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yashada ( zinc ) is one of the puti lohas ( metals with low melting points eg lead , tin etc . ) .
its bhasma ( calx ) has as its main indication , prameha ( diabetes ) . in the 14 century , rasaka satva ( the metallic extract of zinc carbonate / zinc oxide ) was also independently known by the name " yashada " . since then
, its bhasma has been in therapeutic use for various disorders including prameha ( diabetes ) , pandu ( anemia ) , vatavyadhis ( neuro - muscular diseases ) , and netra vikaras ( eye diseases ) .
yashada bhasma prepared using parada ( mercury ) is considered the best in rasashastra branch of ayurveda . however , in this competitive , commercialized world , the quality of a bhasma is always open to question . for bhasma quality assessment , various bhasma parikshas ( tests )
the namburi phased spot test ( npst ) , a spot test based on a chemical reaction , is a new technique for assessing the quality of a prepared bhasma .
when a drop of clear solution of a substance under examination ( bhasma or sindhura ) is put on specially prepared chemical reacting papers , a spot appears which manifests a series of colour and pattern changes . in chemistry ,
the npst involves observations of the spot and its colour , at three successive phases spread over three different time intervals .
it thus has the advantage of measuring sensitivity of reactions at different time intervals . in other words
, it constitutes a method to study or detect , every second or even fraction of a second , continual chemical reactions taking place gradually between two chemical substances on static media .
namburi hanumantha rao in 1970 , it has been accepted by ccras , new delhi .
npst and other classical tests were performed on samples of yashada bhasma : the first prepared classically using parada ; and three other market samples , also said to be parada marita , in order to compare and evaluate their quality .
a three - part methodology was used : 
 obtaining samples of yashada bhasma : first prepared classically , three others as market samples.subjecting all samples to classical bhasma parikshas.subjecting all samples to npst . 
  obtaining samples of yashada bhasma : first prepared classically , three others as market samples . subjecting all samples to classical bhasma parikshas . subjecting all samples to npst . authenticated raw yashada ( zinc metal )
was taken from the department of rasashastra , k. l. e. u. shri b. m. k. ayurveda mahavidyalaya , shahapur , belgaum , karnataka , and subjected to samanaya shodhana ( general purification ) by the dhalana ( liquefying and pouring ) method in tila ( sesamum indicum ) taila ( oil ) , takra ( butter milk ) , gomutra ( cow 's urine ) , kanjika ( sour gruel ) , kulattha ( dolichus biflorus ) , and kwatha ( decoction ) .
after samanya shodhana , vishesha shodhana ( specific purification ) was carried out by the ( same ) dhalana method in churnodaka ( lime water ) seven times .
after shodhana , the metal became more brittle , and was then subjected to jarana ( roasting ) using apamarga panchanga churna ( achyranthes aspera ) .
after jarana , the metal was converted into a very fine grey shining powder which was deemed fit for marana ( incineration ) .
the powder was then subjected to marana by triturating it with shuddha parada ( purified mercury ) , 1/4 of yashada and shuddha gandhaka ( purified sulphur ) , 1/4 of yashada , to form a black powder , to which one bhavana ( triturating in liquid media ) each with kumari swarasa ( fresh juice of aloe vera ) and nimbu swarasa ( fresh juice of citrus limon ) was given and chakrikas ( pellets ) prepared . after drying , they were kept in sharava ( casseroles ) ,
sandhi bandhana ( sealing ) was done and subjected to gajaputa with 1000 cow dung cakes .
the prepared yashada bhasma ( sample number 4 ) , and the three market samples ( numbers 1 , 2 and 3 ) were subjected to various classical bhasma parikshas like rekhapurnata , varitara , unama , nishchandrata , nirdhuma and niswadu [ table 1 ] .
analysis of four samples of yashada bhasma all the four samples were subjected to npst .
0.5 ml of 5n hno3 was thenadded to it drop by drop , and heated for one minute .
it was kept in a stand for 50 hours , during which time it was shaken occasionally .
it was then allowed to settle while a clear layer formed [ figure 1 ] .
one drop was taken from the clear layer and placed on 10% potassium iodide paper ( prepared using whatman 's filter paper no.1 ) , colour changes in the paper was observed over 3 time periods ref .
figure 2 : yashada bhasma samples npst of yashada samples 2 phase : 5 min to 20 min
authenticated raw yashada ( zinc metal ) was taken from the department of rasashastra , k. l. e. u. shri b. m. k. ayurveda mahavidyalaya , shahapur , belgaum , karnataka , and subjected to samanaya shodhana ( general purification ) by the dhalana ( liquefying and pouring ) method in tila ( sesamum indicum ) taila ( oil ) , takra ( butter milk ) , gomutra ( cow 's urine ) , kanjika ( sour gruel ) , kulattha ( dolichus biflorus ) , and kwatha ( decoction ) .
