period was previously described. This method produced steady state AACs between 30 and 180 min after the start of the infusion, but it resulted in substantial overshoots in AAC initially. The present study was designed to achieve target AACs close to steady state more quickly while minimizing any overshoot. A physiologically based pharmacokinetic (PBPK) model of alcohol distribution and elimination was developed for male Wistar rats. Body weight was used to compute individualized infusion rate profiles that would achieve steady state AACs of 75, 150, and 250 mg%. Rats were chronically implanted with cannulae in the jugular vein (for alcohol infusion) and carotid artery (for blood sampling). Alcohol was administered according to the individualized infusion rate profiles. Blood was collected at intervals for AAC determination. The PBPK model-based infusion profiles achieved target AACs 5 min after the start of the infusion and maintained the AACs for 2 h. The AACs deviated an average of 4.9%, 5.1%, and 5.9% from target at the 75, 150, and 250 mg% levels, respectively. Through the application of a PBPK model, it is possible to achieve target AACs close to steady state more quickly in male Wistar rats and to minimize any overshoot in AAC. The PBPK model-based method seems to be improved over the earlier method. Maintaining steady state AACs in rats is useful for studies in which fluctuating alcohol levels may confound experimental results.     

新疆树莓果实营养成分及其提取物抗氧化性研究

目的分析新疆野生树莓果实营养成分,并对其提取物进行抗氧化活性测定。方法进行营养保健成分含量分析,并对果实95%乙醇提取物经石油醚脱脂后,依次用乙酸乙酯、正丁醇萃取,观察不同萃取部位对DPPH·和·OH的清除能力。结果树莓鲜果中必需氨基酸含量高达320mg%,非必需氨基酸中谷氨酸含量较高(180mg%);富含维生素C(28.04mg%)和钾(147.32mg%);有机酸含量高达1.72%,以柠檬酸为主;其它如总酚、总黄酮、鞣化酸、单宁含量分别为498、125、2.2和290mg%,SOD活性高达606.93U/ml。树莓不同提取物均显示了较好的抗氧化活性,以乙酸乙酯部分最高,与清除DPPH自由基相比,清除羟自由基能力强。结论新疆野生红树莓果富含多种营养保健成分和抗氧化活性,有很好的开发价值。     

Generation of controlled atmospheres for the determination of the irritant potency of peroxyacetic acid

Given the physical properties of peroxyacetic acid, which decomposes into acetic acid and hydrogen peroxide, the generation and analysis of controlled atmospheres used to test the irritant potency of this peracid in mice require specific developments. The sampling and analytical method was based on the simultaneous sampling on a titanyl sulphate-impregnated silica gel tube (allowing the determination of total peroxides, peroxyacetic acid and hydrogen peroxide) and in an impinger containing a methyl-p-tolyl sulphide solution (of which the analysis yields the concentration of total acids, peroxyacetic acid and acetic acid, and peroxyacetic alone). From these results the concentrations of the different products can be inferred without interference. A special device composed of inert materials was designed for the generation of the controlled atmosphere. Buffering the peroxyacetic solution at pH 7 with a phosphate buffer allowed the generation of peroxyacetic acid atmospheres with negligible concentrations of acetic acid and hydrogen peroxide.     

2-(2-喹啉偶氮)-1,3-二羟基苯固相萃取分光光度法测定环境样品中钒的研究

根据新试剂 2 (2 喹啉偶氮 ) 1,3 二羟基苯 (QADHB)与钒的显色反应及C1 8固相萃取小柱对显色络合物的固相萃取 ,建立了一种测定环境样品中痕量钒的新方法 ,在pH 3 5的柠檬酸 -氢氧化钠缓冲介质中 ,溴化十六烷基三甲基铵 (CTMAB)存在下 ,QADHB与钒反应生成 2∶1稳定络合物 ,该络合物可用C1 8固相萃取小柱富集 ,小柱上富集的络合物用乙醇 (内含 2 %乙酸 )洗脱后用分光光度法测定 ,在富集后的测定液中 ,络合物最大吸收波长为 5 5 2nm ,摩尔吸光系数ε=8 2 9ⅹ 10 4 L·moL- 1 ·cm- 1 ,钒含量在 0～ 1 0 μg ml内符合比尔定律。方法用于几种环境样品中钒的分析 ,结果令人满意