Instant Notes: Analytical Chemistry

one substituent present, and tables are given in standard spectrometry texts listing these. Identification of unknown organic sa ...

through the fluorescence of complexed species using fluorogenic reagents are given below in Table 3. Table 3. Examples of UV-vis ...

Calculate the concentrations of X and Y in the mixture. Using the Beer–Lambert law at each wavelength: A =eXcXl+eYcYl At 255 nm: ...

Section E – Spectrometric techniques E10 INFRARED AND RAMAN SPECTROMETRY: PRINCIPLES AND INSTRUMENTATION Principles The vibratio ...

However, when bonds are stretched they weaken, so a better model takes this into account, and the molecules are treated as anhar ...

or NIR radiation. If the exciting wavelength matches the energy difference between the electronic levels of the sample, the Rama ...

strength of bonds and their interaction. For analytical purposes, it is sufficient to note that there are 3N - 6 fundamental vib ...

spectrum, and therefore aqueous solutions may readily be studied. Overtones and combination vibrations occur less often. Vibrati ...

Vibrations that appear in the near infrared (NIR) region are the overtones and combination vibrations of those in the mid-IR. Th ...

exhaust gases may need a 10 m cell, which reflects the IR beam to achieve the long pathlength. Two points should be stressed if ...

solutions in solvents which do not absorb in the region of analytical interest, such as CCl 4 or CS 2 in NaCl cells, with a know ...

permits location of the area of interest using visible illumination, and which may then be altered so that the IR (or R) spectru ...

Section E – Spectrometric techniques E11 INFRARED AND RAMAN SPECTROMETRY: APPLICATIONS Comparison of the infrared (or Raman) spe ...

groups. With long chains, a weak band around 750 cm-^1 is due to rocking of the (–CH 2 – )ngroups. A similar spectrum is observe ...

shows the IR spectrum of a triglyceride fat, with the ester group R–O–CO–R¢. The long-chain of the carboxylic acid gives –CH str ...

be some differences, the major peaks are in similar positions, and some groups, such as substituted alkynes R–CC–R¢and –S–S–, gi ...

The second stage is to conduct a computer search of an appropriate database or library, for example of drugs, to test for an exa ...

of rocks, asbestos and to study residual solvents in pharmaceuticals. Mixtures can be analyzed directly, although chromatographi ...

Section E – Spectrometric techniques E12 NUCLEAR MAGNETIC RESONANCE SPECTROMETRY: PRINCIPLES AND INSTRUMENTATION Key Notes Nucle ...

Principles Nuclear magnetic resonance (NMR) transitions can be observed in the radio- frequency region of the electromagnetic sp ...