Tiêu chuẩn iso ts 19590 2017

This document was develo ed in r sp nse t o the worldwide deman of suita le methods for the det ection an charact erization of nano articles in fo d an consume prod ct.. Single p rticle

Nanotechnolog ies — Size distribution

Na ote h olo ie s - Distribution de taille et co c ntration de

n n p rtic ule s inorg nique s en milieu a ueu p r spec trométrie de

masse à plasma induit en mode p rticule u ique

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F reword i v

Introduction v

1 Sc ope 1

2 Nor mati ve r eferenc es 1

3 Terms an definitions 1

4 A bbreviated terms 2

5 Co for manc e 2

6 Proc ed re .3

6.1 Principle

3 6.2 A pp r atus an eq ipment 3

6.3 Chemicals, r eferenc mate ials and r eag ent 3

6.3.1 Chemicals 3

6.3.2 Refer enc mate ials 3

6.3.3 Reag ents 4

6.4 Samples 4

6.4.1 A mou t of sample 4

6.4.2 Sample diution 5

6.5 Ins rumental set ing san pe formanc che k 5

6.5.1 S ting s of the ICP-MS sys em 5

6.5.2 Che king the pe formanc of the ICP-MS sys em 5

6.6 Dete mination of the transp rt eficiency 6

6.6.1 Dete mination of transport eficiency b sed on measur ed particle fr eq ency 6

6.6.2 Dete mination of transport eficiency b sed on measur ed particle siz 7

6.7 Dete mination of the lnearity of r esp nse 8

6.8 Dete mination of the blank level 8

6.9 A nalysis of aq eous suspension 8

6.1 Data conve sion 9

7 Results 9

7.1 Calculations 9

7.1.1 C lculation of thetransp rt eficiency 1

7.1.2 C lculation of theICP-MSr esp nse 1

7.1.3 C lculation of p rticle conc ntration an siz 1

7.1.4 C lculation of thep rticle conc ntr ation dete tion lmit 1

7.1.5 C lculation of thep rticle siz dete tion lmit 1

7.1.6 C lculation of ionic conc ntr ation 1

7.2 Pe formanc c ite ia 1

7.2.1 Transp rt eficiency 1

7.2.2 Linearity of the calbration curve 1

7.2.3 Blan samples 1

7.2.4 Numbe of dete ted p rticles 1

8 Test rep r t 13

A nne x A (informative)Calculation spr eadshe t 15

Biblog raphy 19

ISO (he Int ernational Org nization for Stan ardization) is a worldwidefede ation of national s an ards

b dies (ISO membe b dies) The work of pr p ring Int ernational Stan ards is normaly car ied out

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org nizations, g ove nmental an non-g ove nmental, in laison with ISO, also take part in the work

ISO cola orat es closely with the Int ernational Ele trot ech ical C mmis ion (IEC) on al matt ers of

ele trot ech ical s an ardization

The proc d r s used t o develo this document an those int en ed for it furthe maint enanc ar

desc ibed in the ISO/IEC Dir ctives, Part 1 In p rticular the dife ent a pro al c it eria ne ded for the

dife ent ty es of ISO document should be not ed This document was draft ed in ac ordanc with the

edit orial rules of the ISO/IEC Dir ctives, Part 2 ( e www iso org dir ctives)

A tt ention is drawn t o the p s ibi ity that some of the element of this document ma be the subje t of

p t ent right ISO shal not be held r sponsible for identifying any or al such p t ent right Detais of

any p t ent right identified d ring the develo ment of the document wi be in the Introd ction an / r

on the ISO ls of p t ent de larations r c ived ( e www iso org p t ent )

Any trade name used in this document is information given for the convenienc of use s an does not

cons itut e an en orsement

F or an ex lanation on the v lu tary natur of s an ards, the meaning of ISO spe if ic t erms an

ex r s ions r lat ed t o conformity as es ment, as wel as information a out ISO’ s adhe enc t o the

World Trade Org nization (WTO) principles in the Te hnical Bar ie s t o Trade (TBT) se the folowing

