CH3

的

< br>1HNMR

信号

.

5.

可以把三个成分作为

100%(

假定样品中几 乎没有水分和无机成分

),

也可以计算

%.

方法是比较灵活的

.

特殊情况的 问题再叙

.

此法比较方便快捷，误差通常在可接受的范围，当 然没有色谱法精度高。

1HNMR

不但可以测定混合物中成分的相对含量

,

也可以通过加入合适的内标测定绝对含量

,

有很多文献

.

有个术语叫

Quantitative NMR(QNMR).

国外有

1HNMR

< br>定量测定天然混合物的论文和综述文章

.

比如

:

Based

on

a

brief

revision

of

what

constitutes

state-of-the-art

experimental

conditions

references and covers the literature since 1982 with emphasis on natural products. It provides an

overview

of

the

background

and

applications

of

qHNMR

in

natural

products

research,

new

methods

such

as

decoupling

and

hyphenation,

and

analytical

potential

and

limitations,

and

compiles information on reference materials used for and studied by qHNMR. The dual status of

natural products, being single chemical entities and valuable biologically active agents that need

to

be

purified

from

complex

matrixes,

results

in

an

increased

analytical

demand

when

testing

their

deviation

from

the

singleton

composition

ideal.

The

outcome

and

versatility

of

reported

applications lead to the conclusion that qHNMR is currently the principal analytical method to

meet this demand. Considering both 1D and 2D 1H NMR experiments, qHNMR has proved to be

highly

suitable

for

the

simultaneous

selective

recognition

and

quantitative

determination

of

metabolites in complex biological matrixes. This is manifested by the prior publication of over 80

reports

on

applications

involving

the

quantitation

of

single

natural

products

in

plant

extracts,

dietary materials, and materials representing different metabolic stages of (micro)organisms. In

summary, qHNMR has great potential as an analytical tool in both the discovery of new bioactive

natural products and the field of metabolome analysis.

1HNMR

法定量测定替米考星的 含量的论文摘要

(

分析测试学报

)

。

----------------- ------------------------

Historical Background of qNMR. Quantitative NMR (qNMR) is almost as old as NMR itself. Early

reports

regarding

the

achievable

precision

of

quantitation

are

inconsistent,

and

some

of

them

even tended to deny NMR a role as a precision method by estimating the error to be in the 10%

range.

Interestingly,

and

with

notable

exceptions,textbook

literature

often

does

not

emphasize

the

quantitative

aspects

of

NMR

and,

thus,

does

not

motivate

educators

and

researchers

to

consider

qNMR

as

an

analytical

tool.

This

stands

in

contrast

to

the

authors'

recent

personal

discussions

with

experienced

NMR

spectroscopists,

as

well

as

to

the

tenor

of

the

publications

cited

in

this

review,

according

to

which

the

quantitative

power

of

1H

NMR

and

its

broad

applications

are

greatly

underestimated.

Moreover,

recent

developments

in

the

field

have

provided evidence that NMR can be developed as a precise quantitative tool and, in time, can

even be a primary analytical method.

As can be seen from Figure 1, there is

a steadily increasing interest in qNMR over the past 40

years,

as

measured

by

the

number

of

publications

in

the

field

(Chemical

Abstracts).

However,

taking

into

account

the

overall

rapid

increase

of

publications

in

science,

and

especially

when

considering the statistics for natural products related qNMR (solid bars in Figure 1), there seems

to

be

almost

no

gain

in

interest

in

the

past

15

years,

a

period

that

has

been

exceptionally

productive

in

terms

of

NMR

hardware

development.

It

must

be

noted,

however,

that

the

metabolomic

studies

mentioned

below, which

often

involve

(semi-)

quantitative NMR

analysis,

are

not

included

in

this

statistical

picture,

because

the

necessary

qNMR

keywords

cannot

be

searched successfully since they are not included in the database entries of the corresponding

publications.

The

importance

of

the

qNMR

methodology

in

this

recently

emerging

area

of

research,

however,

indicates

the

rising

impact

of

qNMR

methodology

on

natural

products

research in general.

------ --------------------------------------------------

Literature

Background

of

qNMR.

Because

qNMR

has

been

living

in

the

shadow

of

the

multifaceted

and

multidimensional

qualitative

NMR

used

in

structure

analysis,

neither

has

it

been used as widely and routinely nor is a recent and comprehensive overview of the literature

available.

However,

Szantay

and

Evilia

have

reviewed

systematically

the

general

experimental

factors

known

to

interfere

with

quantitative

determinations

in

NMR.

Their

articles

cover

relaxation, digitization, and instrumental parameters and provide valuable sources of information

independent

from

the

observed

nuclei.

Certainly

noteworthy,

while

exclusively

dealing

with

analyses of drugs and pharmaceuticals, is the extensive qHNMR work by Turczan and co-workers

at

the

FDA,

which

to

our

best

knowledge

has

not

been

summarized

in

a

review

format.

Their

experience shows that typical errors fall in the 0.5-2% range, and their reports serve as a valuable

resource when it comes to the selection of qNMR reference standards (see below). The essential

lack of reports describing the application of qHNMR in natural product research is confirmed in a

1989

1H/13C

NMR

review

by

Pieters

and

Vlietinck,

who

concluded

that,

despite

the

great

potential of qNMR, suitability has to be established for each individual case. The excellent review

series focused on 1H NMR by Rackham that begun in 1975, unfortunately, has been discontinued,

leaving almost all of high-field qHNMR uncovered. The present review seeks to fill this gap and to

provide a comprehensive survey of the qHNMR literature by discussing recent and forthcoming

technological innovations, while concentrating on the applications of qHNMR to complex samples

(mixtures) such as materials that are obtained from natural sources. Because the second most

studied

organic

NMR

nucleus

(13C)

is

considerably

less

sensitive

(1.6%

of 1H

sensitivity

for

an

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