after samanya shodhana , vishesha shodhana ( specific purification ) was carried out by the ( same ) dhalana method in churnodaka ( lime water ) seven times .
after shodhana , the metal became more brittle , and was then subjected to jarana ( roasting ) using apamarga panchanga churna ( achyranthes aspera ) .
after jarana , the metal was converted into a very fine grey shining powder which was deemed fit for marana ( incineration ) .
the powder was then subjected to marana by triturating it with shuddha parada ( purified mercury ) , 1/4 of yashada and shuddha gandhaka ( purified sulphur ) , 1/4 of yashada , to form a black powder , to which one bhavana ( triturating in liquid media ) each with kumari swarasa ( fresh juice of aloe vera ) and nimbu swarasa ( fresh juice of citrus limon ) was given and chakrikas ( pellets ) prepared . after drying ,
they were kept in sharava ( casseroles ) , sandhi bandhana ( sealing ) was done and subjected to gajaputa with 1000 cow dung cakes .
the prepared yashada bhasma ( sample number 4 ) , and the three market samples ( numbers 1 , 2 and 3 ) were subjected to various classical bhasma parikshas like rekhapurnata , varitara , unama , nishchandrata , nirdhuma and niswadu [ table 1 ] .
0.5 ml of 5n hno3 was thenadded to it drop by drop , and heated for one minute .
it was kept in a stand for 50 hours , during which time it was shaken occasionally .
it was then allowed to settle while a clear layer formed [ figure 1 ] .
one drop was taken from the clear layer and placed on 10% potassium iodide paper ( prepared using whatman 's filter paper no.1 ) , colour changes in the paper was observed over 3 time periods ref .
figure 2 : yashada bhasma samples npst of yashada samples 2 phase : 5 min to 20 min
bhasma parikshan ( testing ) according to npst is given in table 2 npst of yashada bhasma
the colours of the four bhasmas all differ a great deal , varying from creamish to dark brown . the wide range of colour difference may be due to the amount of parada ( mercury ) and gandhaka ( sulphur ) added during marana ( incineration ) , and also on the number of puta given .
the touch of the bhasma showed that samples 3 and 4 are much finer than the other two samples . in sample 2 ,
though all samples passed the varitara test , samples 2 and 3 failed in the unama test , indicating the presence of untransformed metal in the bhasma .
the apunarbhava and niruttha tests were conducted only on sample 4 , which passed both tests , showing that chemically the bhasma was totally formed .
if these tests had been negative then it would have indicated the presence of a metallic part in the bhasma . in npst
the desired results were seen in all 4 samples , but sample 4 showed more accurate results compared to the others [ figure 2 ] .
the results seemed to be similar , but were not the same - an advantage of conducting npst over other classical bhasma parikshas .
the classical tests can not differentiate between bhasmas chemically , but in npst , as the test is chemical reaction - based , with specific results for specific bhasmas , we can differentiate between bhasmas clearly .
this technique is very helpful for quality assessment of bhasma as per the standards of rasashastra . in other words ,
bhasmas can be identified by their name given in rasashastra by virtue of their quality differences , but not chemically .
it is such a simple test that it can be carried out with minimum set up and requirements .
ccras has also accepted the monograph of npst , and so the quality of bhasma can be checked before being used therapeutically . in the present study , though the bhasma was said to be prepared by same method , there was lot of difference in bhasma colour , and according to npst only sample 4 , prepared in our department , gave results in accordance with the text .
yashada bhasma ( calx of yashada i.e. zinc ) which has its main indication in prameha ( diabetes ) and netra vikaras ( eye disorders ) was prepared according to the prescription in the ayurvedic classics and subjected to various bhasma parikshas , including the namburi phased spot test ( npst ) , one of the qualitative tests described for various ayurvedic preparations . 
 npst helps differentiate between , and thus identify , various bhasmas . 
 it depends upon the pattern of the spot , which develops after a specific chemical reaction . 
 three market samples of yashada bhasma , which were said to be parada marita ( incinerated using mercury ) , were also subjected to the above tests and results compared . 
 the various bhasmas exhibited marked differences in colour , and though npst yielded desired results for all the samples , there were differences in their spot patterns and colour . 
 the bhasma prepared in our department produced the most accurate results .