URL: www iso org iso / for word html

This document was pr p r d b ISO/TC 2 9, Na otechn lo ies

This document was develo ed in r sp nse t o the worldwide deman of suita le methods for the

det ection an charact erization of nano articles in fo d an consume prod ct Prod ct b sed on

nanot echnolo y or containing engine r d nano articles ar alr ady in use an beginning t o imp ct

the fo d-as ociat ed in us ries an market As a conseq enc , dir ct an indir ct consume ex osur

t o engine r d nano articles ( in ad ition t o natural nano articles) be omes mor l kely The det ection

of engine r d nano articles in fo d, in samples from t oxicolo y an in ex osur s u ies the efor

be omes an es ential p rt in un e s an ing the p t ential benef it , as wel as the p t ential risks, of the

a plcation of nano articles

Single p rticle ind ctively coupled plasma mas spe trometry ( pICP-MS) is a method ca a le

of det ecting single nano articles at ve y low conc ntrations The aq eous sample is introd c d

contin ously int o a s an ard ICP-MS sy st em that is set t o acq ir data with a high time r solution ( i.e a

short dwel time) F olowing nebulzation, a fraction of the nano articles ent ers the plasma w he e they

ar at omiz d an the in ivid al at oms ioniz d F or every particle at omiz d, a clou of ions r sult This

clou of ions is sampled b the mas spe tromet er an sinc the ion density in this clou is high, the

signal pulse is high comp r d t o the b ckgrou d (or b sel ne) signal if a high time r solution is used

A ty ical ru time is 3 s t o 2 0 s an is caled a “ ime scan.” The mas spe tromet er can be tu ed t o

measur any spe if ic element, but d e t o the high time r solution, ty icaly only one m/ z v lue wi l be

monit or d d ring a run (with the cur ent ins rument )

The n mbe of pulses det ect ed pe se on is dir ctly pro ortional t o the n mbe of nano articles in

the aq eous suspension that is being measur d To calculat e conc ntrations, the transp rt efficiency

has t o bedet ermined firs using a r fe enc nano article The int ensity of the pulse and the pulse ar a

ar dir ctly pro ortional t o the mas of the measur d element in a nano article, an the eb t o the

nano article’ s diamet er t o the third powe ( i.e as uming a sphe ical g eometry for the nano article)

This means that or any inc ease of a p rticle’ s diamet er, the r sp nse wi inc ease t o the third powe

an the efor a pro e v ldation of the r sponse for each siz rang e of each comp sition of nano article

is r q ir d Calbration is bes pe formed using a r fe enc nano article mat erial; howeve , such

mat erials ar oft en not a aia le The efor , calbration in this proc d r is pe formed using ionic

s an ard solutions of the measur d element un e the same analytical con ition

The data can be proc s ed b comme cialy a ai a le sof war or it can be import ed in a cust om

spr adshe t pro ram t o calculat e the n mbe an mas conc ntration, the siz ( he sphe ical eq iv lent

diamet er)an the cor esp nding n mber-b sed siz dis ribution of the nano articles In ad ition, mas

conc ntrations of ions pr sent in the same samplecan be det ermined from the same data

The int er st ed r ade can consult R efe enc s [1]t o [4] for furthe information

Nanotechnolog ies — Size distribution and c onc entration

This document spe if ies a method for the det ection of nano articles in aq eous suspensions an

charact erization of the p rticle n mbe an particle mas conc ntration an the n mber-b sed siz

dis ribution using ICP-MS in a time-r solved mode t o det ermine the mas of in ivid al nano articles

an ionic conc ntrations

The method is a plca le for the det ermination of the siz of inorg nic nano articles (e.g metal an

metal o ides lke A u, Ag, TiO

2, BVO

4, et c ), with siz rang es of 1 nm t o 1 0 nm (an larg er p rticles up t o

1 0 0 nm t o 2 0 0nm) in aq eous suspensions Metal compoun s othe than o ides (e.g sulf ides, et c ),

metal comp sit es or co t ed p rticles with a metal cor can be det ermined if the chemical composition

an density ar k own Particle n mbe conc ntrationsthat can be det ermined in aq eous suspensions

rang e from 1

6

p rticles /L t o 1

9

particles /L w hich cor esp n s t o mas conc ntrations in the rang e

of a pro imat ely 1 ng L t o 1 0 0 ng L (for 6 nm A u p rticles) A ctual n mbe s depen on the ty e of

mas spe tromet er used an the ty e of nano articleanaly sed

In ad ition t o the p rticle conc ntrations, ionic conc ntrations in thesuspension can also be det ermined

