Ima­gi­ne, Snif­fing Mole­cu­les

Ima­gi­ne a de­vice that could ana­ly­ze the mole­cu­lar com­pon­ents of a sam­ple by „snif­fing“ them. This me­thod is known as „Di­rect Scree­ning“ and gai­ned pro­mi­nence, espe­ci­al­ly in the mid-2000s, when it be­ca­me pos­si­ble in com­bi­na­ti­on with high­ly sen­si­ti­ve mass spec­tro­me­ters (= Di­rect MS). Read in this ar­tic­le, what Di­rect MS me­ans for re­se­arch and ana­ly­sis la­bo­ra­to­ries, the po­ten­ti­al of this new me­thod, and the chal­lenges that still exist af­ter ne­ar­ly twen­ty ye­ars of de­ve­lo­p­ment.

Let’s Start from the Be­gin­ning: Snif­fing Mole­cu­les?

For a mole­cu­lar ana­ly­sis, the sam­ple is ty­pi­cal­ly pre­pared in the la­bo­ra­to­ry and then se­pa­ra­ted into its in­di­vi­du­al com­pon­ents using a chro­ma­to­graph. Sub­se­quent­ly, the­se com­pon­ents are io­ni­zed th­rough an ion source, or „char­ged,“ al­lo­wing them to be „weig­hed“ in a mass spec­tro­me­ter (MS), with their re­spec­ti­ve mass at­tri­bu­ted to a spe­ci­fic mole­cu­le.

Usual­ly, such an ana­ly­sis re­qui­res a chro­ma­to­graph for li­quid (LC) or gas­eous sub­s­tances (GC), an ion source, and a mass spec­tro­me­ter (LC-MS or GC-MS). With Di­rect MS, the la­bor-in­ten­si­ve sam­ple pre­pa­ra­ti­on in the lab and se­pa­ra­ti­on using chro­ma­to­gra­phy are by­pas­sed. In­s­tead, the sam­ple is sim­ply held di­rect­ly in front of the in­let of a mass spec­tro­me­ter. The sam­ple can thus be „snif­fed“ at at­mo­sphe­ric pres­su­re.

A Who­le Uni­ver­se of New Pos­si­bi­li­ties

This not only sa­ves a tre­men­dous amount of time and per­son­nel but also un­veils a uni­ver­se of new ap­pli­ca­ti­ons. Con­sider, for in­s­tance, con­tai­ner safe­ty, drug de­tec­tion, ex­plo­si­ve checks, food in­spec­tions, or me­di­cal ap­pli­ca­ti­ons such as breath ana­ly­ses or the iden­ti­fi­ca­ti­on of in­fec­tions for tar­ge­ted an­ti­bio­tic ad­mi­nis­tra­ti­on. In con­ven­tio­nal me­di­cal ana­ly­tics, swabs or blood samples must curr­ent­ly be ta­ken, pro­ces­sed ex­ten­si­ve­ly, and then ana­ly­zed. Di­rect MS en­ables the real-time iden­ti­fi­ca­ti­on of di­se­a­ses. Ho­we­ver, if it were as straight­for­ward as it sounds, you would have pro­ba­b­ly he­ard of it by now. Be­cau­se what sounds so pro­mi­sing in theo­ry also co­mes with its fair share of chal­lenges.

Still Work to Do

Most mass spec­tro­me­ters are bul­ky and high­ly sen­si­ti­ve, which curr­ent­ly makes them un­sui­ta­ble for field use. The stan­dard me­thod known in the 2000s using the Di­rect Ana­ly­sis in Real Time (DART) ion source has the di­s­ad­van­ta­ge of of­ten be­ing ope­ra­ted with he­li­um, re­qui­ring the lo­gi­stics and hand­ling of a gas cy­lin­der in ad­di­ti­on to the MS. Not to men­ti­on the cos­ts and avai­la­bi­li­ty of this no­ble gas (read also: He­li­um Shorta­ge: Hy­dro­gen as an Al­ter­na­ti­ve Car­ri­er Gas with Be­ne­fits on Top) Quan­ti­fy­ing sub­s­tances also pres­ents cur­rent dif­fi­cul­ties, and hand­ling vo­la­ti­le, gas­eous samples is ne­ar­ly im­pos­si­ble with this me­thod.

What is nee­ded is a por­ta­ble and ro­bust MS and a ver­sa­ti­le ion source that pro­vi­des quan­ti­fia­ble data for so­lid, li­quid, and gas­eous sub­s­tances. SICRIT® and Ha­Voc® ad­dress the­se chal­lenges for Di­rect MS.

Re­a­dy to Sniff

The ca­pa­bi­li­ty of SICRIT® has al­re­a­dy been pro­ven in va­rious use ca­ses in App No­tes and Pa­pers on Di­rect MS. Now, it’s only a mat­ter of ex­pan­ding the uni­ver­se of ap­pli­ca­ti­on pos­si­bi­li­ties and es­tab­li­shing Di­rect MS in la­bo­ra­to­ries and field ope­ra­ti­ons. This could save la­bo­ra­to­ries an im­mense amount of time, set a new stan­dard for food safe­ty, and sim­pli­fy and ex­pe­di­te me­di­cal dia­gno­stics si­gni­fi­cant­ly.

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