principles of extraction and the extraction of semivolatile organics ...

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Table 2.4. Distribution Coe‰cient E¤ects on Single and Repeated Extractions Second Sequential Extraction Third Sequential Extraction Single Extraction 1 50 mL 1 50 mL 1 50 mL 2 50 mL 1 50 mL 1 50 mL 3 50 mL Single Extraction 1 150 mL Cumulative Extraction Additional Recovery Repeat Percent Extracted Cumulative Extraction Additional Recovery Repeat Percent Extracted Percent Extracted Percent Extracted Kd 64 500 98.684 96.154 96.154 3.697 99.851 96.154 0.142 99.993 250 97.403 92.593 92.593 6.859 99.451 92.593 0.508 99.959 100 93.750 83.333 83.333 13.890 97.223 83.333 2.315 99.538 50 88.235 71.429 71.429 20.411 91.839 71.429 5.832 97.671 5 42.857 20.000 20.000 16.000 36.000 20.000 12.800 48.800
additional recovery of 3.697% of the original analyte; and the third sequential extraction produces further recovery of 0.142% of the original analyte, for a cumulative recovery after three sequential extractions (3 50 mL) of 99.993%. The cumulative recovery after three extractions of 50 mL each is greater than that calculated for recovery from a single extraction of 150 mL of organic solvent (i.e., 98.684%). The e¤ect of concentration on recovery by single or repeated extractions can be examined. Instead of assuming a concentration of 4:0 10 10 M for the aqueous sample to be extracted as stated in the original problem, the values in Table 2.4 can be recalculated after substitution with a concentration of 0.01 M. If the same four steps outlined previously are followed, it can be demonstrated that the recovery values in Table 2.4 are identical regardless of concentration. The most desirable analytical protocols are independent of sample concentration in the range of samples to be analyzed. The operation conducted in steps 1 through 4 above can be summarized by the following equation such that the recovery factor of analyte X, expressed as a percent, is % RX ¼ 100KD KD þðVO=VEÞ ð2:29Þ where VO is the volume of the original sample and VE is the extraction solvent volume. (Note that the recovery factor is independent of sample concentration.) The recovery factor can also be expressed in the equivalent form % RX ¼ 100 KDðVE=VOÞ 1 þ KDðVE=VOÞ ¼ 100 KDðVÞ 1 þ KDðVÞ ð2:30Þ where V ¼ VE=VO is known as the phase ratio. Therefore, applying equation (2.29) to the previous example in which a 1-L aqueous sample containing 100 ppb of a compound having a molecular weight of 250 g/mol is extracted once with 150 mL of organic extracting solvent, and assuming that KD is 5, substitution yields. 100 5 RX ¼ ¼ 42:857% 5 þð1:0 L=0:150 LÞ If the analyte is partially dissociated in solution and exists as the neutral species, free ions, and ions paired with counterions, the distribution ratio, D, analogous to equation (2.24), would be D ¼ liquid–liquid extraction concentration of X in all chemical forms in the organic phase concentration of X in all chemical forms in the aqueous phase 65 ð2:31Þ
Page 1 and 2: CHAPTER 2 PRINCIPLES OF EXTRACTION
Page 3 and 4: principles of extraction Henry’s
Page 5 and 6: principles of extraction Figure 2.1
Page 7 and 8: principles of extraction Nonvolatil
Page 9 and 10: principles of extraction forces bet
Page 13 and 14: Logarithm of Aqueous Solubility (mm
Page 17 and 18: where KW is the ion product of wate
Page 19 and 20: alpha 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3
Page 21 and 22: liquid-liquid extraction solving ac
Page 23 and 24: Acetone Acetonitrile n-Butyl Alcoho
Page 25 and 26: liquid-liquid extraction Table 2.3.
