Analytical Chemistry Chemical Cytometry Quantitates Superoxide

More documents

Recommendations

Info

activities ranging over 2 orders of magnitude, all yielding satisfactory results (Table 3). The IAEA-384, a Fangataufa Lagoon sediment, is a reference material designed for the determination of anthropogenic and natural radionuclides in sediment. 27 This material is certified for 10 radionuclides, including 210Pb ( 210Po in equilibrium), and information values are given for 10 radionuclides, including 226 226 -1 Ra. The Ra activity ranges from 2.0 to 2.9 Bq kg (95% confidence interval) with a median value of 2.4 Bq kg-1 , which is the low range of 226Ra activities in sediments. Dry sediment aliquots of 500 mg were analyzed by using the proposed method (N ) 15). Spectra were analyzed by using both a wide and a narrow counting window, and results are shown in Figure 9. The median of both distributions is 2.2 Bq kg-1 , and means were 2.3 Bq kg-1 (50 channels) and 2.5 Bq kg-1 (150 channels), very close to the reference material reported value and within its 95% confidence interval. The IAEA-385, a certified reference material for radionuclides in an Irish Sea sediment, is intended to be used, among other purposes, for the development and validation of radiometric and mass spectrometry analytical methods. 28 Its certified median value, 22.7 Bq kg-1 , is typical of most soils and sediments. The median value obtained with the proposed method (N ) 15) is 23.5 Bq kg-1 Figure 8. Calibration curve of unquenched , which, although slightly higher than the upper limit of the certified confidence interval, represents a deviation of only 7.3%. 226Ra. (27) Povinec, P. P.; Pham, M. K.; Sanchez-Cabeza, J. A.; Barci-Funel, G.; Bojanawski, R.; Boshkova, T.; Burnett, W.; Carvalho, F.; Chapeyron, B.; Cunha, I. L.; Dahlgaard, H.; Galabov, N.; Fifield, L.; Gaustaud, J.; Geering, J.-J.; Gomez, I. F.; Green, N.; Hamilton, T.; Ibanez, F. L.; Ibn Majah, M.; John, M.; Kanisch, G.; Kenna, T. C.; Kloster, M.; Korun, M.; Liong Wee Kwong, L.; La Rosa, J.; Lee, S.-H.; Levy-Plaomo, I.; Malatova, M.; Maruo, Y.; Michell, P.; Murciano, I. V.; Nelson, R.; Nouredine, A.; Oh, J.-S.; Oregioni, B.; Petit, G.; Pettersson, H. B. L.; Reineking, A.; Smedley, P. A.; Suckow, A.; Struijs, T.; Voors, P. I.; Yoshimiza, K.; Wyse, E. J. Radioanal. Nucl. Chem. 2007, 273, 383–393. (28) Pham, M. K.; Sanchez-Cabeza, J. A.; Povinec, P. P.; Andor, K.; Arnold, D.; Benmansour, M.; Bikit, I.; Carvalho, F. P.; Dimitrova, K.; Edrev, Z. H.; Engeler, C.; Fouche, F. J.; Garcia-Orellana, J.; Gascó, C.; Gastaud, J.; Gudelis, A.; Hancock, G.; Holm, E.; Legarda, F.; Ikäheimonen, T. K.; Ilchmann, C.; Jenkinson, A. V.; Kanisch, G.; Kis-Benedek, G.; Kleinschmidt, R.; Koukouliou, V.; Kuhar, B.; LaRosa, J.; Lee, S.-H.; LePetit, G.; Levy-Palomo, I.; Liong Wee Kwong, L.; Llauradó, M.; Maringer, F. J.; Meyer, M.; Michalik, B.; Michel, H.; Nies, H.; Nour, S.; Oh, J.-S.; Oregioni, B.; Palomares, J.; Pantelic, G.; Pfitzner, J.; Pilviok, R.; Puskeiler, L.; Satake, H.; Schikowski, J.; Vitorovic, G.; Woodhead, D.; Wyse, E. Appl. Radiat. Isot. 2008, 66, 1711– 1717. 