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welcome back to our channel friends
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foreign public desk india
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today's topic is micro crystalline test
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a commendable method
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equivalent to instrumental analysis
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let's proceed further
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introduction to micro crystalline test
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traditional light microscopy
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and micro crystal tests
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are very old and used since more than
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100 years
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these are proven useful when automated
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instrumental analysis are not available
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or the results are not appropriate if
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the mixtures of
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one or more drugs is mixed or there are
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adult trends in the drug
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still this test will work drug in
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different forms
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like gels transdermal patches the micro
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questions
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test will be useful in such kind of
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complications also
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some small scale forensic science
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laboratories may lack
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certain type of automated instruments
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most of them
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are having light microscopes and also
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personals and scientists
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but this instruments are not developed
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if they are having proper experience
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with microscopes
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and they know how to observe the
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crystals properly this is the most
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efficient one
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microcrystal tests use polarized light
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microscopy
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specially can identify most illicit
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drugs
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specifically and quickly usually within
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few minutes
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they are fast easy to perform and can be
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highly specific and inexpensive compared
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to other methods
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in addition proper use of light
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microscopy
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and crystal tests can check and confirm
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the results obtained by alternative
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methods
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i have provided a link in the
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description where it ha
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describes about polarized light
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microscopy that is of nikon
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and it is worth watching applied for
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crystals
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and its observation so
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micro crystal test techniques are based
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on highly developed
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chemical precipitation reactions in
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which a polarized microscope is used to
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observe
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distinguish the different types of
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crystals formed
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microcrystal tests are conformatory
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tests often used to verify the results
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of pulmonary screening methods
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in history microcrystalline tests are
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used to confirmation of sample
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identification after doing a color test
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and now it is still considered as a
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confirmation test
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but it is a wet lab method currently
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instrumental method analysis are
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considered as more specific
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and for accurate positive results
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though we have microcrystalline tests we
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have to use instrumental methods
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to give positive confirmation of
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identification which could be much
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appropriate to submit a computerized
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report than a manual report which is
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produced by our
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microcustomers microcrystal analytical
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process
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is a different procedure of chemistry
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compared with any other types
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like color test we can see this
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particular subject needs expertise and
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skills to interpret the complicated
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results
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as such of crystals
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coming to advantages of microcrystalline
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techniques
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as i already said this method is
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inexpensive
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we will need only pure reagent
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microscopes and
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some basic lab apparatus it can be
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referred as an
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alternative to gcms and fdi and these
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are very sophisticated instruments for
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analysis
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micro crystal tests are also environment
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friendly
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where there is no much hazardous part
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involved
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until and unless the apparatus are
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mishandled test procedure also consumes
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very less amount of reagent than
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reagents which we
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consume to conduct instrumental analysis
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there is no requirement of purification
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for the compounds for analysis
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this method is highly specific and
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crystals are uniquely formed
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only to specific reagents it should be
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noted that microcrystalline formation
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does not affect the chemical and
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physical properties of substance this is
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an
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advantage so that you can use this
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particular
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sample which is been done for micro
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crystal where you are adding the reagent
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and you can do the instrumental analysis
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further
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one of the important advantage is that
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the compounds with different
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optical isomerism exhibit similar kind
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of chemical and physical properties
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and at that time differentiation would
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not be possible
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unless we when we are using polarimeter
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so in this case test different
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optical isomerisms exhibit different
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crystal formations
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hence we can differentiate the compounds
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easily
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sometimes the isomer may be a drug but
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its complementary isomer may not be a
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drug
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so identification of isomer is also
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crucial
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which can attain by this
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coming to disadvantage of micro
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crystalline techniques
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the principal disadvantage of micro
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crystalline testing is that it is not
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applicable to all substances
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crystal testing procedures do not exist
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for a number of commonly encountered
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controlled substances and chemicals
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microcrystal
