Table 111. Interference Studya Added compound
Hexyl alcohol Benzyl alcohol 2 -Phenoxvethanol Methyl cellusolve Naphthalene Acenaphthene Hexanoic acid Octanoic acid Butanoic acid
1 1
r
Result
procedure are used, pentachlorophenol losses will be negligible as will losses due to chlorination and oxidation of other phenols.
ACKNOWLEDGMENT No interference
1 -2 to 3% recovery without MeOH wash. No interference after MeOH wash
We thank M. D. Grieser and M. D. Arguello for their preliminary work on the sorption of organics by A-26 resin, and M. Avery for mass spectrographic identification of chlorination products of phenols. The authors are also grateful to H. J. Svec for valuable discussions and suggestions, and to J. J. Richard and G. A. Junk for their assistance.
Interference with phenol and cresols on OV-17
='Samples contained approximately 1 ppm each of several phenols and 20 ppm of each added compound. and alkyl phenols added to tap water coincided with enhanced recoveries of chlorinated phenols. Addition of low concentrations of chloramine T to very dilute aqueous solutions of phenols caused similar results. Letting 3,5-dimethylphenol solutions prepared in chlorinated tap water stand for a few minutes resulted in -40% loss. New GC peaks from extracts from this solution were positively identified by mass spectrometry as being the di- and trichlorodimethylphenols. Chlorination reactions during the determination of phenols can be prevented by addition of hydroxylamine hydrochloride. On real samples, however, it must be recognized that chlorination reactions may have occurred before the sample was taken. The recovery of pentachlorophenol was affected by the amount of reductants used to prevent oxidation and chlorination. The more reductant added, the lower its recovery. If the amounts of reductants specified in the recommended
LITERATURE CITED (1) A. K. Burnham, G. V. Calder. J. S. Fritz, G. A. Junk, H. J. Svec, and R. Willis, Anal. Chem., 44, 139 (1972). (2) A. K. Burnham. G. V. Calder, J. S.Fritz, G. A. Junk, H. J. Svec, and R. Vick, J. Am. Water Works ASSOC.,65, 722 (1973). (3) J. J. Richardand J. S.Fritz, Talanta, 21, 91 (1974). (4) J. L. Witiak, G. A. Junk, G. V. Calder, J. S. Fritz, and H. J. Svec, J. Org. Chem., 38, 3066 (1973). (5) G. A. Junk, J. J. Richard, M. D. Grieser, D. Witiak, J. L. Witiak, M. D. Arguello, R. Vick. H. J. Svec, J. S. Fritz, and G. V. Calder, J. Chromatogr., 99, 745 (1974). (6) J. J. Richard, G. A. Junk, M. Avery. N. Nehring, J. S. Fritz, and H. J. Svec, J. Environ. Qual., (submitted for publication.) (7) W. D. Beer, Wis. Z. KarlMrxUniv., 8, 67, (1956/59). (8) R. L. Whitlock, S. Siggia. and J. E. Smola, Anal. Chem., 44, 532 (1972). (9) "Standard Methods for Examination of Water and Waste Water", 13th ed., American Public Health Association, New York, NY, 1971 (10) A. W. Briedenbach, J. J. Lichtenberg, C. F. Henke, D. J Smith, J. W. Eichelberger. and H. Steirli, U.S. Dept. of Interior Pub. WP-22 (Nov. 66). (11) J. S. Eichelberger, R. C. Dressman, and J. E. Longbottom, Environ. Sci. Technoi,, 4, 576 (1970). (12) J. A. Vinson, G. A. Burke, B. L. Flager, D. R. Casper. W. A. Nylander, and R. J. Middlemiss. Environ. Lett., 5, 199 (1973). (13) R. B. Dean, News Environ. Res. Cincinnati, July 5 , 1974.
RECEIVEDfor review January 13, 1975. Accepted March 13, 1975. Appreciation is expressed to the National Science Foundation (Grant No. GP-32526) for financial support.
Modern Liquid Chromatography on Spherosil Jean Vermont, Michel Deleuil,' A. J. de Vries,' and C. L. Guillemin Centre de Recherches Rhbne-Progil, 93308 Aubervilliers, France
The separation ability of various types of Spherosil, as a packing materlal for high performance Liquid-Solid and Liquid-Liquid Chromatography, has been studied as a function of various parameters: column geometry, particle size, specific surface area, and coating by a stationary phase. The effect of column geometry with respect to particle size has been demonstrated by introducing a dimensionless number, the Knox-Parcher ratio: dpL/dc2,which should be as small as possible in order to obtain maximum column efficiency. Fast separations have been obtained by Liquid-Solid Chromatography under low pressure drops (5 bars), with columns of short length (5 cm), packed with small particle size (5-10 M ) of Spherosil of high specific surface area (600800 m2/g). In Liquid-Liquid Chromatography, an appropriate heating treatment of Spherosll, coated with large amounts of &p'-oxydipropionltrile, allows rapid separations without base-line drift and without presaturatlon of the liquid carrier.
