Determination of N-nitrosodiethanolaminheadspace solid phase microextraction us

s

, Mzam

n 19

Department of Chemistry, Shahr-e-Rey Branch, Islamic Azad University, P. O. Box 18735-334, Tehran, Islamic Republic of Iranc Mahd-e-Taban Investment Company, Vali-e-asr Ave., Tehran 1433895611, Islamic Republic of Iran

ectedskin, etc.,withriouse USn 65%

there are HPLC methods combined with UV [10,11], thermal

Contents lists available at SciVerse ScienceDirect

journal homepage: www.els

Talan

cence detector; PA, Polyacrylate; NDMA, N-nitrosodimethylamine; NDEA, N-

n-propylamine; NMOR, N-nitrosomorpholine; NDBA, N-nitrosodi-n-butylamine;

Talanta 105 (2013) 347353trochromatography [18], ion-exchange chromatography [11],h.davarani@gmail.com (S.S.H. Davarani).energy analyzer [12], uorescence [13] and tandem MS [1] detec-tion systems as well as gas chromatography coupled with ameionization, thermal energy analyzer, electron capture and massspectrometry detectors [1417]. Additionally, open-tubular elec-

0039-9140/$ - see front matter & 2012 Elsevier B.V. All rights reserved.

http://dx.doi.org/10.1016/j.talanta.2012.10.053

NDBzA, N-nitrosodibenzylamine; NDPheA, N-nitrosodiphenylamine; NDCHA, N-

nitrosodicyclohexylamine; NMEA, N-nitrosomethylethylamine; DLLME, Dispersive

liquidliquid microextractionn Corresponding author. Tel.: 98 21 22431667; fax: 98 21 22431663.E-mail addresses: ss-hosseiny@sbu.ac.ir,Several analytical methods have been used for the identicationand determination of NDELA at the mg mL1 level. Among them,

nitrosodiethylamine; NPIP, N-nitrosopiperidine; NPYR, N-nitrosopyrrolidine; TGA,

Thermal gravimetric analysis; PTFE, polytetrauoroethylene; NDPA, N-nitrosodi-drink, tobacco, rubber products and cosmetics [1]. Most nitrosa-mines, such as N-nitrosodiethanolamine (NDELA), are rated amongcarcinogenic or potentially carcinogenic compounds [2,3]. NDELA is

of them can lead to the production the most frequently detnitrosamine, NDELA [5]. NDELA is readily absorbed through theand is accumulated in organs such as the liver, bladder, kidneysand it induces chronic toxic effects [6,7]. Cosmetic products5256,750 mg Kg1 of NDELA have been notied as posing serisks [8]. In a study of cosmetic products in 19911992, by thFood and Drug Administration (FDA), NDELA was determined iof the samples at levels of up to 3 mg mL1 [9].

Abbreviations: NDELA, N-nitrosodiethanolamine; LLE, Liquidliquid extraction;

SPE, Solid phase extraction; HS-SPME, Headspace solid phase microextraction;

PDMS-DVB, Polydimethylsiloxane-divinylbenzene; NCD, Nitrogen chemilumines-1. Introduction

N-nitrosamines are hazardous chemical compounds that may bepresent as contaminants in a number of products including food,

a common contaminant in many commercial cosmetic productssuch as hand creams, face creams, shampoos, moisturizing lotionsand other hand and body products [4]. The most commonly usedamines in cosmetic products are di- and tri-ethanolamine and bothArticle history:

Received 23 July 2012

Received in revised form

14 October 2012

Accepted 16 October 2012Available online 26 October 2012

Keywords:

N-nitrosodiethanolamine (NDELA)

Headspace solid phase microextraction

Cosmetic

Aluminum hydroxide grafting

Gas chromatographymass spectrometrya b s t r a c t

A method based on headspace solid phase microextraction with a new ber, coupled with gas

chromatographymass spectrometry was developed for the determination of NDELA in cosmetic

samples. The ber provides Lewis acidbase interaction between its surface and analyte functional

groups. The ber was prepared by grafting aluminum tri-tert-butoxide on the surface of a fused silica.