Page 27: Step 4. Calculate the percent of an
Page 31 and 32: (a) (b) liquid-liquid extraction Fi
Page 33 and 34: liquid-liquid extraction Figure 2.1
Page 35 and 36: Step 1: Adjust aqueous sample to pH
Page 37 and 38: Fujiwara et al. [47] devised instru
Page 39 and 40: liquid-solid extraction centrate se
Page 41 and 42: liquid-solid extraction Macropore R
Page 43 and 44: solid-phase extraction The most com
Page 45 and 46: solid-phase extraction that sample
Page 47 and 48: solid-phase extraction Si O Si Si S
Page 49 and 50: solid-phase extraction meric struct
Page 51 and 52: Si O R Si O H X Si R R Si O X H X H
Page 53 and 54: solid-phase extraction ternary amin
Page 55 and 56: S i l i c a S i l i c a SO 3 − NH
Page 57 and 58: Hydrophobic inner surface solid-pha
Page 59 and 60: Monomer Print molecule Monomer Poly
Page 61 and 62: solid-phase extraction blended laye
Page 63 and 64: solid-phase extraction interact pri
Page 65 and 66: solid-phase extraction ple is a goo
Page 67 and 68: ecovery (%) 120 100 80 60 40 20 sol
Page 69 and 70: solid-phase extraction Reversed Pha
Page 71 and 72: Dependence of Desorption on Eluting
Page 73 and 74: CONDITIONING Conditioning the sorbe
Page 75 and 76: solid-phase extraction Figure 2.45.
Page 77 and 78: solid-phase microextraction 2.4.6.
Page 79 and 80:
solid-phase microextraction KD ¼
Page 81 and 82:
solid-phase microextraction nesses
Page 83 and 84:
solid-phase microextraction Table 2
Page 85 and 86:
Sample Headspace Coating (a) solid-
Page 87 and 88:
Mass [ng] 180 160 140 120 100 80 60
Page 89 and 90:
stir bar sorptive extraction extrac
Page 91 and 92:
Recovery 1 0.9 0.8 0.7 0.6 0.5 0.4
Page 93 and 94:
stir bar sorptive extraction Howeve
Page 95 and 96:
eferences than LLE. The capacity fo
Page 97 and 98:
eferences 26. E. Overton, Studien u
Page 99 and 100:
eferences 69. C. W. Huck and G. K.
Page 101 and 102:
eferences 114. J. Patsias and E. Pa
Page 103 and 104:
CHAPTER 3 EXTRACTION OF SEMIVOLATIL
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introduction [5]. Di¤erent extract
Page 107 and 108:
Porous Thimble Sample soxhlet and a
Page 109 and 110:
ultrasonic extraction for polycycli
Page 111 and 112:
ultrasonic extraction (over 20 ppm)
Page 113 and 114:
pressure S T L G temperature Figure
Page 115 and 116:
Weight % SiO 2 in H 2 O supercritic
Page 117 and 118:
supercritical fluid extraction the
Page 119 and 120:
accelerated solvent extraction for
Page 121 and 122:
Solvent accelerated solvent extract
Page 123 and 124:
Load Cell Fill With Solvent (0.5-1.
Page 125 and 126:
Table 3.9. Solvents Recommended by
Page 127 and 128:
microwave-assisted extraction a qui
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Solvent microwave-assisted extracti
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Cavity Exhausted to Chemical Fume H
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Magnetron microwave-assisted extrac
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microwave-assisted extraction Choic
Page 137 and 138:
comparison of the various extractio
Page 139 and 140:
93-101 1-3 84 1.5- to 2.5-g sample,
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comparison of the various extractio
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eferences 3. Book of ASTM Standards
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eferences 53. A. Hubert, K. Wenzel,
Page 147 and 148:
CHAPTER 4 EXTRACTION OF VOLATILE OR
Page 149 and 150:
Thermometer Screw cap Syringe Rubbe
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static headspace extraction prepara
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Peak area (counts) 12000 10000 8000
Page 155 and 156:
Area A a /A is 16000 14000 12000 10
Page 157 and 158:
static headspace extraction The con
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1. Dichlorodifluoromethane 2. Chlor
Page 161 and 162:
dynamic headspace extraction or pur
Page 163 and 164:
dynamic headspace extraction or pur
Page 165 and 166:
solid-phase microextraction made co
Page 167 and 168:
Coating Material solid-phase microe
Page 169 and 170:
solid-phase microextraction chance
Page 171 and 172:
solid-phase microextraction movemen
Page 173 and 174:
1 liquid-liquid extraction with lar
Page 175 and 176:
liquid-liquid extraction with large
Page 177 and 178:
membrane extraction Feed Side Membr
Page 179 and 180:
membrane extraction cient, C the so
Page 181 and 182:
membrane extraction side volume, wh
Page 183 and 184:
1 2 3 membrane extraction 1. 1,1 Di
Page 185 and 186:
Benzene Toluene membrane extraction
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eferences 4.7. CONCLUSIONS There ar
Page 189:
eferences 38. P. D. Okeyo and N. H.
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