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testing can produce more than one type
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of arrangement
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presence of additional crystal forming
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agents may interfere
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the precipitation of target compound
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this interference may cause either
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distortions
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or variations in the expected crystal
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form
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that is also known as polymorphism
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this may complicate the identification
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process in such cases a purification
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procedure
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is need to be done by thin layer
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chromatography or any extraction method
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this is recommended before micro
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crystalline analysis has been done
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the formation of solid crystalline
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solution begins
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when individual molecule or ions
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clustered together
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this process of nucleation continues
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until a visible particle appears
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in a crystal formation if the
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sample material is having high
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concentration then there is a fast
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formation of crystal
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which will engulf the debris in the
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subject and there will be distortion in
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the crystal observation
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it will be not visible very clearly if
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it is having many debris or if it is
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having
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high concentration therefore it is
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required to pre-process the sample
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if it is concentrated in the nature
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so it is need to be pre-processed even
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though
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there is a point in advantages saying
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that no purification is required
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though there are standards available to
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conf to compare
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and identify this crystals formed this
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process and interpret
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interpretation of outcomes completely
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depend upon the expertise of personal
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doing the
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test they should be having proper
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capabilities to differentiate polymorph
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crystal and identify individual
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compounds from a mixture
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if the sample is contaminated
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microcrystalline tests lack versatility
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due to which it is not suitable for
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quantization and
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documentation it is a special test which
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needs
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much attention and proper standards
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micro crystal test techniques this is
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the procedure
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test sample is added with sufficient
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amount of reagent
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and there are some factors which should
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be
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considered while doing this test like
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sometimes we need to
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apply high temperature that means after
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putting the
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the sample and the reagent on the slide
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we have to heat the slide
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or sometimes it need to be kept in the
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refrigerator to cool the temperature
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or sometimes there is a requirement of
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acid or bases
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in the reagent so that ph is maintained
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so these are the factors
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uh part of preprocessing when
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the sample is reacting with the reagent
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there is formation of
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solid why solid will be formed
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molecules or ions cluster together
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nucleation continues until a visible
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particle appears
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in a crystal formation this crystal
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formation is unique
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by its unique nature only we will be
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able to identify
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the sample okay this can be understood
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in
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three broad categories that is first one
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aqueous techniques
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aqueous technique is very simple take
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the sample on the slide
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take the rear joint on the slide but
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separately two different tops are taken
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separately like this
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the sample reagent and the reagent
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sample and the reagent separately are
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taken and kept under the microscope
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this two will be mixed under the
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microscope itself
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and you will be observing the formation
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of crystals under the microscope
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immediately while reaction is occurring
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there is no requirement of coverslip for
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this
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so if you are doing late what will
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happen
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the saw crystals will form and the
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complete sample will
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solidify and you will be unable to
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identify what type of
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crystal it is next one volatility
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technique in volatility technique we are
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going to use
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the slide which is having depression to
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it
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that means hanging drop slide
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so in this depression we are going to
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introduce the sample
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and the sample nature here is volatile
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so the volatile sample is going to
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release vapors
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so that is what our principle
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is here take a cover slip on that
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coverslip you place the reagent
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and put the reagent over this depression
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so there will be
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some air gap between the actual sample
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and our reagent they are not going to
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get mixed
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so in that air gap the vapors which are
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released by the sample
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are going to react with the reagent
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when it is going to react with the
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reagent there are crystal forms
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formations which are seen on the
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coverslip that can be observed from a
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microscope so these crystals can be
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unique and you can identify them
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there is one more type of test that is
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acid anionic test technique
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this is the combination of aqueous and
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volatility technique
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a sample is placed in the cavity or the
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depression
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of a slide a drop of alcohol solution
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methanol or ethanol is added one drop of
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reagent is added
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immediately after the alcohol and cover
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slide is
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placed over the cavity to prevent
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evaporation