The optimization of SPME conditions showed that NDELA can be most effectively extracted at 70 1C, in15 min, with a sample volume of 0.5 (Vs/Vt), stirring rate of 150 rpm, desorption time of 5 min,

desorption temperature of 260 1C and at 12.5% (w/w) concentration of NaCl. Under the optimizedconditions, LOD of 1 mg Kg1 and a calibration curve with correlation coefcients greater than 0.9897and a linearity range from 6 to 10000 mg Kg1 were obtained. The intra-day and inter-day precision andaccuracy were evaluated at four concentration levels. All of the values for accuracy and precision were

lower than the acceptable limit of 15%. The ber to ber repeatability was 8.7%. The method was

applied for the analysis of real samples including hair shampoo, body shampoo, dishwashing liquid and

hand washing liquid. Relative recoveries were achieved in the range of 9599%.

& 2012 Elsevier B.V. All rights reserved.a r t i c l e i n f ografted fused silica ber followed by gaspectrometry analysis

Saied Saeed Hosseiny Davarani a,n, Leila Masoomi a

Hamid Reza Lot Zadeh Zhad b, Omid Sadeghi b, Aa Department of Chemistry, Faculty of Sciences, Shahid Beheshti University G. C., Tehrabe in cosmetic products bying a novel aluminum hydroxidechromatographymass

ohammad Hossein Banitaba a,Samiei c

83963113, Islamic Republic of Iran

evier.com/locate/talanta

ta

2 2 2

cation was also conrmed by the retention time of the target ion

S.S.H. Davarani et al. / Talanta 105 (2013) 347353348differential pulse polarography [19] and thin layer chromatography[20] have been used for the analysis of NDELA. Furthermore,an ion-pair liquid chromatography method with C16-cetyltrimethylammonium chloride, as the ion-pair agent, for thedetermination of four non-volatile N-nitrosoamino acids [21] andthe reverse phase HPLC method with anion complex agent and UVdetection [22] have been reported.

A number of conventional extraction and clean-up proceduresfor determining nitrosamines have been described, including low-temperature vacuum distillation, liquidliquid extraction (LLE),and solid phase extraction (SPE) [2325]. The US EPA method forthe determination of nitrosamines in water samples is based on aSPEGCMS/MS analysis [26]. An ISO standard method for thedetermination of N-nitrosodiethanolamine in cosmetics is alsoavailable [1]. In this method, sample clean-up is performed usingeither SPE with a C18 cartridge or LLE using dichloromethanewhen the samples are not dispersible in water. The extracts arethen analyzed by HPLCMS/MS.

All the methods described above suffer from some disadvan-tages, such as application of complex and time-cosuming proce-dures for sample preparations (i.e., solvent extraction, ltration,etc.), hazardous waste production and rather expensive instru-mention (e.g., GCMS/MS or HPLCMS/MS).

Solid phase microextraction (SPME) developed by Arthur andPawliszyn in 1989 [27], is a solvent free extraction method whichhas many advantages compared to conventional preparationmethods. It can be easily automated [28] and does not requireenvironmentally hazardous solvents [29]. SPME has found a widerange of applications in environmental science, industrialhygiene, process monitoring, forensic sciences, toxicology, biol-ogy, drugs and foods [2832]. Commercially available SPME bershave been used for the analysis of various N-nitrosamines inwastewater [33], beer [34] and food [35]. Grebel et al. [33]studied the determination of N-nitrosamines in wastewater usinga commercially available polydimethylsiloxane-divinylbenzene(PDMS-DVB) ber and three gas chromatography (GC) detectionsystems [nitrogen chemiluminescence detector (NCD), nitrogenphosphorus detector and chemical ionization mass spectrometry].They showed that the application of HS-SPME in conjunction witha GCNCD instrument is an excellent choice for the analysis of N-nitrosamines, reducing the total analysis time to only 1.25 h(versus 320 h for other isolation techniques) and providing goodselectivity and low detection limits. Andrade et al. [35] comparedPDMS-DVB and polyacrylate (PA) SPME bers for HS-SPMEGC-thermal energy analyzer detection of N-nitrosamines. This inves-tigation showed that the PDMS-DVB ber with intermediatepolarity is more sensitive to N-nitrosodimethylamine (NDMA)and N-nitrosodiethylamine (NDEA). On the other hand, the polarPA-coated ber, was more efcient for the extraction of the morepolar compounds of N-nitrosopiperidine (NPIP) and N-nitroso-pyrrolidine (NPYR).

