PMID- 23140950
OWN - NLM
STAT- MEDLINE
DCOM- 20130418
LR  - 20121112
IS  - 1873-4324 (Electronic)
IS  - 0003-2670 (Linking)
VI  - 754
DP  - 2012 Nov 19
TI  - Optimization of headspace experimental factors to determine chlorophenols in 
      water by means of headspace solid-phase microextraction and gas chromatography 
      coupled with mass spectrometry and parallel factor analysis.
PG  - 20-30
LID - S0003-2670(12)01422-5 [pii]
LID - 10.1016/j.aca.2012.10.003 [doi]
AB  - In this work an analytical procedure based on headspace solid-phase 
      microextraction and gas chromatography coupled with mass spectrometry 
      (HS-SPME-GC/MS) is proposed to determine chlorophenols with prior derivatization 
      step to improve analyte volatility and therefore the decision limit (CCalpha). After 
      optimization, the analytical procedure was applied to analyze river water 
      samples. The following analytes are studied: 2,4-dichlorophenol (2,4-DCP), 
      2,4,6-trichlorophenol (2,4,6-TrCP), 2,3,4,6-tetrachlorophenol (2,4,6-TeCP) and 
      pentachlorophenol (PCP). A D-optimal design is used to study the parameters 
      affecting the HS-SPME process and the derivatization step. Four experimental 
      factors at two levels and one factor at three levels were considered: (i) 
      equilibrium/extraction temperature, (ii) extraction time, (iii) sample volume, 
      (iv) agitation time and (v) equilibrium time. In addition two interactions 
      between four of them were considered. The D-optimal design enables the reduction 
      of the number of experiments from 48 to 18 while maintaining enough precision in 
      the estimation of the effects. As every analysis took 1h, the design is blocked 
      in 2 days. The second-order property of the PARAFAC (parallel factor analysis) 
      decomposition avoids the need of fitting a new calibration model each time that 
      the experimental conditions change. In consequence, the standardized loadings in 
      the sample mode estimated by a PARAFAC decomposition are the response used in the 
      design because they are proportional to the amount of analyte extracted. It has 
      been found that block effect is significant and that 60 degrees C equilibrium temperature 
      together with 25min extraction time are necessary to achieve the best extraction 
      for the chlorophenols analyzed. The other factors and interactions were not 
      significant. After that, a calibration based in a PARAFAC2 decomposition provided 
      the following values of CCalpha: 120, 208, 86, 39ngL(-1) for 2,4-DCP, 2,4,6-TrCP, 
      2,3,4,5-TeCP and PCP respectively for a probability of false positive set at 5%. 
      Also, the accuracy (trueness and precision) of the procedure is assessed. 
      Finally, river water samples have been analyzed with the proposed method showing 
      the absence of the chlorophenols studied.
CI  - Copyright (c) 2012 Elsevier B.V. All rights reserved.
FAU - Morales, Rocio
AU  - Morales R
AD  - Department of Chemistry, Faculty of Science, University of Burgos, Pza. Misael 
      Banuelos s/n, 09001 Burgos, Spain.
FAU - Cruz Ortiz, M
AU  - Cruz Ortiz M
FAU - Sarabia, Luis A
AU  - Sarabia LA
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20121009
PL  - Netherlands
TA  - Anal Chim Acta
JT  - Analytica chimica acta
JID - 0370534
RN  - 0 (Chlorophenols)
RN  - 0 (Water Pollutants, Chemical)
SB  - IM
MH  - Chlorophenols/*analysis
MH  - Gas Chromatography-Mass Spectrometry/instrumentation
MH  - Rivers/*chemistry
MH  - Software
MH  - *Solid Phase Microextraction/instrumentation
MH  - Water Pollutants, Chemical/*chemistry
EDAT- 2012/11/13 06:00
MHDA- 2013/04/20 06:00
CRDT- 2012/11/13 06:00
PHST- 2012/07/24 00:00 [received]
PHST- 2012/09/25 00:00 [revised]
PHST- 2012/10/02 00:00 [accepted]
PHST- 2012/11/13 06:00 [entrez]
PHST- 2012/11/13 06:00 [pubmed]
PHST- 2013/04/20 06:00 [medline]
AID - S0003-2670(12)01422-5 [pii]
AID - 10.1016/j.aca.2012.10.003 [doi]
PST - ppublish
SO  - Anal Chim Acta. 2012 Nov 19;754:20-30. doi: 10.1016/j.aca.2012.10.003. Epub 2012 
      Oct 9.