razepam. The sample may be a liquid and more specifically a beverage of some type. As shown in the examples set forth below, the present invention is effective where beverages contain ethanol as well as other constituents that traditionally make up drinks served on a social basis. In addition to detecting flunitrazepam, the present invention may be useful in the detection of nitrazepam and clonazepam, structurally-similar benzodiazepines bearing a nitro group at the 7-position.
A suitable reducing agent may be any active metal or other reducing agent known in the art to be capable of reducing the nitro group of flunitrazepam to a reduced species. Suitable active metals include zinc, tin, magnesium, iron, cobalt, copper, bismuth, lead or indium. This list is meant to be illustrative and other active metals may be suitable for use with the invention. The preferred reducing agent of the present invention is tin (II) chloride. Alternatively, reducing agents such as alkaline sodium hydrosulfite (sodium dithionite), sodium borohydride, or ammoniacal ferrous sulfate may be utilized with the present invention. Other reducing agents not specifically set forth here capable of effectively reducing flunitrazepam may also be useful in the present method. However, not all reducing agents are suitable with the method as sodium sulfite and sodium thiosulfate have been identified as not suitable for use with the invention.
The reducing agent and hydrolyzing agent are provided in the invention at concentrations to effectively reduce and hydrolyze flunitrazepam in the sample to the reduced and hydrolyzed species in an amount sufficient to provide a concentration of reduced and hydrolyzed species capable of being colorimetrically detected following Schiff base formation with a visualizing agent. For tin (II) chloride, the concentration to provide this effective reduction may be as low as 0.75% with 2.5% being the preferred final concentration (xe2x80x9cfinal concentrationxe2x80x9d, unless specifically noted otherwise, is defined herein as the concentration prior to addition of the visualizing agent).
Zinc may also be used as a reducing agent with the present invention and provides an effective reduction of flunitrazepam for use in combination with the visualizing agents disclosed below. Zinc final concentration (prior to addition of the visualizing agent) may be as low as 0.04% with 0.4% being the preferred concentration of zinc necessary
razepam. The sample may be a liquid and more specifically a beverage of some type. As shown in the examples specify away below, the present invention is effective where beverages control ethyl alcohol as well as other constituents that traditionally induce up drinks served on a social basis. In addition to detecting flunitrazepam, the present invention may be utilitarian in the detection of nitrazepam and clonazepam, structurally - similar benzodiazepines bearing a nitro group at the 7 - stead. 
 A suitable reducing agent may be any active metal or other reduce agent known in the artwork to be capable of reducing the nitro group of flunitrazepam to a decreased species. desirable active metals include zinc, tin, magnesium, iron, cobalt, copper, bismuth, lead or indium. This list is meant to be exemplifying and other active metals may be suitable for use with the invention. The preferred reducing agent of the present invention is tin (II) chloride. Alternatively, reducing agents such as alkaline sodium hydrosulfite (sodium dithionite), sodium borohydride, or ammoniacal ferrous sulfate may be utilized with the present invention. Other reducing agents not specifically set forth here capable of efficaciously reduce flunitrazepam may also be utilitarian in the present method acting. However, not all reducing agents are suitable with the method as sodium sulfite and sodium thiosulfate have been name as not desirable for use with the invention. 
 The reducing agent and hydrolyze agent are provided in the invention at concentrations to effectively reduce and hydrolyze flunitrazepam in the sample to the decreased and hydrolyzed species in an amount sufficient to provide a concentration of reduced and hydrolyzed species capable of being colorimetrically detect follow Schiff base formation with a visualizing agentive role. For tin (II) chloride, the concentration to provide this effective reduction may be as low as 0.75% with 2.5% being the preferred final concentration (xe2x80x9cfinal concentrationxe2x80x9d, unless specifically note otherwise, is define herein as the concentration prior to accession of the visualizing agentive role). 
 Zinc may also be used as a reducing agent with the present invention and provide an effective reduction of flunitrazepam for use in combination with the visualize agents disclose below. Zinc final concentration (prior to addition of the visualizing agent) may be as low as 0.04% with 0.4% being the preferred assiduity of zinc necessary
razfpam. The sample may be a liquid and morg wpecifmcally z beveraee of some type. As shown in vhe wxampoes set forth below, thd present inventiin iw effective where bcreragsd coutein ethanol as eell as otver constituends tkat traditionally make up drinks serded on s docial basis. Ig adcytioh to detecting flunitrazepam, the pdesent pnvention may be iseful in the detection of nitgazepam and clonazfpam, structodaljt-similar benxodiazepints bearing a nitro group at the 7-position.
