药学英语Unit 8 Text A 注释及译文

Text A What Analytical Chemists Do

Analytical chemistry is concerned with the chemical characterization of matter

and the answers to two important questions: what is it (qualitative) and how much is it

(quantitative). Chemicals make up everything we use or consume, and knowledge of

the chemical composition of many substances important in our daily lives. Analytical

chemistry plays an important role in nearly all aspects of chemistry, for example,

agricultural, clinical, environmental, forensic, manufacturing, metallurgical, and

pharmaceutical chemistry. The nitrogen content of a fertilizer determines its value.

Foods must be analyzed for contaminants (e.g., pesticide residues) and for essential

nutrients (e.g. vitamin content). The air in cities must be analyzed for carbon

monoxide. Blood glucose must be monitored in diabetics (and, in fact, most diseases

are diagnosed by chemical analysis). The presence of trace elements from gun powder

on a murder defendant’s hand will prove a gun was fired. The quality of manufactured

products often depends on proper chemical proportions, and measurement of the

constituents is a necessary part of quality control. The carbon of steel will determine

its quality. The purity of drugs will determine their efficacy.

1、qualitative ['kwɔlitətiv, -tei-] adj.

定性的；质的，性质上的

2、quantitative ['kwɔntitətiv, -tei-] adj. 定量的；量的，数量的

3、consume [kən'sju:m]vt.

消耗，消费；使…著迷；挥霍

vi. 耗尽，毁灭；耗尽生命

4、analytical [,ænə'litik,-kəl] adj.

分析的；解析的；善于分析的

5、forensic

[fɔ'rensik] adj.

辩论的；法院的；适于法庭的

6、metallurgical [,melə'lə:dʒik,-kəl] adj.

冶金学的；冶金的

7、nitrogen ['naitrədʒən] n. [化]氮

8、contaminant [kən'tæminənt] n.

污染物；致污物

9、pesticide residues ['pestisaid] ['rezɪ,du:, -,dju:]杀虫剂残留

10、carbon monoxide [无化] 一氧化碳

11、glucose ['ɡlu:kəus]n.

葡萄糖；葡糖（等于dextrose）

12、diabetic [,daiə'betik] adj. 糖尿病的，患糖尿病的 n. 糖尿病患者

13、defendant [di'fendənt] adj.

为自己辩护的；辩护的 n.

被告

14、constituent [kən'stitjuənt]n. 成分；选民；委托 adj. 构成的；选举的

分析化学研究物质的化学成分，并且要解决两个问题：样品里有什么化学物质（定性），化学物质的量有多少（定量）。在我们的日常生活中，化学物质无处不在，因而了解各种物质的化学成分非常重要。分析化学对于化学的各个领域的应用，例如化学在农业、临床医学、法医学、制造业、冶金和药学领域的用，都非常重要。化肥的氮含量决定其效价。对于食品，要检查其是否被污染（例如农残），并测定其中必需营养物质（例如维生素）的含量。而一氧化碳含量是城市空气质量的重要指标。对于糖尿病患者（事实上许多疾病的诊断要依靠化验）监测血糖含量非常重要。如果通过分析化验发现谋杀嫌犯手上有火药残留的痕迹，则可以证明他（她）开过。产品质量的好坏往往其中各种化学成分的比例是否适当密切相关，因而测定产品中各种化学成分的比例是产品质控必不可少的一项工作。钢铁的碳含量多少决定其质量的优劣。药物的纯度影响其疗效。

What is Analytical Science?

The above description of analytical chemistry provides an overview of the

discipline of analytical chemistry. There have been various attempts to more

specifically define the discipline. The late Charles N. Reilley said: “Analytical

chemistry is what analytical chemists do.” The discipline has expanded beyond the

bounds of just chemistry, and many have advocated using the name analytical science

to describe the field. This term is used in a National Science Foundation report from

workshops on “Curricular Developments in the Analytical Science.” Even this term

falls short of recognition of the role of instrumentation development and application.

One suggestion is that we use the term analytical science and technology.

1、advocate ['ædvəkeit, 'ædvəkət] vt.

提倡，主张，拥护n.

提倡者；支持者；律师

2、curricular [kə'rikjulə] adj. 课程的

3、short of

缺乏；不足；除…以外

4、recognition [,rekəg'niʃən] n.

承认，认出；赞誉；重视；识别；公认

5、instrumentation [,instrumen'teiʃən, ,instrə-] n. 乐器法；使用仪器；仪表化

通过上面的描述，我们对分析化学这个学科有了大概的了解。许多人试图对分析化学更为具体的定义。已故的著名学者Charles N. Reilley说：分析化学就是分析化学家从事的工作。这个学科的发展已经超出了化学的范畴，因此许多人建议用分析科学来描述这一领域。在一个关于“分析科学的课程建设”的专题研讨会上有一篇关于自然科学基金报告上使用过这个术语。但是，即便是采用这个术语也不足以体现新仪器的应用对分析化学的重要意义，因此有人建议使用“分析科学和技术”这个术语。

The Federation of European chemical societies held a contest to define

analytical chemistry, and the following suggestion by K. Cammann was selected.