6852 Analytical Chemistry, Vol. 82, No. 16, August 15, 2010 The IAEA-313, a stream sediment from Indonesia, 29 is a reference material designed for the analysis of 226Ra, U, and Th in geological samples. Its median 226Ra activity, 343 Bq kg-1 , is about 1 order of magnitude higher than typical sediment activities. The median value (N ) 5) is within the reported 95% confidence interval. The observed deviations are typical of the precision of environmental materials, and in overall, we concluded that the proposed method is adequate to analyze 226Ra in sediment samples. Calibration Stability. With each sample batch, we have analyzed the IAEA-384 reference material for quality control purposes. Results of all analyses are shown in Figure 10. The mean value, 2.3 Bq kg-1 , lies within the reference material 95% confidence interval (Table 3), and the time stability of the activity shows that the system’s calibration is stable for times spanning at least during the measurement period, namely, one year. Although this needs to be checked for each instrument in a continuous manner, we do not anticipate the need of recalibration of Quantulus 1220 for periods shorter than a year. 210 226 Pb and Ra in a Sediment Core. The method is designed to provide fast and reliable results of 226Ra when 210Pb dating sediment cores through the analysis of 210Po in equilibrium. The advantage of LSC over γ spectrometry is that results for a large number of samples, typical of 210Pb dating experiments, can be obtained within a month after sample digestion. We provide here an example of the proposed strategy. The DYFAMED station (Ligurian Sea, 43°25′ N; 7°52′ E) has been the subject of multidisciplinary research since 1987, including the study of atmospheric deposition of metals and their association with marine particles in the water column. Martín et al. 30 studied the concentrations and fluxes of trace metals in a sediment core collected from 2300 m water depth at the sea floor beneath the DYFAMED site. In Figure 11, we show the 210Pb and 226 Figure 9. Box-and-whisker plots of Ra profiles obtained by R spectrometry and LSC, showing that 226Ra activities in the reference material IAEA-384 (N ) 15). The two dots in the 50 channels counting window were statistically identified as outliers. (29) Strachnov, V.; Valkovic, V.; Zeisler, R.; Dekner, R. Report on the Worldwide Intercomparison Exercise IAEA-314: 226 Ra, Th and U in Stream Sediment; International Atomic Energy Agency (IAEA/AL/038): Vienna, Austria, 1991. (30) Martin, J.; Sanchez-Cabeza, J. A.; Eriksson, M.; Miquel, J. C. Mar. Pollut. Bull. 2009, 59, 146–153.
Table 3. Analysis of 226 Ra in Sediment Reference Materials (RM) reference material no. of analyses method median (Bq kg-1 ) RM median (Bq kg-1 ) RM 95% confidence interval deviation IAEA-384 15 2.2 2.4 2.0–2.9 -8.3 IAEA-385 15 23.5 21.9 21.6–22.4 +7.3 IAEA-313 5 372 343 307–379 +8.5 Figure 10. Time stability test for 226 Ra concentrations in the IAEA- 384 reference material. 226Ra reaches equilibrium in the core bottom sections. An important finding was that, although a constant 226Ra is commonly estimated from core bottom sections, where 210Pb and 226Ra are assumed to be in equilibrium, this is not the case in the DYFAMED core, where 226Ra ranged from 22.6 to 41.7 Bq kg-1 . This reinforces the need for paired 210Pb/ 226 Figure 11. Ra 210Pb and 226Ra profiles in a sediment core from the DYFAMED site (Ligurian Sea). measurements and methodologies to accomplish it accurately, as does the technique described in this paper. This may have important implications on the dating results for this particular sediment core, which will be discussed elsewhere. CONCLUSIONS The accurate 210 Pb dating of sediment cores requires the determination of 226 Ra in all sections. Although this can be done by γ spectrometry, the large sample size required (>5 g dry weight in well detectors, >20 g in coaxial detectors) might be impossible to obtain when sediments are used for the analysis of multiple magnitudes (such as grain size, elemental composition, trace metals, organic substances, biomarkers, ...) and counting times (typically >2 days per sample) might