Commercial SPME bers are commonly prepared by simplephysical deposition of the coatings on the surface of the fusedsilica ber [29]. Commercial SPME sorbent coatings have gener-ally good extraction properties; however some aspects of theirperformance can be improved such as chemical, thermal andmechanical stability. They are also expensive and cover a limitedrange of the sample polarity. Most commercially available bers(such as PDMS) are nonpolar and the others (e.g., Carboxen/PDMS), which are relatively polar, are characterized by a reducedthermal stability [36]. To improve the performance of SPME forNDELA, which is a small polar molecule, a new ber coating has tobe developed. In this work, we introduce a new surface modica-tion route for the preparation of a new SPME coating based on thecovalent grafting process. This work is also the rst report on the

application of SPME for the extraction of N-nitrosamines fromand the qualier-to-target ion ratio. A mass to charge ratio of 72was used as the qualier ion. Thermal gravimetric analysis (TGA)was carried out on a Bahr STA-503 instrument under air atmo-sphere. The SPME syringe was purchased from Azar Electrode Co.(Uromieh, Iran). A Heidolph heater/stirrer was used for heatingand stirring the samples.

2.3. Preparation of SPME ber

The aluminum hydroxide grafted fused silica ber was pre-pared according to a grafting route [42,43]. The grafting process ofaluminum hydroxide on fused silica is shown schematically inFig. 1. The polymeric coating of a damaged fused silica column(O.D.0.32 mm and length of 7 cm) was removed by burning in aame. Both ends were then sealed by ame. Then, its surface wascleaned with acetone and water. Afterwards, the ber surface wasactivated by NaOH solution (2 M) for 4 h. After washing the berwith water and drying under vacuum at 70 1C, 1 cm of fused silica

1cosmetic products and the application of SPME for the extractionof NDELA from any media. For the preparation of the ber, astraightforward grafting process was used for the modication ofa fused silica surface using aluminum tri-tert-butoxide. A berbased on aluminum compounds that functions as a Lewis acid[37] as well as an oxophile [38] would be advantageous for theextraction of NDELA. This expectation is in accordance with theresults of some previous studies on modied adsorbents for thecapturing of N-nitrosamines, in which the aluminum incorpora-tion into the framework of MCM-41 and other silica basedadsorbents, enhances their adsorptive capacity owing to thegeneration of acidic sites in the adsorbent [3941]. The affectingparameters, including salting out effect, stirring rate, samplevolume, extraction temperature and extraction time were opti-mized. The effects of desorption temperature and desorption timeon the obtained response from GCMS analysis were studied andoptimized. Finally, the developed method was applied to realsample analysis.

2. Material and methods

2.1. Reagents and materials

The N-nitrosodiethanolamine and sodium chloride wereacquired from Sigma-Aldrich (Milwaukee, WI, USA). Aluminumtri-tert-butoxide was obtained from Merck (Darmstadt, Ger-many). All other chemicals including toluene and NaOH werereagent-grade products and purchased from Merck.

2.2. Apparatus

The GCMS analyses were performed on a Shimadzu Qp-2010plus (Kyoto, Japan). Helium was used as the carrier gas with aow rate of 1 mL min1. The separation of extracted compoundswas performed on an RTX-5 MS column (30 m length, 0.025 mmI.D., 0.25 mm df, crossbond, 5% diphenyl-95% dimethyl polysilox-ane). The column was obtained from Chromspec company (Brock-ville, Canada). The initial column temperature was set at 80 1C.Then, the temperature was increased to 100 1C at a rate of 4 1Cmin1 and maintained for 6 min. Finally, the column temperaturewas raised up to 250 1C at a rate of 40 1C min1 and held for2 min. The transfer line temperature was 260 1C. Electron ioniza-tion mass spectra were recorded at 70 eV ionization energy. Fullscan spectra were recorded and NDELA was quantied using theion of m/z87 (M-1-CH CH OH ) as the target ion. The identi-was placed in a 0.1 mol L aluminum tri-tert-butoxide solution

in toluene, under N2 atmosphere for 24 h to allow the covalentattachment of aluminum hydroxide to the substrate. Then, theber was heated at 200 1C for 20 min. Finally, it was washed bytoluene followed by washing with chloroform, drying at roomtemperature and conditioning at 260 1C in a ow of N2 gas. Ascited in previous works the grafting process can proceed withhigh efciency [44].