Analytical chemistry provides the methods and tools needed for insight into our

material world … for answering four basic questions about a material sample:

What?

Where?

How much?

What arrangement, structure or form?

1、federation ['fedəreiʃən] n. 联盟；联邦；联合；联邦政府

欧洲化学学会联合会对分析化学的定义有不同的看法， 该学会的K.

Cammann对分析化学的定义如下：

分析化学为我们深入的了解物质世界提供了方法和工具。分析化学要解决以下四个基本问题：

样品里有那些化学物质？

这些物质如何分布？

它们的含量是多少？

这些物质是怎么排列的，组成什么样的结构？

The Division of Analytical Chemistry of the American Chemical Society

provides a comprehensive definition of analytical chemistry, which may be found on

their website. It is reproduced in most part here:

Analytical chemistry seek ever improved means of measuring the chemical

composition of nature an artificial materials. The techniques of this science are used

to identify the substances which may be present in a material and to determine the

exact amounts of the identified substance.

1、reproduce [,ri:prə'dju:s] vt.

复制；再生；生殖；使…在脑海中重现

vi. 繁殖；复制

美国化学会分析化学分会对于分析化学给出了一个全面的定义，我们可以在其网站上到这个定义。现将其大部分摘录如下：

分析化学就是要不断的改进确定天然的和人工合成物品的有哪些化学物质方法和测定这些物质含量的方法。运用分析化学的技术，我们可以确定物品中有哪些化学物质并且测定这些物质的准确含量。

Analytical chemists work to improve the reliability of existing techniques to

meet the demands for better chemical measurements which arise constantly in our

society. They adopt proven methodologies to new kinds of materials or to answer new

questions about their composition and their reactivity mechanisms. They carry out

research to discover completely new principles of measurement and are at the

forefront of the utilization of major discoveries, such as lasers and microchip devices

for practical purposes. Their efforts serve the needs of many fields:

●

In medicine, analytical chemistry is the basis for clinical laboratory tests

which help physicians diagnose disease and chart progress in recovery.

●

In industry, analytical chemistry provides means of testing raw materials and

for assuring the quality of finished products whose chemical composition is critical.

Many household products, fuels, paints, pharmaceuticals, etc. are analyzed by the

producers developed by analytical chemists before being sold to consumers.

Environmental quality is often evaluated by testing for suspected contaminants

using the techniques of analytical chemistry.

The nutritional value of food is determined by chemical analysis for major

components such as protein and carbohydrates and trace components such as vitamins

and minerals. Indeed, even the calories in a food are often calculated from its

chemical analysis.

Analytical chemists also make important contributions to fields as diverse

forensics, archaeology, and space science.

1、chart [tʃɑ:t] n. 图表；海图；图纸vt. 绘制…的图表；在海图上标出；详细计划

2、archaeology [,ɑ:ki'ɔlədʒi] n. 考古学

分析化学家致力于提高已有技术的可靠性以满足社会上对化学物质分析检测的不断提高的要求。他们将已证实的方法应用于新型材料，或者回答关于其组成及反应机制的新问题。他们进行研究，探索分析检测的新原理；他们立足于科技进步的最前沿，尝试尖端的科学技术，例如激光和芯片，在分析化学领域的实际应用。分析化学应用的领域非常广泛：

在医学领域，分析化学是化验的基础，化验可以帮助医生诊断疾病和判断病人恢复健康的程度。

在工业领域，应用分析化学的方法可以对原材料和对化学组分的配比有严格要求的成品质量进行把关。许多日常生活用品，例如燃料、涂料和药品等等，都是经质检合格后才能销售的。

应用分析化学的方法检测可疑污染物是环境质量评估的依据。

通过检测食物中主要成分的含量，例如蛋白质和碳水化合物，和微量成分的含量，例如维生素和矿物质，可以评价食物的营养价值。

分析化学家在法医学、考古学和太空学等多个领域也作出了重要贡献。Qualitative and Quantitative Analyses: What Does Each Tell Us?

The discipline of analytical chemistry consists of qualitative analysis and

quantitative analysis. The former deals with the identification of elements, ions, or

compounds present in a sample (we may be interested in whether only a given

substance is present), while the latter deals with the determination of how much of

one or more constituents is present. The sample may be solid, liquid, gas, or a mixture.

The presence of gunpowder residue on a hand generally requires only qualitative

knowledge, not of how much is there, but the price of coal will be determined by the

percentage of sulfur impurity present.

1、sulfur ['sʌlfə] vt.