Limit ofdet ection ar compara le with s an ard ICP-MS measur ment Not e that nano articles with

siz s smal e than the p rticle siz det ection lmit of the spICP-MS method ma be q antified as ionic

The method pro osed in this document is not a pl ca le for the det ection an charact erization of

org nic or carbon-b sed nano articles lke enca sulat es, fule enes an carb n nanotubes (CNT) In

ad ition, it is not a pl ca lefor element othe than carb n an that ar diff icult t o det ermine with

ICP-MS R efe enc [5] gives an o e view of element that can be det ect ed an the minimum p rticle siz s

that can be det ermined with spICP-MS

2 Normati ve r eferences

The folowing document ar r fe r d t o in the t ext in such a wa that some or al of their cont ent

cons itut es r q ir ment of this document F or dat ed r fe enc s, only the edition cit ed a ples F or

un at ed r fe enc s, the lat es edition of the r fe enc d document ( inclu ing any amen ment ) a ples

ISO/TS 8 0 4-1, Na otechn lo ies — Voc ab lar y — Part 1: Cor te ms

3 Terms and definitions

F r the purp ses of this document, the te ms an def initions given in ISO/TS 8 004-1 and the

folowing a ply

ISO an IEC maintain t erminolo ical data ases for use in s an ardization at the folowing ad r s es:

— IECEle tro edia: a aia le at ht p:/ www ele tro edia org

— ISO Onlne brow sing plat orm:a ai a le at ht p:/ www iso org o p

3.1

nanoparticle

nano-o je t with al thr eext ernal dimensions in the nanoscale

[ SOURCE:ISO/TS8 0 4- 2:2 1 , modified]

analytical t ech iq e comprising a sample introd ction sy st em, an in uctively coupled plasma sour e

for ionization of the analyt es, a plasma v cu m int erfac an a mas spe tromet er comprising an ion

focusing, separation and det ection sy st em

3.4

dwel time

time d ring w hich the ICP-MS det ect or cole t an int egrat espulses

Not e 1 t o entry: F olowing inte ration, the total cou t n mb r per dwel time is re ist ered as one data point,

e pres ed in cou ts, or cou ts per secon

3.5

transp rt ef iciency

particle transport ef iciency

neb lzatio ef iciency

ratio of the n mbe of p rticles or mas of solution ent ering the plasma t o the n mbe of p rticles or

mas of solution aspirat ed t o the nebulz r

3.6

particle number concentration

n mbe of p rticlesdivided b the volume of a suspension, e.g particles /L

3.7

particle mas co centratio

t otal mas of the p rticles divided b the v lume of a sample, e.g ng L

3.8

number-based particle size distrib tio

l s of v lues that defines the r lative amount b n mbe s of p rticles pr sent ac ording t o siz

4 A bbreviated terms

spICP-MS single p rticle in uctively coupled plasma mas spe trometry (for the def inition of

ICP-MS, se 3.3 or ISO/TS 80 04-6:2 1 , 4.2 )

This method is r s rict ed t o aq eous suspensions of pur nano articles, aq eous extract of mat erials

or consume prod ct , aq eous dig es s of fo d or tis ue samples, aq eous t oxicolo ical samples or

environmental wat er samples The a plca i ty of the method for such samples should be ev luat ed b

the use Information a out sample proc s ing of non-aq eous samples can be fou d in the l t eratur

A queous environmental samples ar f iltrat ed an diut ed

[6]

fo d an t oxicolo ical samples ar

chemicaly or enzymaticaly dig est ed an diut ed

[7][8]

Howeve , t o r lat e p rticle n mbe or mas

conc ntrations in aq eous suspensions t o the conc ntrations in the original sample information on

extraction, eff iciency and matrix efe t ar r q ir d Ad itional v ldation b the use is r q ir d

6 Procedure

6.1 Principle

When nano articles ar introd c d int o an ICP-MS sy st em, they prod c a plume of analyt e ions