Present address, Centre de Recherches RhBne-Progil de la Croix de Berny.
The first chromatographic applications of Spherosil have been started with liquid phase exclusion chromatography as early as 1966 by De Vries and Le Page (1-3), followed by numerous other studies in the field of liquid (4-11) and gas chromatography (12-16). For the purpose of the present study in Liquid-Solid (LSC) and Liquid-Liquid Chromatography (LLC), we have used a number of commercial and experimental batches of Spherosil with particle sizes below 40 p , fractionated by sieving in order to obtain particles of different size ranges, between 10 and 40 p. Moreover 5- to 10-p particles directly generated a t that size were used without any subsequent sieving. The physical properties of the materials used are given in Table I.
EXPERIMENTAL Apparatus. Systematic experiments were performed on a homemade liquid chromatograph using a membrane pump Orlita, type M3S 4/4 and a LDC detector: R.I. model 1103, or U.V. model 1205 (254 nm), depending on the nature of the mixtures to be separated. Before reaching the pump, the solvent was continuously degassed, then passed through a filter. Downstream from the pump, two
ANALYTICALCHEMISTRY, VOL. 47, NO. 8, JULY 1975
1329
Table I. Physical Data of Spherosil Batches Used in the Present Work Specific surface area
Mean diamefer
Pore volume,
Internal bead
Types of Spherosil
S, m2/g
of the pores, A
ml/g
porosity, e s
m2/g
X O A 1000 (experimental) XOA 1000 (experimental) XOA 600 (commercial) X O A 400 (commercial) X O A 200 (commercial) XOB 075 (commercial)
1100
20 35 90 95 160 310
0.55 0.78 1.30 1.13 0.96 1.02
0.548 0.632 0.741 0.717 0.679 0.693
498 316 150 132 65 33
0
r-
r n
a60
580 460 203 1 oa
r
r
i
B
Figure 1. Effect of
i
dehydration of Spherosil in LSC
I
Separation of benzene (I), naphthalene (2), and anthracene (3) in LSC on Spherosil XOA 400 (460 rn2/g); particle size, 10-20 p : column, i.d. 4 rnm, length, 22 c,m. Carrier: dry hexane, flow-rate, 1 ml/rnln; pressure drop, 10 bars. ( A ) Undehydrated Spherosil. ( B )dehydrated Spherosil
Bourdon tubes connected with a capillary tube of 0.25-mm i.d. acted as a pulsation damper. Two manometers mounted upstream and downstream from this system indicated that pulsations are smoothed to f3% of the inlet pressure. Several injection port systems were built according to the design reported by Halasz et al. ( 1 7 ) ,and fitted on stainless steel columns of different inside diameters: 2, 4, 6, and 8 mm. Samples were introduced into the top of the column through a septum, by using a microsyringe (SGE type B: 5 wl), without stop-flow technique. The connection tube between the column and the detector was kept to the minimum possible length to avoid peak broadening outside the column. All the fittings were Carlo Erba types, currently used in our GC circuits. However, very short columns developed in the course of this study, working under low pressure drops, were simply operated with the aid of a home-made pressurized coil pumping system instead of the Orlita pump. Column Packing Procedure. The first and the hardest task in LC is the preparation of a satisfactory column: several manual dry packing procedures have already been reported in literature (11, 18, 19); however, according to our own experience, they often depend on the skill of the operator. In the case of very small particles
2.20 2.20 2.20 5.25 5.25 62.50 62.50 15.60 15.60 6.90 6.90 6.90 20.60 93.70 25 25 25 125 31.20 31.20 156 156 39.20 62.50 375 375 375 375 25 2 50 250 250 2 50 75 281 281 344 344 344
HETP, m m
0.05 0.055 0.0625 0.075 0.10 0.125 0.35 0.10 0.12 0.142 0.15 0.155 0.24 0.35 0.12 0.24 0.28 0.175 0.18 0.30 0.35 0.50 0.206 0.30 0.36 0.42 0.45 0.50 0.15 0.34 0.40 0.47 0.90 0.22 0.5 0.7 0.4 0.6 0.84
decreasing the ratio not only allows more efficient columns to be obtained, but also that the spreading in the measured efficiencies is greatly reduced. Another practical implication concerns the effect of particle size: although our results confirm the importance of the use of very small particles (