用硫磺处理n.

硫磺；硫磺

分析化学包括定性分析和定量分析两个方面。定性分析要解决的问题是样品里含有哪些元素、离子或化合物（我们关心的可能只是某种特定的物质），而定量分析要解决的问题是样品中一个或多个组分的含量究竟是多少。样品可能是固态，液态，气态或混合物态。进行火药残留检验，定性就足够了。但是煤炭中硫磺杂质百分含量具体是多少，与其经济价值密切相关。

Qualitative test may be performed by selective chemical reactions or with the

use of instrumentation. The formation of a white precipitate when adding a solution of

silver nitrate to a dissolved sample indicates the presence of chloride. Certain

chemical reactions will produce colors to indicate the presence of classes of organic

compound, for example, ketones. Infrared spectra will give “fingerprints” of organic

compounds or their functional groups.

1、precipitate [pri'sipitit, -teit]n.

沉淀物 vt.

使沉淀；促成；猛抛；使陷入

vi. 猛地落下；沉淀；冷凝成为雨或雪等adj.

突如其来的；猛地落下的；急促的

2、ketone ['ki:təun] n. [化]酮

3、Infrared Spectra ['infrə'red] ['spektrə] 红外光谱 ；偏振近红外谱 ；近红外谱

样品中化学物质的定性鉴别可以通过具有选择性的化学反应或使用仪器来实现。向样品溶液中加入硝酸银溶液，如果产生白沉淀则表明样品中有氯离子存在。具有某种官能团的一类化合物，例如酮类，的选择性化学反应可以产生颜变化，凭此可对其定性鉴别。红外光谱中可以反应出某种有机化合物或者其官能团特有的信息，从而对其定性鉴别。

A clear distinction should be made between the terms selective and specific:

● A selective reaction or test is one that can occur with other substances but

exhibits a degree of preference for the substance of interest.

● A specific reaction or test is one that occurs only with the substance of interest.

Unfortunately, few reactions are specific but many exhibit selectivity.

Selectivity may be achieved by a number of strategies. Some examples are:

●

Sample preparation (e.g., extractions, precipitation)

●

Instrumentation (selective detectors)

●

Target analyte derivatization (e.g., derivatize specific functional groups with

detecting reagents)

●

Chromatograph, which provides powerful separation

1、preference ['prefərəns] n.

偏爱，倾向；优先权

2、precipitation [pri,sipi'teiʃən] n.

坠落；沉淀，沉淀物；鲁莽；冰雹

3、derivatization

[di'riveitaiziʃən]n.

衍生；衍生化；衍生化作用

derivatize

[di'riveitaiz] vi. [生物化学] 衍生化

我们应该深刻理解“选择性的”和“专属的”的区别：

●

某种或某类化合物的选择性化学反应或者选择性分析方法是指对目标化合物很灵敏的反应或方法，从而实现定性鉴别。其他化合物虽然也能发生这样的反应或者对这样的方法有响应，但灵敏度要差很多。

●

专属性化学反应或分析方法的特点是只对目标化合物有响应。

但是，事与愿违，选择性化学反应很多，达到选择性的方法也很多，而专属性反应则寥寥无几。例如：

●

通过样品制备方法实现选择性（例如采用提取或产生沉淀的方法）。

●

通过仪器实现选择性（具有选择性的检测器）。

●

通过将目标化合物衍生化实现选择性（例如使用检测试剂将目标化合物的某种功能基团衍生化）。

●

通过利用谱法强大的分离能力将目标化合物分离。

For quantitative analysis, a history of the sample composition will often be

known (it is known that blood contains glucose), or else the analyst will have

performed a qualitative test prior to performing the more difficult quantitative

analysis. Modern chemical measurement system often exhibit sufficient selectivity

that a quantitative measurement can also serve as a qualitative measurement. However,

simple qualitative tests are usually more rapid than quantitative procedures.

Qualitative analysis is composed of two fields: inorganic and organic. The former is

usually covered in introductory chemistry course, whereas the latter is best left until

after the student has had a course in organic chemistry.

1、inorganic [,ɪnɔ:'gænɪk] adj.