be a limiting factor for many laboratories. The proposed strategy in this work is the determination of 210 Pb through 210 Po in equilibrium by R spectrometry 10 followed by 226 Ra by LSC without any further radiochemical processing. We optimized the counting parameters for an ultralow background scintillation system with R-� separation capabilities (Quantulus 1220, Wallac) and propose the use of a PSA parameter of 145. The system was calibrated with a series of quenched 226 Ra standard solutions. For a typical sediment sample quenching (SQP(E) ) 850), the efficiency was (173 ± 12)% in the wide energy counting window (150 channels) due to the simultaneous counting of three radionuclides in equilibrium ( 222 Rn, 218 Po, and 214 Po). When analyzing 250 mg dw sediment samples, the MDA was as low as 0.29 Bq kg -1 , which is about 2 orders of magnitude lower than typical sediment concentrations, showing the usefulness of the technique for many other environmental applications. The method was validated with three reference materials spanning 3 orders of magnitude of concentration. The proposed method can greatly improve the reliability of 210 Pb chronologies of sediment cores, and can also be tested for 226 Ra/ 210 Pb dating of carbonates such as corals and speleothems. ACKNOWLEDGMENT The authors thank Mr. Jacobo Martín (IAEA) for providing samples of a sediment core from the DYFAMED site and helpful comments. The IAEA is grateful for the support provided to its Marine Environment Laboratories by the Government of the Principality of Monaco. Received for review March 31, 2010. Accepted June 30, 2010. AC1008332 Analytical Chemistry, Vol. 82, No. 16, August 15, 2010 6853
Page 1 and 2:
Anal. Chem. 2010, 82, 6745-6750 Let
Page 3 and 4:
purchased from Invitrogen-Molecular
Page 5 and 6:
Figure 3. Electropherograms of TPP-
Page 7 and 8:
Anal. Chem. 2010, 82, 6751-6755 Res
Page 9 and 10:
(pH 8.0) with cysteine and cystamin
Page 11 and 12:
Figure 4. Ion mobility mass spectra
Page 13 and 14:
GOx glucose + O298 gluconic acid +
Page 15 and 16:
coater at 2000 rpm for 20 s, and th
Page 17 and 18:
Figure 5. Comparison of cyclic volt
Page 19 and 20:
in channels with either no grooves
Page 21 and 22:
indicators of atmospheric processin
Page 23 and 24:
Figure 1. GC/MS total ion chromatog
Page 25 and 26:
Table 2. Concentrations and Stable
Page 27 and 28:
on a substrate are preferred. 20-24
Page 29 and 30:
Figure 4. SERS analysis of NAADP co
Page 31 and 32:
Anal. Chem. 2010, 82, 6775-6781 Hig
Page 33 and 34:
tion, 2 µL of proprionaldehyde wer
Page 35 and 36:
Figure 4. Analysis of 2a by HPLC-MS
Page 37 and 38:
eaction of 1a with PBH can be condu
Page 39 and 40:
Numerous references had demonstrate
Page 41 and 42:
Figure 1. TEM images of the prepare
Page 43 and 44:
Figure 4. Schematic representation
Page 45 and 46:
esult in a big SPR signal change wi
Page 47 and 48:
also reduces chemical noise, which
Page 49 and 50:
Table 1. Extraction Yields, Liquid
Page 51 and 52:
scanning of AMPP amides of the anal
Page 53 and 54:
Anal. Chem. 2010, 82, 6797-6806 δ
Page 55 and 56:
Figure 1. Schematic view of the pre
Page 57 and 58: from the specimen and enclosed in a
Page 59 and 60: Figure 4. (A) IRMS mass-44 chromato
Page 61 and 62: Table 3. Ambient Measurement Result
Page 63 and 64: Anal. Chem. 2010, 82, 6807-6813 Dir
Page 65 and 66: Polymerase (1 U per sample). Reacti
Page 67 and 68: of which was constant for all ampli
Page 69 and 70: analytically useful signals at less
Page 71 and 72: carbon black and RP-C18 for the ext
Page 73 and 74: solution in an equal volume, and 1
Page 75 and 76: Table 2. Concentrations and Ratios