2.4. The SPME GCMS analysis

For the headspace solid phase microextraction (HS-SPME)procedure, a 10 mL of water diluted sample (with sample:waterratio of 3 g:5 g) and 1 g of NaCl with a magnetic stirring bar wereplaced in a 20 mL sample vial. After sealing the vial by polytetra-uoroethylene (PTFE) septum, the vial was placed on a stirrer andwas stirred at a rate of 250 rpm for 1 min to homogenize themixture. The ber was then placed in the inner needle of a syringeand withdrawn into the outer needle of the syringe. The outerneedle of the syringe was passed through the PTFE septum andthe ber was exposed in the headspace above the aqueous phaseand the solution was stirred at a rate of 150 rpm, at 70 1C for15 min. Then the ber was introduced into the GC injection portat a temperature of 260 1C for 5 min for the desorption of theanalyte.

Initially, selected experiments were performed to optimize themain parameters affecting the GCMS response of the extractedNDELA from water-diluted sample (containing 2000 mg Kg1

NDELA and 1 g of NaCl). These parameters were the percentage

of added sodium chloride (%NaCl), stirring rate, sample volume(Vs/Vt), extraction temperature (Text), extraction time (text), deso-rption temperature (Tdes) and desorption time (tdes). The para-meters were optimized by varying one of them at a time, keepingthe other parameters constant. The extractions were repeatedthree times for each condition. A ber blank was run betweeneach sample to avoid carry over effects.

2.5. Method validation

The analytical performance of the proposed method wasvalidated through the determination of linearity range, correla-tion coefcient, limit of detection (LOD), limit of quantication(LOQ), accuracy and precision under the optimized SPME condi-tions. The linear range was obtained by standard addition methodwith seven concentration levels. The linearity of the calibrationcurve was veried by Mandel tting test at the condence level of95%. A diluted mixture (with water:mixture ratio of 3 g:5 g) of ahomemade shampoo containing the major components of sham-poo, except coconut diethanol amide which is the main source ofNDELA was used to evaluate LOD and LOQ. Standard solutionswith concentrations near LOD and LOQ values were prepared byusing this diluted mixture. Two standard curves were prepared inthe concentration ranges of the LOD (15 mg Kg1) and LOQ(412 mg Kg1). Then, the following equations were used to

ting

S.S.H. Davarani et al. / Talanta 105 (2013) 347353 349Fig. 1. Proposed scheme of possible covalent attachment of aluminum to thesubstrate.

Fig. 2. Scanning electron micrograph of fused silica ber (a) before starting the graf

of 100 and (2) magnication of 15,000 .calculate the LOD and LOQ, respectively [45]:

LOD 3 s=m1LOQ 10 s=m2

where s is the standard deviation of the response sample blank(estimated from the 10 independent sample blanks measuredonce each), m1 is the slope of the standard curve in the concen-tration range of LOD and m2 is the slope of the standard curve inthe concentration range of LOQ.

The accuracy and precision of the method were determined byperforming ve consecutive analysis of water-diluted samplesspiked with NDELA at LOQ concentration level (3.4 mg Kg1) andthree concentrations representing the low, medium and high

process (b) after modication of surface via the grafting process. (1) magnication

portions of the standard curves (8, 1000 and 8000 mg Kg1). Intra-day accuracy and precision were calculated on a single day usingve replicates at each concentration level. Inter-day accuracy andprecision were calculated using ve replicates at each concentra-tion level over ve consecutive days. The ber to ber repeat-ability was estimated using three bers, which were constructedunder the same conditions. Three replicates were carried out oneach ber and the extractions were accomplished from a200 mg Kg1 standard solution.

2.6. Real Samples

The proposed method was applied for the determination ofNDELA in different cosmetic samples. Commercial cosmeticproducts from various manufactures were purchased from localstores in Tehran (Iran) from 2008 to 2010 and kept at 4 1C untilanalysis. The real samples were analyzed according to theprocedure described in Section 2.4 under optimum conditions.Standard addition method was used for the quantication of

tioned at 300 1C for an hour without any signicant loss in the

recommended conditioning temperature for commercial bers(200280 1C), e.g. Carboxen/divinylbenzene ber. The thermalstability of this ber is better than that of commercial bers,because its surface is simply covered by the grafted aluminuimwhich is covalently attached to the substrate. The ber proved tobe stable and reusable for more than 85 extractions and deso-rptions at 260 1C.