无机的；无生物的

2、organic

[ɔ:'ɡænik] adj. 有机的；器官的；组织的；根本的

对以定量分析，样品中含有哪些成分往往是已知的（例如，众所周知，血

液中含有葡萄糖），否则在进行比较复杂的定量分析之前，要先进行定性鉴别。现代的化学分析方法往往具有很高的灵敏度，因而定量分析方法也能实现定性分析。但是定性鉴别方法的优点是简便、快捷。定性分析包括无机和有机两个方面。无极定性分析往往是基础化学课程的一部分，而有机定性分析放在有机化学以后学习效果肯能更好。

In comparing qualitative versus quantitative analysis, consider, for example, the

sequence of analytical procedures followed in testing for banned substances at the

Olympic Games. The list of prohibited substances includes about 500 different active

constituents: stimulants, steroids, beta-blockers, diuretics, narcotics, analgesics, local

anesthetics, and sedatives. Some are detectable only as their metabolites. Many

athletes must be tested rapidly. And it is not practical to perform a detailed

quantitative analysis on each. There are three phase in the analysis: the fast-screening

phase, the identification phase, and possible quantification phase. In the fast-screening

phase, urine samples are rapidly tested for the presence of classes of compounds that

will differentiate them from “normal” samples. Various techniques include

immunoassays, gas chromatography, and liquid chromatography. About 5% of the

samples may indicate the presence of unknown compounds that may or may not be

prohibited but need to be identified. Samples showing a suspicious profile during the

screening undergo a new preparation cycle (possible hydrolysis, extraction,

derivatization), depending on the nature of compound that have been detected. The

compounds are then identified using the highly selective combination of gas

chromatography/mass spectrometry (GC/MS). In this technique, complex mixtures

are separated by gas chromatography, and then they are detected by mass

spectrometry, which provides molecular structural data on the compounds. The MS

data, combined with the time of elution from the gas chromatograph, provide a high

probability of the presence of a given detected compound. GC/MS is expensive and

time-consuming, and so it is used only when necessary. Following the identification

phase, some compounds must be precisely quantified since they may normally be

present at low levels, for example, from food, pharmaceutical preparations, or

endogenous steroids, and elevated levels must be confirmed. This is done using

quantitative techniques such as spectrophotometry or gas chromatography.

1、stimulant ['stimjulənt] n.

兴奋剂；刺激物；酒精饮料

adj. 激励的；使人兴奋的

2、steroids ['stiərɔidz] n.

类固醇（steroid的复数形式）；甾体

3、diuretics [,daiju'reitikz]

n. 利尿剂

4、narcotics [nɑ:'kɔtɪks]

n. 麻醉；麻醉剂

5、analgesics

[,ænəl'dʒi:zɪks, -sɪk],

n. 镇痛药；止痛剂

6、anesthetics [,ænɪs'θetɪks]

n.

麻醉药；麻醉剂

7、sedatives ['sedətivz]

n.

镇静剂；起镇静作用的东西

8、metabolites [mi'tæbəlaits]n.

代谢物；代谢分子

9、athletes ['æθli:ts]

n.

运动员；身强体健的人

10、immunoassays [,imjunəu'æsei]

n.

分析，免疫测定

11、chromatography [,krəumə'tɔɡrəfi] n.谱分析法

12、hydrolysis [hai'drɔlisis] n. [化]水解作用

13、mass spectrometry [mæs] [spek' trɔmitri ] 质谱分析法

14、elution [i'lu: ʃən]

n.

[分化] 洗脱；[冶] 洗提

15、elevated ['eliveitid] adj. 提高的；高尚的；严肃的；欢欣的

v.

抬起；提高；振奋；提拔（elevate的过去分词）

n.

[口]高架铁路

16、spectrophotometry [,spektrəufəu'tɔmitri] n.

分光光度法

让我们以奥运会违禁药物检查的操作流程为例对定性分析和定量分析进行比较。违禁药物共有500多种，包括兴奋剂，β-受体阻断剂，利尿剂，麻醉药，镇痛药，局部麻醉剂和镇静药。这其中有些药物只能通过其代谢物检测。因为需要在短时间内完成对大量运动员进行兴奋剂检查工作，因而不可能对每个样品都进行定量分析。违禁药物的检查包括三个阶段：快速筛选阶段，定性鉴别阶段，定量分析阶段（必要时才进行）。在快速筛查阶段要对运动员的尿样进行快速分析以确定其中是否疑似违禁药物。可用于这一阶段的检测技术很多，包括免疫测定法，气相和液相谱法等。大约有5%的样品中可能检出未知化合物，需要通过进一步检测，确定其化学结构以便判别其是否为违禁药物。对于可疑的样品应根据初步判断的化合物的类别对样品进行进一步的处理（水解，提取或衍生化）。然后通过高选择性的气质联用法确定可疑化合物的结构。气质联用法是通过气相

谱对成分复杂的混合物进行分离，然后再通过质谱法确定化合物的分子结构。将质谱数据与谱峰的保留时间相结合可以确定样品中含有某种化合物，这种方法的准确率很高。采用气质联用法不仅耗时而且价格昂贵，因此只有在必要时才使用。对样品中的可疑化合物进行结构确证之后，对于某些化合物要准确定量。因为在正常情况下体内也可能存在这些化合物，例如来自食物，非违禁药物或者本身就是自内源性类固醇，只是含量较低。因此有必要对这些化合物准确定量，以判断其含量是否升高。采用分光光度法或气相谱法等方法可对这些化合物准确定量。