Page 77 and 78: Anal. Chem. 2010, 82, 6821-6829 Mac
Page 79 and 80: mg/mL protein, followed by separati
Page 81 and 82: Figure 2. Productivity of SEQUST an
Page 83 and 84: Figure 4. High-resolution MS/MS spe
Page 85 and 86: Figure 6. Characterization of PSMs
Page 87 and 88: containing T-T mismatches. 23 Based
Page 89 and 90: Figure 1. Extinction spectra of sol
Page 91 and 92: Figure 3. (A) The value of Ex650 nm
Page 93 and 94: Figure 5. Extinction spectra and co
Page 95 and 96: wished to explore the dehydration o
Page 97 and 98: constant medium for separation; we
Page 99 and 100: Figure 2. Standards of (Pi)n, n ) 1
Page 101 and 102: Figure 5. Quantitative calibration
Page 103 and 104: Anal. Chem. 2010, 82, 6847-6853 Met
Page 105 and 106: Figure 1. 226 Ra spectrum by liquid
Page 107: Table 1. Counting Properties and De
Page 111 and 112: mercial microarray scanner and fabr
Page 113 and 114: Figure 2. Optical transmission meas
Page 115 and 116: Figure 5. Volcano plots detailing t
Page 117 and 118: data as well. The 41 genes in Table
Page 119 and 120: corresponding compound if its chemi
Page 121 and 122: Figure 1. Schematic illustration of
Page 123 and 124: Table 1. Absolute Quantification Re
Page 125 and 126: ment. Therefore, the long-time drea
Page 127 and 128: Figure 1. Chemically actuated micro
Page 129 and 130: Figure 2. Influence of a surfactant
Page 131 and 132: Figure 5. Device to eject and mix s
Page 133 and 134: Anal. Chem. 2010, 82, 6877-6886 Imm
Page 135 and 136: NaCl, phosphate buffer saline (PBS)
Page 137 and 138: Figure 2. Product ion mass spectra
Page 139 and 140: -70 °C resolved the problem, givin
Page 141 and 142: Table 1. Intraday Precision and Acc
Page 143 and 144: Anal. Chem. 2010, 82, 6887-6894 Fer
Page 145 and 146: Figure 1. Infrared spectra of (A) u
Page 147 and 148: Figure 3. Cyclic voltammograms obta
Page 149 and 150: Figure 6. Calculated charge from ch
Page 151 and 152: Anal. Chem. 2010, 82, 6895-6903 Ele
Page 153 and 154: Table 1. Chemical Structure, pKa Va
Page 155 and 156: pH with a tilted baseline (Figure 1
Page 157 and 158: Table 2. Linearity and Detection Li
Page 159 and 160:
ascorbic acid (AA), uric acid (UA),
Page 161 and 162:
the multielement capabilities, the
Page 163 and 164:
RESULTS AND DISCUSSION Sulfur Detec
Page 165 and 166:
Table 2. Molecular Properties and C
Page 167 and 168:
Anal. Chem. 2010, 82, 6911-6918 Dir
Page 169 and 170:
dilution and hybridization buffer.
Page 171 and 172:
solution under appropriate incubati
Page 173 and 174:
Figure 4. Standardization curve for
Page 175 and 176:
Anal. Chem. 2010, 82, 6919-6925 Ele
Page 177 and 178:
the ×10 objective, to have a large
Page 179 and 180:
Figure 2. With a suitable removal o
Page 181 and 182:
the NB signal in a much better foot
Page 183 and 184:
Scheme 1. Reactions of Selenium Rea
Page 185 and 186:
Figure 2. (a) ESI-MS spectrum showi
Page 187 and 188:
Figure 4. (a) ESI-MS spectrum showi
Page 189 and 190:
Anal. Chem. 2010, 82, 6933-6939 Dif
Page 191 and 192:
trode 28 by a finite element using
Page 193 and 194:
Figure 4. Comparison between simula
Page 195 and 196:
Figure 6. Comparison between simula
Page 197 and 198:
educed in the vicinity of double bo
Page 199 and 200:
Figure 2. Normalized product ion ab
Page 201 and 202:
Figure 4. EID (a) and IRMPD (b) of
Page 203 and 204:
Anal. Chem. 2010, 82, 6947-6957 Ide
Page 205 and 206:
Figure 1. Schematic flowchart showi
Page 207 and 208:
difference, ppm compound Table 1. I
Page 209 and 210:
isoforms, its successful use, in th
Page 211 and 212:
Figure 5. Extracted ion current ESI
Page 213 and 214:
m/z 1172.935 was observed for Ser14
Page 215 and 216:
linked products via affinity tags.