A sjitabke reducint qgejj may be any actine metal or obner regucing sgent known in thx arr to be capable of revucing the nitro groop of flunhtxazepam to a reduced wpwcies. Suidabld acgivt mxtams incpudx zinc, tin, jagnesium, ieon, cobalt, copper, bosilyh, lead or ihdium. Ehys list is meant to be illustrative and otger active metals may bw suitable for use wijh the invqntion. The preferred reducing agent of the presend invxngiou is tkb (LI) chloride. Alternatively, reducing agents sucr ax slkaline sodiui hydrosulfotf (xjdium dithionkte), sobjuj borohydride, or almoniacwl feerous sulsate may be utilized with the peesent invennion. Other reducing agznts not speeificakly srt forth here capable oy effedtively redkcing fluhktrazepam may alro ne gseful in the present methjd. Howevec, not all reaucimg agegts are sultablc with the method ad sodnum sglfite and sodium thiosulfate have been ivxntified as npt suptable fox use eith the invegtion.
The reducnng agenc and fydrolyzinf agent are providqd in the invajtion at conrentratiogs ti efdectiveuh reduce and hudrolyze yjunirrazepam in the sakplg fo the reduced cud hydrolyzed spevier ig wn aimunt sufficiant go otovidd a concentvatkon pf reduced and hydronyzes species capable pf being cilorimetwically detecyed following Schivf bave hormatoon with a visualizing agent. For fin (II) chporlde, the concegtrabion to providz this effective reduction may be as low as 0.75% with 2.5% being jhe preferred final cpkcentration (ee2x80x9cfynal concantrationxe2x80x9d, unlesw specifically noued otherwise, is defines herehn as the concentration prior to addition of the visualizing agent).
Zinc may alsi be used as a redhcinb agett cith thq prxsxnt invention and provides an effective reductioi of flunidrczepam for use in combination wkth the visuauizing agents disclosed gelow. Zimc final concentration (prior to addition of the visualiding agenr) may be as low as 0.04% with 0.4% being tne preyerred concenrratlon of zinc nezesxavy
razepam. The sample may be a liquid specifically beverage of type. As shown below, present invention is where beverages contain as well as other constituents that make up drinks served on a social basis. In addition to detecting flunitrazepam, present invention may be useful in the detection of nitrazepam and clonazepam, structurally-similar bearing nitro at 7-position. A suitable reducing agent may be any active metal or other reducing agent known in art to be capable of reducing the nitro of flunitrazepam to a species. Suitable active metals include tin, iron, cobalt, bismuth, or This list is to be illustrative and other active metals may be suitable for use with the invention. The preferred agent of invention is (II) Alternatively, agents such as hydrosulfite (sodium dithionite), sodium borohydride, or may be utilized with the present invention. Other agents not set forth here capable of effectively flunitrazepam may also be useful in the present However, not all reducing agents are suitable with the method as sodium sulfite and sodium been identified as not for use with invention. reducing and agent are in the invention at concentrations to effectively reduce and hydrolyze flunitrazepam the sample to the reduced and hydrolyzed species in an to a concentration of and hydrolyzed species capable being detected following Schiff base a agent. chloride, concentration provide this effective reduction be as low as 0.75% 2.5% being the preferred specifically noted otherwise, is defined herein as the prior to addition of the visualizing agent). may also be used as a reducing agent with the present invention provides an of flunitrazepam for use in combination with the agents disclosed below. Zinc concentration (prior to addition of the visualizing agent) may as as 0.04% 0.4% being the concentration of zinc
razepam. The sample may be a liqUid and more SpeciFicAllY a BeveRage Of some type. As shOWn in The examples set forth belOw, the PrESent INvEntioN is effeCTiVE WheRe BeVerAgES cOntaiN etHanol as Well as otheR coNsTituents that TRaDitionally MakE up drinks serVed On a socIaL baSIs. In aDdiTion tO detecTIng fluNitrazepaM, tHE preseNT inventION mAy be Useful in the detectIOn OF nitrazepam and ClonazEpAM, sTRUctUraLly-similar BeNzodiAZepines BEaRING a nITro group at the 7-Position.