3.2. Optimization of extraction conditions

To obtain a reproducible and sensitive method based onheadspace SPME, the inuence of several parameters includingsalt concentration, stirring rate, sample volume, extraction tem-perature, extraction time, desorption temperature and desorptiontime were considered. HS-SPME is favorable for the extraction ofNDELA since it is known to extend the ber lifetime.

3.2.1. Salting out effect

To study the effect of ionic strength in the extraction process,different amounts of NaCl were added into the samples. When theamount of salt increased up to 12.5%, the GC response for theanalyte increased. However, further addition of salt to the solu-tion decreased the GC response. An initial increase and then adecrease in GC response with increase in the concentration of

S.S.H. Davarani et al. / Talanta 105 (2013) 347353350extraction efciency. This temperature is higher than the

Fig. 3. Effect of stirring rate on the extraction of NDELA using aluminum hydroxidegrafted fused silica SPME ber. Extraction conditions: extraction temperature (Text)

of 60 1C, extraction time (text) of 30 min, desorption temperature (Tdes) of 260 1C,desorption time (tdes) of 5 min and 12.5% salt addition. All results are presented as aNDELA in cosmetics.

3. Result and discussion

3.1. Aluminum hydroxide fused silica ber properties

The proposed ber is simply composed of a layer of graftedaluminum hydroxide on a fused silica substrate and has lowporosity and thickness. Fig. 2 shows the SEM images from thesurface of the fused silica ber before and after surface modica-tion. Although some changes occur in the morphology of thefused silica surface, it is obvious from these gures that noappreciable changes in the thickness of the ber occurs duringthe modication of the surface.

In order to show that the presence of aluminum hydroxide onthe surface of the ber is important for the extraction of NDELA,an aluminum hydroxide grafted fused silica ber was comparedto an activated-surface fused silica ber which was prepared byusing NaOH solution. While the aluminum hydroxide graftedfused silica ber extracted NDELA, no signicant extraction wasobtained with the activated-surface fused silica.

As expected, thermal gravimetric analysis (TGA) of the bershows no mass loss, even up to 500 1C. The ber can be condi-mean of triplicate experiment with one standard deviation.Fig. 4. Effects of (a) extraction temperature; and (b) extraction time; on theextraction of NDELA using aluminum hydroxide grafted fused silica SPME ber.

Extraction conditions: stirring rate at 150 rpm, desorption temperature (Tdes) of

260 1C, desorption time (tdes) of 5 min, 12.5% salt, sample volume of 0.5 andextraction time (text) of 30 min for (a) and extraction temperature (Text) of 70 1C for(b). All results are presented as a mean of triplicate experiment with one standarddeviation.

sodium chloride can be explained by two simultaneously occur-ring processes. Initially, up to 12.5% (w/w) of NaCl concentration,the GC response was increased due to the salting out effect (i.e.,decreasing analyte solubility in aqueous phase) which enhancesthe partitioning of analyte into the headspace [46,47]; but as thesalt concentration increases, an electrostatic interaction of ana-lytes with salt ions in the solution dominates, affecting theamount of analyte driven to the headspase. Thus, 12.5% (w/w)NaCl was chosen as the optimum value for subsequentexperiments.

3.2.2. Stirring rate

The effect of stirring rate for aluminum hydroxide graftedfused silica SPME ber is shown in Fig. 3. The stirring rate rangedbetween 140 rpm and 350 rpm. Higher stirring rates could not bestudied due to the excessive formation of foam. In the stirringrates above 150 rpm, the GC response decreased signicantly.This decrease might be attributed to the some foam formation atstirring rates above 150 rpm. Thus, 150 rpm was selected as theoptimum stirring rate.

3.2.3. Sample volume

Since the sensitivity of the SPME procedures is proportional tothe amount of analyte in the sample, it is expected that increasingthe sample volume will augment the GC response. However, fromthe SPME theory, if the sample volume becomes signicantly

larger than the ber and headspace capacities, no enhancement ofthe response can be achieved by increasing the volume of sample.In order to evaluate the sample volume effect on the HS-SPMEefciency, a set of experiments were carried out. The range ofsample volume tested was from 4 to 16 mL. Results show thatwhen sample volume was xed at 10 mL (sample volume/totalvolume0.5) a maximum response could be identied.