The plumes cor esp nding t o in ivid al nano articles can be det ect ed as a signal spike in the mas

spe tromet er if a high time r solution is used Using dwel times of ≤ 0 ms and an a pro riat e diution

of the nano article suspension alowsthe det ection of in ivid al nano articles, henc the name “ ingle

p rticle”ICP-MS Diution is oft en r q ir d t o a oid violation of the “ ingle particle rule”( i.e mor than

one p rticle ar iving at the det ect or in one dwel time) As an ex mple, using a dwel time of 3 ms, a

ma imum of 2 0 0 p rticles can be r gist er d pe min t e Howeve , t o satis y the “ ingle p rticle

rule” , the n mbe of pulses in the time scan should not ex ce d ca 1 2 0 pe min t e

[9]

(as a guidanc ,

a suspension of 60 nm g old p rticles with a mas conc ntration of 2 0 ng L at an ICP-MS input flow of

0,5 mL/ min an a transp rt efficiency of 3% wi r sult in this n mbe of pulses)

6.2 A pparatus and equipment

6.2.1 Inducti vel y c ou led plasma mas spectrometer, ca a le of han lng dwel times ≤ 0ms

6.2.2 Vor te x mixer

6.2.3 A nal ytical balanc e, ca a le of weighing to the near es 1 mg

6.2.4 Ultrasonic bath

6.2.5 Standard laborator y glas ware

6.3 Chemicals, r eferenc e materials and reag ents

6.3.1 C emicals

6.3.1.1 So ium d decyl sulfate (SDS);C

1H

2NaO

4

6.3.1.2 So ium citrate;C

6H

5

Na

3O

7

·2H

2O

6.3.1.3 Nitr ic acid, 7 %

6.3.1.4 Purified water , typicaly, wate with a > 8MΩ∙cm r esis ivity and < μg /L of dis olved salt

6.3.1.5 Rinsing fluid for the ICP-MS samplng system, consisting of 3 % nitric acid pr ep r ed b

di uting 40 mL of conc ntrated nitric acid (6.3.1.3) to 7 0 mL purified wate in a 1 L plas ic containe

6.3.2 Referenc e mater ials

6.3.2.1 F r the dete mination of the transp rt eficiency, a nano article r eferenc mate ial is

used, for example a suspension of g old nano articles, nominal p rticle siz 6 nm, with a nominal

mas conc ntration of 5 mg /L s a i z d in a citr ate bufe A s an alte native, a suspension of sive

nano articles, nominal p rticle siz 6 nm s a i z d in a citrate bufe can be used pr ovided the mate ials

ar e suficien y homog eneous an s a le

[1 ]

Sinc the nano article refer enc mate ials ar e used only to

dete mine the tr ansp rt eficiency, ha ving the same chemical comp sition as the nano article analyte is

not r eq ir ed

6.3.2.2 F r the siz dete mination sing le element , ionic s an ard solutions ar e used, namely c rtified

refer enc mate ials inten ed for use as a primary calbr ation s an ard for the q antitative dete mination

of an element

6.3.3 Re g ents

6.3.3.1 Stock stan ar d of nominal 6 nm g old nano articles (50 µg /L) Pipet 5 µL of the g old

nano articles(6.3.2.1) to 2 mL purified wate in a calbr ated 5 mL g las measuring flask an fi to the

mar k with purified wate , r esulting in a final mas conc ntration of 5 µg /L Mix thor oug hly and s ore

at r oom temperatur e in ambe glas scr ew ne ked vials or in the dar k T is inte mediate s an ar d is

ex e ted to bestable at r oom temperature for at leas two we ks Thiss a i ty shal be che ked Prior to

use, plac the s an ar d in an ultr asonic b th for 1 min

NOTE R ecalculate for particle stan ard suspensions having diferent compositions or concentrations

6.3.3.2 Wor king stan ar d of nominal 6 nm g old nano articles (5 ng /L) Prep r e the wor king

s an ar d b pipetting 5 µL of the s ock stan ar d (6.3.3.1) to 2 mL of purified wate in a 5 mL g las

measuring flask and fi to the mar k w ith purified wate resulting in a final mas conc ntration of 5 ng /L

