sample consists of two parts, the matrix which is the substance to be determined, and the rest of the sample which comprises the yte.
where the aim is to identify or detect the presence of a species qualitative ysis is carried out. in circumstances where the amount of a substance present is measured, quantitative ysis is used.
重量法、容量法、光谱法和质谱法都是分析方法，不是分析技术。
在确定环境分析目标时，分析化学家最好与环境科学家有一个充分的协商。
sampling can be ided into following types: hypothesis guided sampling，random sampling，systematic sampling and stratified sampling
standard materials used should have a composition, which is closely similar to the sample, both its yte concentration and matrix.
write down the definition and characteristics of environmental ytical chemistry.
what is the principal factors underlying some very difficult problems to ytical chemists in environmental ytical?
write down the stages of overall ytical process in an environmental investigation.
how to select an ytical method？
for any measurement there is an ultimately correct value which is known as the .
is simply the difference between an experimental result and the true result.
the closeness of an experimental result to the true result is known as its .
the closeness of an experimental result to another experimental result is known as its .
applies when time and place and other circumstances may differ substantially, but with the method remaining ostensibly the same.
the numerical difference between the highest and lowest values in a data set is known as its .
the arithmetic average of a set of data is known as its .
in a set of data of 2.9, 5.7, 3.8, 4.2, 7.7, 5.2, 9.4, the median is .
the precision is usually expressed by the .
indeterminate error can be traced to sources such as:
write down the definition and importance of speciation.
how many approaches are there in trace metal speciation? what is the advantages and disadvantages of each approaches?
write down the classical five-step sequential extraction approach.
how many approaches are there in trace metal speciation? what are the advantages and disadvantages of each approaches?
write down the definition and importance of speciation.
1. there are naturally occurring elements on the earth.
in biological systems elements can be basically grouped into .
the earth’s crust contains free trace elements.
the purposes for most water samples to be filtrated immediately following collection are to remove .
the most desirable features of sample digestion methods are： .
the ytical techniques for measuring trace elements in environmental samples include:
in plant and animal systems, is it the same of the definition and inclusion for essential elements? why?
what are the most desirable features of sample dissolution procedure?
what are the characteristics of ideal ytical technique for measuring trace elements in environmental samples?
write down the approaches of determination of trace elements in environmental sample. what are their limitations? how to reduce or eliminate these problems?
what are the factors that affect the choice of ytical method for making trace element measurements of environmental or biological samples?
in general, the first common step in most protocols for sample preparation is .
hplc is of most utility where the organic ytes have .
what constitutes the environment？
what constitutes the pollutant?
what should we pay attention to when sample preparation?
the term ecotoxicology is used to define the branch of toxicology concerned with the study of the effects of natural and man-made (anthropogenic) substances on the biotic (living) and abiotic (non-living) components of the biosphere
ecotoxicological effects can be broadly classified as .
how to define the ecotoxicology and its extension?
briefly summarize the elementary method about bioassays of toxicology. for example.
give the ecological risk assesent of toxicant in living organi through vivid public crisis which happens at times around us.