3.2.4. Extraction temperature

In this study, extraction temperatures were studied in a rangefrom 45 to 85 1C at 30 min extraction time. Fig. 4a shows theeffect of extraction temperature on the extraction efciency. Atthe temperatures lower than 45 1C, the NDELA extraction was lowbut when the temperature increased up to 70 1C, the amount ofextracted analyte increased. However, for temperatures higherthan 70 1C, the amount of extracted analyte started to decrease.Indeed, temperature can inuence the extraction efciency due toseveral different effects. From one side, headspace/sample parti-tion coefcient of the analyte increases with enhanced

Table 1Intra- and inter-day accuracy and precision for the determination of NDELA.

Concentration (mg Kg1) Precision Accuracy

Mean7SD (mg Kg1) CV (%) Bias (%)

Intra-day (n5)3.40 3.5070.24 6.9 2.98.00 8.2170.49 6.0 2.61000 962750 5.3 3.88000 82707256 3.1 3.4

Inter-day (n5)3.40 3.6170.25 6.9 6.28.00 8.3070.60 7.2 3.71000 953762 6.5 4.78000 83217286 3.4 4.0

S.S.H. Davarani et al. / Talanta 105 (2013) 347353 351Fig. 5. Effect of (a) desorption temperature; and (b) desorption time; on theextraction of NDELA using aluminum hydroxide grafted fused silica SPME ber.

Extraction conditions: extraction temperature (Text) of 70 1C, extraction time (text)of 15 min, stirring rate at 150 rpm, 12.5% salt addition and desorption time (tdes) of

5 min for (a) and desorption temperature (tdes) 260 1C for (b). All results are

presented as a mean of triplicate experiment with one standard deviation.Fig. 6. (a) Typical GCMS chromatogram of extracted NDELA from hair shampoo(160 mg Kg1) with the aluminum hydroxide-fused silica SPME ber underoptimum conditions and (b) mass spectrum of NDELA obtained under experi-mental conditions.

temperature which leads to a higher concentration of the analytein the headspace and results in a higher amount of extractedanalyte at equilibrium conditions. However, higher temperaturesmay also have the negative effect of a less favorable coating/headspace partition coefcient because the ber equilibriumprocess is an exothermic process and any increase in samplingtemperature will decrease recovery [48]. In this study the opti-mum extraction temperature was taken as 70 1C.

3.2.5. Extraction time

In the HS-SPME technique, the equilibrium of the analytebetween the vapor phase and the ber coating is crucial. Thus,the extraction time was optimized to determine the optimumtime to reach the equilibrium. Fig. 4b shows the effect of theextraction time on the GC response of NDELA. The highest GCresponse was obtained with a time of 15 min for NDELA and atlonger extraction times, no signicant changes in GC responsewere observed. The extraction time of 15 min is shorter than all

other extraction times that have been reported in other works onthe extraction of NDELA [1,22].

3.2.6. Desorption temperature and desorption time

It is important to study the desorption temperature anddesorption time to ensure that there is no carryover effects, Theber coating stays intact and no substantial changes occur in theproperties of the coating at the applied temperature. Variousdesorption temperatures from 150 to 280 1C and various deso-rption times from 1 to 7 min were investigated. The optimumdesorption temperature and the optimum desorption time werefound to be 260 1C (Fig. 5a) and 5 min (Fig. 5b), respectively. Sincethere was no signicant change in GC response in temperatures260280 1C, the lowest temperature in this range was chosen asthe optimum temperature for the desorption of NDELA.

3.3. Method validation

The calibration curve was prepared over a linear range from6 to 10000 mg Kg1 with correlation coefcient (R) of greater than0.9897. In order to verify if the tted linear model effectivelyprovided the best t, Mandel tting test was used. The F valuefound at the 95% condence level was lower than that reported inthe F-table (p40.05), showing that a quadratic model is notsignicantly better than a linear model for tting the experi-mental data. The estimated LOD and LOQ were 1 and 3.3 mg Kg1,respectively. The values of intra-day precision and accuracy andinter-day precision and accuracy are provided in Table 1. Theaccuracy and precision should not exceed 15%, except for LOQ

Table 2Determination of NDELA in real samples.

Samples NDELA content7SDa (mg Kg1) Recovery7SDb (%)

Shampoo 1 8375 9670.5Shampoo 2 160710 9775Body shampoo 5073 9972Dishwashing liquid 48007100 9574Hand washing liquid 68007110 9872

a n5.b n5.

Table 3A comparison between the proposed method with some other published works for N-nitrosamine analysis.