A suITabLe reduCiNg aGEnt may Be any AcTIve Metal or otheR redUcing agenT known IN the art TO be capaBle of rEduCinG the NItRo GroUp OF flUNiTraZEpaM to a reduCeD sPecieS. SuiTABLE actIve MetaLs incLude zinc, tin, maGneSium, IRon, CobalT, coppEr, biSmUth, leAd or inDium. THiS list is meant to bE illUstrative And OtHer AcTive mETals maY be SuiTable foR use witH The InVENTiOn. The preferred reduCiNG AgEnt of the PresenT InVeNTion is tiN (Ii) chLoriDE. alterNatiVElY, reducinG agentS SuCh As alkalInE sodiuM hYdrOsuLfite (SOdiuM dithiOnite), sodIum boROhydride, or ammoNIacal ferrous sULfATE mAY be uTilIzed with the PresENt inVentIOn. othER reduCing aGeNTs NOt specifically set foRtH here cApablE of effectivelY reducing fLUNItrazepaM may ALsO Be useful in the pResenT method. HowEVer, not alL reduCing agenTs are suitABLe with thE meThoD as SodIUM sUlfite and sodiUM ThioSuLfate haVe bEen idenTifIed As nOt sUiTable for uSe with thE iNvEnTiOn.
THe redUCing agenT aNd hYdRolYzing AGent arE provIded In ThE InvEntion aT CoNCEntrAtIoNs to EffEcTivelY redUCe aNd hydroLyze fluniTraZEpam In ThE sample To the reduced aNd Hydrolyzed SpEciEs in an AMOunt suffIcient to provide a concentRAtion of RedUced aNd hyDrolyzed sPecIes capAblE Of beinG colorImetrIcAllY DEtectED FoLloWiNg Schiff baSE ForMatioN wIth a VisualiZing agent. For tin (II) cHLorIde, the concentRatIon tO PRoVidE ThIS efFeCTivE REduction may be as Low as 0.75% with 2.5% bEiNG tHe preferreD FinAl ConcentRation (xE2x80x9cfINal concEntrationXe2x80x9d, unleSs SpecIFIcaLly noted otHerwise, iS defined hERein aS ThE concEntRation PrIor To addItion oF The VisuaLizing AgEnt).
ZinC may aLsO be used aS a reducing agent with the pResent InvenTioN and proviDes AN efFective reDuctIon of fluniTraZepAm for Use IN combInatIOn WitH The viSualIZing agentS DiSclOSEd Below. Zinc fiNAL ConCentrAtiON (prior To adDition of the visualIZing agent) may be As loW AS 0.04% wiTh 0.4% bEIng tHe Preferred conceNtrAtION of zinc nEcEssary
razepam. The sample may be  a liquidand m ore  sp ec ific ally  a beverage of some  type. As shown in the  exam pl e s se t  f orthbelow,t he p res en tinv en t io n iseff ectivewhere beve rag es  contain eth a no l as wellasother consti tue nts th at  tr a ditio nal ly ma ke upd rinksserved on  a social basis.I n  a ddit ion to detectingf lu n itrazepam, the  prese nt in v e nti onmay be use fu l int he dete c ti o n ofn itrazepam and  clonazepam ,  st ructur al ly- s imilar  benz od i aze pines beari ng a  nitro gr oup at the 7-p o sition. 
A sui tab leredu c in gage nt may be  an y  ac tive met al  o r oth er r e d u c ingage nt k nownin the art to  be  cap a ble  of r educi ng t he  nitr o grou p offl unitrazepam toa re duced spe cie s.  Su it ablea ctivemet als  includ e zinc, tin ,m a g ne sium, iron, cobalt ,c o pp er, bism uth, l e ad  o r  indium.  T his  lis t is me antt obe illus trativ e  a nd  otherac tive m et als  ma y bes uita ble fo r use wi th th e  invention. Th e  preferred re d uc i n ga gent  of  the presen t in v enti on i s  t in( II) c hlori de .  A l ternatively, reduci ng  agent s suc h as alkaline  sodium hy d r o sulfite(sod i um dithionite), s odium  borohydri d e, or am monia cal ferr ous sulfa t e  may beuti liz edwit h th e present inv e n tion .Other r edu cing ag ent s n otspe ci fically s et forth  h er eca pab le of effectiv el y r ed uci ng fl u nitraz epammayal so beusefuli nt h e pr es en t me tho d.  Howe ver, not  all re ducing ag ent s  are  s ui table w ith the metho das sodiumsu lfi te and s odium th iosulfate have been ide n tifiedasnot s uita ble for u sewith t hei nventi on.
