A review on hyphenated techniques, with some advancement

1. REVIEW OF HYPHENATED TECHNIQUES
Bala Sunday Zeal
BUK

2. Hyphenated technique (HP Tech.) can be said to be the combination
(or) coupling of more than one different analytical techniques in a
single instrument with the help of proper interface and separation
proficiency.
In most common hyphenated techniques, mainly chromatographic
techniques are combined with spectroscopic techniques (Patel et al,
2010) e.g. the GC-MS or the LC-MS

3. It was first adapted by Hirsch Feld in 1980 to describe a possible
combination of two or more instrumental analytical methods in a
single run (Hirschfeld, 1980).
The aim of the coupling is to obtain an information-rich detection for
both identification and quantification compared to that with a single
analytical technique (Ruchira Chin hole et al, 2012). spitter,
sensitivity, flow-volume ratio, computer aided program

4. In recent years, hyphenated techniques have received ever-increasing
attention as a means to solve complex analytical problems.
The power of combining separation technologies with spectroscopic
techniques has been demonstrated over the years for both
quantitative and qualitative analysis of unknown compounds in
complex natural product extracts or fractions

5. Advances in the field of HP
Tech. has exceed coupling
two separation and detection
techniques, in the recent
time, there has been the
introduction of double
hybrid, also called triple
hyphenated techniques

7. Gas Chromatography – Mass Spectroscopy (GC-MS)
This is a hyphenated
technique developed from the
coupling of GC and MS. The
use of a mass spectrometer as
the detector in gas
chromatography was
developed during the 1950s
after being originated by
James and Martin in 1952.
(James et al, 1952)

8. GC-MS is a separation technique applicable to compounds which can
be volatilized in a gas stream
The advancement in GC/MS instruments using quadrupole
technology had become both essential to chemical research and one of
the foremost instruments used for organic analysis - identification of
molecular ion.
Used for confirmation of purity and identity of the components by
measuring exact mass and calculating elemental composition

9. Liquid Chromatography – Mass Spectrometry (LC-MS)
Definition…….
LC-MS is a chemistry technique that combines the physical separation of Liquid
chromatography (or HPLC) with the Mass spectroscopy (Sheetal et al.).
With advances
in HP tecs,
various types of
LC-MS systems
incorporating
different types
of interfaces are
available
commercially

10. Advances in HP Tech. with different interfaces are:
• Designed for adequate nebulization
• Vaporization of the liquid,
• Ionization of the sample
• Removal of the excess solvent vapor
• And extraction of the ions into the mass analyzer.

11. The widely used interfaces, especially in relation to natural product analysis:
• Electrospray ionization (ESI), and
• Atmospheric pressure chemical ionization (APCI).
The latter is considered as ''the chromatographer's LC-MS interface'' because
of its high solvent flow rate capability, sensitivity, response linearity, and fields
of applicability. With these interfaces, various types of analyzers, e.g.,
quadrupole, ion trap, or TOF, can be used

12. Liquid Chromatography – Nuclear Magnetic Resonance (LC-NMR)
As a result of advances in LC-
NMR, this method is a
powerful tool used in many
areas such as natural products,
organic molecules,
biomolecules, drug impurities,
by-products, reaction mixtures,
and drug degradation products
Direct coupling of liquid chromatography (LC) to NMR (Figure 5) using stop
flow method was reported in 1978 (John et al, 2000)

13. Recent advances in both hardware and software for the direct coupling of LC
and NMR have given a new life to this hyphenated technique.
Advances….
These advances include:
• A new coil and flow cell design for high sensitivity,
• New RF system for multiple solvent suppression
• Improved dynamic range gradient elution capability,
• Automatic peak-picking/storing capabilities.
Giving structural
imformation
no other techniques
can!!

14. Liquid Chromatography – Infrared Spectrometry (LC-IR)
LC-IR is a double hyphenated technique developed from the combination of LC
and the detection method infrared spectrometry (IR) or FTIR is known as LC-IR
or HPLC-IR

15. Important
For identification of organic compounds, because in the mid-IR region the
structures of organic compounds have many absorption bands that are
characteristic of particular functionalities, e.g., -OH, -COOH, and so on
Advances in FT-IR is in the geometry of the sample during the measurement
process, improving the signalto-noise ration by four times (Nagajyothi et al.).
This is because the IR detector is total light limited.

16. Capillary Electrophoresis – Mass Spectrometry (CE-MS)
The coupling of CZE
with electrospray
ionization mass
spectrometry (ESI-
MS), used particular
for obtaining
molecular mass
information and
structural details’

17. Most importantly…
Capillary electrochromatography (CEC) is another technique which is currently
undergoing a rapid phase of advancement and development, revived by
Jorgenson and Lukas in 1981
This technique has recently become more diffuse due to a number of advances in
both CE instruments and detection techniques. However, on-column UV
detection and in-column laser-induced Fluorescence detection remain the most
commonly used methods. Despite its high sensitivity, the latter method is
subjected to interferences by buffer Fluorescence (Levsen et al, 2005).

18. • The remarkable advances in HP Tech. analytical methods over the last two
decades have significantly broadened their applications in the analysis of
compounds.
• Advances in HP Tech. such as LC-MS, GC-MS, LC-NMR, CE-MS and ICP-
MS have been made to excellently solve various complex analytical problems
in different fields. These techniques solve such problems in time efficient
manner, higher degree of automation, higher sample throughput, better
reproducibility etc.