Sample matrix Analytes Sample

preparation

method

Detection method Linear range Limit of detection Recovery% RSD% Ref.

Cosmetics NDELA HS-SPME GCMS

Cosmetics NDELA SPE/LLE Ion-pair HPLCUV

Cosmetics NDELA SPE/LLE LCMS/MS

Cosmetics NDMAa, NDEAb, NDPAc, NMORd,

NDBAe, NDBzAf, NPYRg, NPIPh,

NDPheAi, NDCHAj

SPE GCMS/MS

Wastewater NDMAa, NDEAb, NDPAc, NMORd,

NPYRg, NPIPh, NDBAeHS-SPMEl GCNCDo

Food NDMAa, NDEAb, NPYRg, NPIPh HS-SPMEm GCTEA

Beer NDMAa HS-SPMEl GCMS

o

S.S.H. Davarani et al. / Talanta 105 (2013) 347353352Drinking water NDMAa, NMEAk, NDEAb, NDPAc,

NDBAe, NPYRg, NPIPhSPE GCMS/MS

Water samples NDMAa, NMORd, NMEAk, NPYRg Not required HPLCCL

Meat products NDMAa, NDEAb, NDPAc, NPYRg,

NPIPh, NDBAeSPE GCGCNCD

Meat products NDMAa, NMEAk, NDEAb, NPYRg,

NMORd, NDPAc, NPIPh, NDBAe,

NDPheAi

DLLMEn GCMS

a N-nitrosodimethylamine.b N-nitrosodiethylamine.c N-nitrosodi-n-propylamine.d N-nitrosomorpholine.e N-nitrosodi-n-butylamine.f N-nitrosodibenzylamine.g N-nitrosopyrrolidine.h N-nitrosopiperidine.i N-nitrosodiphenylamine.j N-nitrosodicyclohexylamine.k N-nitrosomethylethylamine.l With polydimethylsiloxane/divinylbenzene ber.m With polydimethylsiloxane/divinylbenzene and polyacrylate bers.n Dispersive liquidliquid microextraction.

o Nitrogen chemiluminesence detector.610000 (mg Kg1) 2 (mg Kg1) 9599% o6.1 This work3010000 (mg L1) 10 (mg L1) 86.9/51.8 0.9/5.6 [22]01600 (mg Kg1) 22.8 (mg g1) 48.3112.7/

41.360.3

No data [1]

5010000 (mg L1) 2.510 (mg Kg1) 85.2102.3 3.059.24 [50]

No data 15110 (ng L1) 94115 930.7 [33]

60720 ng (for 2.5 g

of sample)

3 (mg Kg1) 105110 512 [35]

800032000(mg L1) 0.8830 (mg L1) 4.6 [34]0.550 (ng L1) 0.260.66 (ng L1) 87.1104 411 [26]

51000 (ng L1) 1.5 (ng L1) 90.4111.4 0.74.5 [51]1400 (mg L1) 1.613.86 (mg L1) 7685 No data [52]

0.05200 (mg L1) 0.120.46(mg Kg1)

94.5 5.910 [53]

concentration level in which accuracy and precision should not

A new aluminum hydroxide grafted fused silica SPME ber

[9] /http://www.fda.gov/ICECI/Inspections/InspectionGuides/ucm074952.htm?utm_campaign=Google2&utm_source=fdaSearch&utm_medium=website&utm_term=cosmetic%20NDELA%2065%&utm_content=1S.

[10] R. Schwarzenbach, I.J.P. Schmid, J. Chromatogr. A 472 (1989) 231242.[11] B. Buchele, L. Hofmann, J. Lang, Fresenius J. Anal. Chem. 336 (1990) 328332.

S.S.H. Davarani et al. / Talanta 105 (2013) 347353 353was successfully prepared by means of a grafting process for therst time. This new ber showed superior extraction efciency forNDELA in cosmetics compared to other proposed methods(Table 3). The synthesized ber had good thermal stability up to500 1C. It could also be used at high temperatures up to 300 1Cwithout any signicant changes in its properties. The effect ofvarious parameters on the HS-SPMEGCMS analysis of NDELAwere studied by using this ber and the optimized conditionswere applied to the analysis of real samples. Good recoveries forNDELA determination in real samples were obtained with goodprecision. Being rapid, inexpensive and solvent free, this methodis suitable for routine analysis of NDELA in cosmetic products.

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