Mix thor oug hly and s or e at room temperatur e in ambe glas scr ew ne ked vials A lthoug h this s andar d

is stable for several da ys, it is prep r ed daiy

6.3.3.3 Stock s an ar ds of ionic solutions of the p rticle’s elemental comp sition (1 0 µg /L)

A ssuming the suppled ionic stan ar d solution (6.3.2.2) has a conc ntration of 1 0 mg /L, pipet 5 µL of

the s an ar d to 2 mL purified wate in a 5 mL glas measuring flask an fi to the mar k with purified

wate r esulting in a conc ntration of 1 0 µg /L Mix thor oughly an s ore this inte mediate stan ar d in

ambe glas scr ew ne ked vials Pr ote ted fr om lght ,this inte mediate s an ar d is ex e ted to bes a le

at r oom temperatur e for at leas two we ks Thiss a i ty shal be che ked

NOTE R ecalculate for ionic stan ard solutions having diferent concentrations

6.3.3.4 Wor king s an ar ds of ionic solutions of the nano article analytes elemental comp sition (a

rang e of 0,2 to 5,0 µg /L can be used as a starting p int) Accor ding to Ta le 1, pipet the v lumes of the

s ock s an ar d (6.3.3.3) to ca 25 mL of purified wate in a 5 mL glas measuring flask an fi to the

mar k with purified wate Mix thoroughly A calbr ation curve is constructed fr om the r esulting wor king

s an ar ds in Ta le 1 Store the wor king s an ar ds at r oom temperatur e in glas b ttles Prote ted fr om

lg ht ,these inte mediate s andar dsar e stable at r oom temperatur e for the pe iod indicated in Ta le 1

Table 1 — Volumes for the preparatio of the wor king standards of the io ic stock solutio

Volume of the st ock stan ard

(6.3.3.3) dilut ed t o 5 mL p rif ied

water in mL

Ionic concentration of the working

stan ard (6.3.3.4) in µg L

Sta ility of the ionic working

stan ard in glas

6.4.2 S mple diution

In g ene al, the n mbe of pulses det ect ed in a time scan shal not ex ce d a ma imum n mbe of pulses

b sed on the dwel time (6.1) F or the ins rumental set ings used in this proc d r (6.5.1), a p rticle

n mbe conc ntration in the rang e of 2 × 1

6

particles/ t o 2 × 1

8

p rticles /L r sult in useful

measur ment data Ta le 2 gives the cor esp n ing mas conc ntrations for dife ent ty es an siz s

Silver (Ag)

Cerium o ide (CeO

2)

0,5ng L to 5 ng L 2ng L t o 2 0ng L 1 ng L to 1 0 0 ng L

Titanium dio ide (TiO

2)

Iron o ide (Fe

2

O

3)

Zinc o ide (ZnO)

0,2ng L t o 2 ng L 1 ng L to 1 0ng L 5 ng L to 5 0 ng L

If no information on the nano article conc ntration in a sample or aq eous suspension is a ai a le,

a 1 00 times diution is r commended as a s arting p int Based on the o se ved n mbe of pulses

in the analy sis of the diut ed sample, the di ution can then be ada t ed Diutions ar made in purified

wat er or, if s a i zation is r q ir d, in 5 mM sodium citrat e or sodium dode y l sulphat e ( SDS) in

purif ied wat er

6.5 Instrumental set ing s and perfor mance check

6.5.1 S t ing s of the ICP-MS system

The ins rument conf iguration for spICP-MS is not dife ent from s andard ICP-MS The efor , the

o timal ins rument set ings as pro ided b the sup le ar used

A 3 % nitric acid solution is used t o rinse sampl ng sy st em, tubing, et c of the ICP-MS befor an

in-betwe n ru s

In g ene al, dwel times in the rang e of 1 ms t o 1 ms ar comp tible with mos comme cial ICP-MS

sy st ems an can be used, though the pro a i ity of det ecting a single nano article pulse splt betwe n

two adjac nt measur ment win ow s inc eases as the dwel time is de r ased If long er dwel times

(> 0 ms) ar used, it is mor diff icult t o isolat e the p rticlesfrom the b ckgrou d in the data an mor

than one nano article ma be r gist er d b the det ect or in one dwel time event Short er dwel times

(< ms) ma be used, howeve , the ion plumeg ene at ed b the nano article in the plasma ( y ical width,