Page 217 and 218:
Scheme 2. Fragmentation Mechanism o
Page 219 and 220:
Figure 1. (A) ESI-LTQ-CID-MS 2 prod
Page 221 and 222:
Figure 3. (A) ESI-LTQ-CID-MS 2 prod
Page 223 and 224:
Figure 5. (A) MALDI-TOF/TOF product
Page 225 and 226:
Anal. Chem. 2010, 82, 6969-6975 Ana
Page 227 and 228:
Figure 3. Equilibrium response as a
Page 229 and 230:
Figure 6. The average measured resp
Page 231 and 232:
for the fill time, and we find that
Page 233 and 234:
nucleotide tails. 3-5 Thus, the amo
Page 235 and 236:
allow the use of higher aptamer con
Page 237 and 238:
quent ligation of the aptamers afte
Page 239 and 240:
Anal. Chem. 2010, 82, 6983-6990 Imp
Page 241 and 242:
Figure 2. Configuration editor wind
Page 243 and 244:
Figure 4. Dependencies between volu
Page 245 and 246:
Since the time for liquid expulsion
Page 247 and 248:
Anal. Chem. 2010, 82, 6991-6999 Int
Page 249 and 250:
Figure 1. Representation of the Car
Page 251 and 252:
Table 2. Capillary Electrophoresis
Page 253 and 254:
Figure 4. (A) Typical raw electroph
Page 255 and 256:
field. DNA profiles were delivered
Page 257 and 258:
Another approach to handle this lim
Page 259 and 260:
(principal components, PCs) in whic
Page 261 and 262:
Figure 5. Relevant score plots and
Page 263 and 264:
CONCLUSIONS In this paper we have i
Page 265 and 266:
electroactive-species loaded liposo
Page 267 and 268:
Figure 2. Qdot-based FLFTS response
Page 269 and 270:
Figure 6. Fluorescence imaging of Q
Page 271 and 272:
Anal. Chem. 2010, 82, 7015-7020 Sel
Page 273 and 274:
Table 1. Effect of 1 D-LC Condition
Page 275 and 276:
Figure 3. Peak-production rate vers
Page 277 and 278:
Anal. Chem. 2010, 82, 7021-7026 Cel
Page 279 and 280:
luciferase (T7 control vector) was
Page 281 and 282:
Figure 3. Inhibitory effects of luc
Page 283 and 284:
Anal. Chem. 2010, 82, 7027-7034 Pat
Page 285 and 286:
Electrochemistry. Electrochemical m
Page 287 and 288:
Figure 2. SEM images of Au substrat
Page 289 and 290:
Table 3. Film Thickness Measurement
Page 291 and 292:
Anal. Chem. 2010, 82, 7035-7043 Qua
Page 293 and 294:
Figure 1. (A) FL spectra of BSPOTPE
Page 295 and 296:
Figure 4. (A) Variation in the FL i
Page 297 and 298:
Figure 6. (A) FL spectra of BSPOTPE
Page 299 and 300:
Scheme 1. Proposed Mechanism for Fl
Page 301 and 302:
one or more drawbacks including poo
Page 303 and 304:
Figure 2. Free fluorophores do not
Page 305 and 306:
Anal. Chem. 2010, 82, 7049-7052 Dev
Page 307 and 308:
Figure 2. Comparative analysis of d
show all

Analytical Chemistry Chemical Cytometry Quantitates Superoxide

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?