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crystal formation is observed by placing
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the cavity slide
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with cover directly under a microscope
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this technique is often used to
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crystallize steroid hormones
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barbiturates
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including phenobarbital coming to
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volatility technique
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this is applied for observation of
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volatile compounds like
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aldehydes and ketones and also secondary
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amines
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so these are the few examples of micro
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crystals which are formed and
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the photographs are taken from the
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microscope
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so as like i already said microscope
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which is use this
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pluralized microscope and sometimes we
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can also use
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dark field microscope normal white light
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microscope also to absorb this
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crystals for more clarity for realized
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micro microscope pieces
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then these images are taken from a
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macron
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research institute they have given a
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very good report
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where all illicit drugs are tested micro
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crystalline tests
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and they have given different types of
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crystals so this
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particular report is used as reference
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by many scientists who are doing the
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narcotic drug analysis
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or psychotropic drug analysis so let us
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go into this mdma it is going to form
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x type of crystals this these are one
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kind of
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crystals which are formed
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by reacting with gold chloride so second
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one method on
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this is formed into rosette crystals
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these are rosette crystals
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which are able to see here by reacting
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with mercuric chloride
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these are cloth spins you can see this
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shape is different from this this one
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and
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this is a d methamphetamine as like i
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already said
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optical isomers can also be identified
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so this crystals are formed only to
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d methamphetamine not for l type
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okay next we are having morphine
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morphine is going to form
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a droplet kind of crystals these
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crystals are little clumsy and
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it is formed by glo gold bromide you can
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see
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all the four reagents which are used
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here are a metal
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with highlight combination and here also
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we are having the same thing
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oxycodone it is also forming a certain
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kind of
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crystals which can be said as rosettes
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or it can also be uh tuft or bur
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so this type of crystals are formed by
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oxycodone
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then pseudoephedrine a natural drug
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it is been formed into tablets so these
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particular structures can be referred as
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tablets or plates so
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this crystals are formed by deleteric
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acid reacting with
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pseudoephedrine and this one is cylosine
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trinitrobenzoic acid is the reagent used
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fan crystals so we can see fan crystals
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here
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these are very unique all drugs which i
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have seen
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among all cylosine is very unique
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crystal which is formed
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so that is a psychotropic drug coming to
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cocaine
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using a gold chloride gold chloride is
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already seen in d methamphetamine
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same reagent is again used for cocaine
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in
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methamphetamine we are going to see
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cloth spins but in a cocaine we are
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going to see
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x-shaped crystals but this crystals are
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very unique very
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good design will be there if you see
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this particular image
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i am going to give you the link in the
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description you just click on the link
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you will be going into the
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pdf file that is the report of this
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micro crystalline test so that you will
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be understanding all micro crystalline
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tests
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then diazepam a chemical of
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benzodiazepines family and this is a
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using
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ammonium theocyanide so it is just like
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a glass fracture that kind of uh with a
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micro crystal is there but it is called
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as rosette type
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rosette type is here and again uh heroin
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you can see mercury chloride
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so mercury chloride it is repeated for
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the second time
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so we have already used it for methadone
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it is forming rosettes
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and for heroin it is forming feathery
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dendrites
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so if you are seeing this too it is
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little uh
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confused it is also almost similar but
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you need to identify carefully
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it is having feathery feathery kind of
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crystals are formed
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but here it is rosette type process type
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means you can see
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very particularly all are spreaded like
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a star but here it is feathery type so
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these are the types of crystals
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and a very important tracks which are
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been identified by using
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the generally
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combination of metals and highlights
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that is commonly which we have seen
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[Music]
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[Music]
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[Music]
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thank you for watching friends i hope
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this video was useful for you micro
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crystalline tests are very important
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and in very first slide itself i have
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said you that
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it is almost equivalent to instrumental
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analysis but
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micro crystalline tests are limited
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because very few procedures are
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available for very few chemicals
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but instrumental methods of analysis we
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can do any type of material
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for examination and it will be very
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helpful and the computerized
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reports will be produced by that