0,1 ms t o 0,3 ms) ma be divided o e multiple dwel time event an dedicat ed sof war is r q ir d t o

r cons ruct an q antify the p rticle pulse

In the case of low m/z v lues, as for Ti (48) an F e (5 ), int erfe enc s b p ly t omic ions such as SO

an ArO ma cause high b ckgroun levels, r n e ing smal p rticles invisible In that case, the r sult

ma be impro ed b monit oring an alt ernative ( e on ary) m/z pulse for the element of int er s or b

using a col sion/r action c l or othe t echniq e t o r mo e p ly t omic ions Whie in b th cases, the

a solut e sensitivity for the element of int er s wi be lowe , the signal-t o-noise ratio ( imp rtant for

dife entiating nano articles from the b ckgrou d)ma be highe

6.5.2 C ecking the per for manc e of the ICP-MS system

ICP-MS sy st ems ha e a pe formanc che k an an a ut o tune or man al tu e fu ction Car y out the

pe formanc che k If the c it eria of the pe formanc che k ar not met, pe form an ins rument u ing,

a ut o tu e or man al tu e, t o o timiz the ins rument The ICP-MS ma be tuned t o o timiz the

r sp nse for a p rticular m/ z v lue

Spe ial att ention should be paid that the sample introd ction sy st em of the ICP-MS is clean Analysis of

nano article suspensions with high particle conc ntrations ma lead t o contamination of the ICP-MS

ins rument, espe ialy the ins rument tubing, r sulting in contin ous b ckgrou d levels On the othe

han , ifhigh conc ntrations of othe ty e of samples ha e p s ed through the tubing, this can ca use

adsorptions giving e roneous r sult w hen det ermining the transp rt eff iciency an measuring true

samples If u sur , chang e the tubing of the sample introd ction sy st em Be ause spICP-MS normaly

uses diut ed samples suspensions, a set of tubing ma be r se ved for this method only

6.6 Deter mination of the transport eficiency

Sinc only a p rt of the introd c d sample r aches the plasma, know ledg e of the transp rt eff iciency

is r q ir d for the calculation of r sult It is det ermined using a k own nano article s an ard; in

this method, the 6 nm g old r fe enc p rticle (6.6.1) If not a aia le, any othe wel-charact eriz d

nano article suspension can be used; howeve , some diutions an conc ntrations should be

r calculat ed If nano articles of known siz ar a aia le but no conc ntration is known, an alt ernative

method can be used (6.6.2)

6.6.1 Deter minatio of transport eficiency based o me sured par ticle fr equency

Calculate the p rticle n mbe conc ntration in the wor king s an ard (6.3.3.2) using Form ulae (1) an (2):

is the mas pe p rticle (g)

The mas of a 6 nm g old nano article is 2,2 × 1

− 5

g an with a mas conc ntration of 5 ng L; this

r sult in a p rticle conc ntration C

p

= 2,3 × 1

7

p rticles /L

Analy se the working s an ard (6.3.3.2) using the set ings ac ording t o the proc d r (6.5.1) an

det ermine the p rticle flux in the plasma, i.e the n mbe of p rticle pulses pe se on in the time scan

Calculat e the transp rt eff iciency using F ormula (3):

q

C V

w he e

is the p rticle n mbe conc ntration (p rticles/ );

V is the sample flow (mL min);

6·1

4

is the conve sion fact or from min t o s an from mL t o L

W ith a s an ard ty e of nebulz r, η

n

is ex e t ed t o be in the orde of 2 % t o 5 %; howeve , nowaday s,

mor eff icient nebulz rs ar a aia le and ma be used

6.6.2 Determination of tr anspor t eficiency based o me sured particle size

If a nano article s an ard is a ai a le of w hich only the siz is k own, the transp rt efficiency can be

det ermined if a se ies of ionic s an ards (Ta le 1) ofthe same element as the nano article is analy sed

in the same se ies

Analy se the working s an ard of the particle suspension (6.3.3.2) an the working s an ards of the

ionic solutions (6.3.3.4) using the set ings ac ording t o the proc d r (6.5.1) Using lnear r gr s ion,

det ermine the cor elation coeff icient of the calbration l ne The cor elation coeff icient should be > , 99

Calculat e the transp rt efficiency using F ormula (4 ):

w he e

RF

ion

is the ICP-MS r sp nse fact or for the ion s an ard [cps/(µg L)];

V is the sample flow (mL min);

is the a e ag e nano article int ensity min s the b ckgrou d int ensity measur d for

nano-p rticlesin the working s an ard suspension (cps);

m

NP

is the the mas of the nano article (μg)