Th e red uc ing a genta n dhyd ro lyzing age n t  ar e pro vi dedin theinvention at conce n tra tions to effe cti vely r ed uce an d  hy dr o lyz e flunitrazepam i n the samp le to  the reduc e d a nd  hydrol yzed sp ecies in an a mount suf ficient t oprov i d e a  concentra tion ofreduced a n d hyd r ol yzedspe cies c ap abl e ofbeingc olo rimet ricall ydetect ed fo ll owing Sc hiff base formation wit h a vi suali zin g agent.For tin  (II) chl orid e, the con cen tra tiontop rovid e th i seff e ctive  red u ction may be  as l ow  as 0.75% w i t h  2. 5% be ing the pr efer red final concent r ation (xe2x80x 9cfi n a l c onc e ntra ti onxe2x80x9d, u nle ss s pecifica ll y noted oth erwise,is defin ed her ein as  the co n c en t ration  pri orto additi onof the vis ua li z ing ag ent) .Zinc m ay als o  beu s ed as a reducing  agen t witht heprese nt  invent i on a nd provide s an effect ive re duct ion o f fluni tr azepam  fo ruse in com b ination w ith t he visu al izin g a gentsdisc l o sed b elow .Zin c final c o n ce n tr at i on(pri or to  a ddit ion of th e  visuali zin g  agent)  m ayb e  as lo w  a s 0.04% with  0. 4% be i n g the pref e rred co n centr ationof zin c neces s ary 
razepam. The_sample may_be a liquid and_more specifically_a_beverage of_some_type. As shown_in the examples_set forth below, the_present invention is_effective_where beverages contain ethanol as well as other constituents that traditionally make up drinks_served_on a_social_basis._In addition to detecting flunitrazepam,_the present invention may be_useful in_the detection of nitrazepam and clonazepam, structurally-similar benzodiazepines_bearing_a nitro group_at the 7-position.
A suitable reducing agent may be any_active metal or other reducing agent_known in the_art_to_be capable of reducing_the nitro group of flunitrazepam to_a reduced species. Suitable active metals_include zinc, tin, magnesium, iron, cobalt, copper,_bismuth, lead or indium. This list_is meant to be illustrative_and other_active metals may be suitable_for use with_the invention._The preferred reducing_agent of the present invention is_tin (II) chloride._Alternatively, reducing agents such as alkaline_sodium_hydrosulfite (sodium dithionite),_sodium_borohydride,_or ammoniacal_ferrous sulfate may_be_utilized with_the_present invention. Other reducing agents not_specifically_set forth here capable of effectively reducing_flunitrazepam may also be_useful_in the present method._However, not all reducing agents_are suitable with the method as_sodium sulfite_and sodium_thiosulfate have been identified as not suitable for use with the_invention.
The reducing agent and hydrolyzing agent_are provided in the_invention at_concentrations_to effectively reduce_and_hydrolyze flunitrazepam_in the sample to the reduced and_hydrolyzed species_in an amount sufficient to provide_a concentration of reduced_and_hydrolyzed species capable of being colorimetrically_detected following Schiff base formation with_a visualizing agent. For tin_(II)_chloride,_the concentration to provide this_effective reduction may be as low_as 0.75% with_2.5% being the preferred final concentration (xe2x80x9cfinal_concentrationxe2x80x9d,_unless specifically noted otherwise, is defined_herein_as the concentration prior to addition_of_the_visualizing agent).
Zinc may also be_used as a reducing agent with_the present invention and provides an effective reduction of_flunitrazepam for use_in combination with the visualizing_agents_disclosed_below. Zinc final concentration (prior to addition of the visualizing_agent) may_be as low_as 0.04% with 0.4% being the preferred concentration of zinc_necessary