Analytical Chemistry Chemical Cytometry Quantitates Superoxide

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Figure 3. Representative chromatograms of the N1-12-mer [m/z 672 f 223] from MK-2662 plasma sample analyzed using (A) 1D LC-MS/MS or (B) 2D LC-MS/MS. The left panel of part B is the chromatogram from the SCX column (the first dimension), where T18-30 and T19-30 were the peptides obtained from trypsin digestion of MK-2662. The right panel of part B is from the RP column (the second dimension). The total run time for 2D LC-MS/MS was 4.5 min per sample. problem for preparing control plasma in the analysis laboratories. Therefore, a test was conducted to determine equivalence of BD- P700 inhibitor tubes to Linco brand DPP-IV inhibitor that was available in easy to use solution form. The results demonstrated that the stabilizers from BD tubes (1.5 mL of plasma per tube) and Linco inhibitor (20 µL/mL plasma) provided comparable effects in terms of stability (including freeze-thaw, benchtop, autosampler, and reinjection stabilities), matrix effect, and recovery in human plasma. Optimization of Trypsin Digestion Conditions. A surrogate proteolytic peptide approach using trypsin digestion was selected for the MS/MS-based quantification of MK-2662 in human plasma. Following protein precipitation, the supernatant was brought to dryness and then reconstituted in NH 4HCO3 buffer that contained trypsin for digestion. This step needed to be optimized to ensure rapid, complete, and reproducible digest within a reasonable time frame. The digestion yield was tested by varying the amount of trypsin from 2 to 10 µg, the volume of plasma in the BD-P700 tube, and different digestion time at 2, 3, 4, and 16 h in both Linco DPP-IV-containing plasma and the BD-P700-treated plasma, where the latter appeared to need more trypsin due to the inhibitory effect of proprietary enzyme inhibitors. The reason for testing plasma volume was that, at the clinical site, although 3 mL of blood per sample was required in BD tube, there was a chance that less volume was collected. Since the BD tubes contain a fixed amount of protease inhibitor, the lower the blood volume, the higher the inhibitor concentration in the tube, which may lead to the more difficult trypsin digestion. 6882 <strong>Analytical</strong> <strong>Chemistry</strong>, Vol. 82, No. 16, August 15, 2010 The tested plasma volume at 1 and 1.5 mL covered a range of 2-3 mL of blood collection. The test results are shown in Figure S2 (see the Supporting Information), where the experiment was conducted at 10 nM MK- 2662 in all samples, and the yield was calculated assuming 100% digestion in a neat MK-2662 solution incubated with trypsin for 3 h. The spiked plasma without inhibitor appeared to give higher yield compared to the neat sample, presumably due to surface absorption loss of the neat sample. The data indicated that a digestion with 7 µg of trypsin was very sensitive to the change of blood volumes1 mL of plasma (equivalent to 2 mL of blood collection) required much longer digestion time to achieve >80% digestion. In contrast, a digestion with 10 µg of trypsin demonstrated an improved tolerability, yielding nearly complete digestion within 3-4 h for both 1 and 1.5 mL of plasma (equivalent to 2-3 mL of blood collected in the BD-P700 tube). Balancing the benefit and risk by considering digestion yield and sample processing time, the digestion conditions10 µg of trypsin for 3 hswas selected. The digestion outcome under these conditions was robust and highly reproducible. Consequently, the clinical site was instructed to collect 3 mL of blood (1.5 mL plasma equivalent) and to record significant deviation from this volume. Solvent for Working Standard Solutions. It is well-known that peptides are prone to absorption loss to container surfaces. 9 Initially, 30% acetonitrile was used for preparation of both primary stock and working standard solutions. Following storage at 4 °C for 3 weeks, the primary stock was stable; however, more than 30% of MK-2662 loss was observed in working stock solutions. Switching the working stock solvent to 1% BSA and storing at
-70 °C resolved the problem, giving
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Anal. Chem. 2010, 82, 6745-6750 Let
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purchased from Invitrogen-Molecular
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Figure 3. Electropherograms of TPP-
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Anal. Chem. 2010, 82, 6751-6755 Res
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(pH 8.0) with cysteine and cystamin
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Figure 4. Ion mobility mass spectra
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GOx glucose + O298 gluconic acid +
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coater at 2000 rpm for 20 s, and th
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Figure 5. Comparison of cyclic volt
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in channels with either no grooves
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indicators of atmospheric processin
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Figure 1. GC/MS total ion chromatog
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Table 2. Concentrations and Stable
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on a substrate are preferred. 20-24
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Figure 4. SERS analysis of NAADP co
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Anal. Chem. 2010, 82, 6775-6781 Hig
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tion, 2 µL of proprionaldehyde wer
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Figure 4. Analysis of 2a by HPLC-MS
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eaction of 1a with PBH can be condu
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Numerous references had demonstrate
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Figure 1. TEM images of the prepare
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Figure 4. Schematic representation
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esult in a big SPR signal change wi
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also reduces chemical noise, which
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Table 1. Extraction Yields, Liquid
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scanning of AMPP amides of the anal
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Anal. Chem. 2010, 82, 6797-6806 δ
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Figure 1. Schematic view of the pre
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from the specimen and enclosed in a
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Figure 4. (A) IRMS mass-44 chromato
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Table 3. Ambient Measurement Result
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Anal. Chem. 2010, 82, 6807-6813 Dir
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Polymerase (1 U per sample). Reacti
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of which was constant for all ampli
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analytically useful signals at less
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carbon black and RP-C18 for the ext
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solution in an equal volume, and 1
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Table 2. Concentrations and Ratios
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Anal. Chem. 2010, 82, 6821-6829 Mac
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mg/mL protein, followed by separati
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Figure 2. Productivity of SEQUST an
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Figure 4. High-resolution MS/MS spe
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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 and 108: Table 1. Counting Properties and De
Page 109 and 110: Table 3. Analysis of 226 Ra in Sedi
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: Figure 2. Product ion mass spectra
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
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Anal. Chem. 2010, 82, 6933-6939 Dif
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trode 28 by a finite element using
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Figure 4. Comparison between simula
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Figure 6. Comparison between simula
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educed in the vicinity of double bo
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Figure 2. Normalized product ion ab
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Figure 4. EID (a) and IRMPD (b) of
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Anal. Chem. 2010, 82, 6947-6957 Ide
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Figure 1. Schematic flowchart showi
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difference, ppm compound Table 1. I
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isoforms, its successful use, in th
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Figure 5. Extracted ion current ESI
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m/z 1172.935 was observed for Ser14
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linked products via affinity tags.
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Scheme 2. Fragmentation Mechanism o
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Figure 1. (A) ESI-LTQ-CID-MS 2 prod
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Figure 3. (A) ESI-LTQ-CID-MS 2 prod
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Figure 5. (A) MALDI-TOF/TOF product
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Anal. Chem. 2010, 82, 6969-6975 Ana
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Figure 3. Equilibrium response as a
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Figure 6. The average measured resp
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for the fill time, and we find that
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nucleotide tails. 3-5 Thus, the amo
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allow the use of higher aptamer con
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quent ligation of the aptamers afte
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Anal. Chem. 2010, 82, 6983-6990 Imp
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Figure 2. Configuration editor wind
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Figure 4. Dependencies between volu
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Since the time for liquid expulsion
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Anal. Chem. 2010, 82, 6991-6999 Int
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Figure 1. Representation of the Car
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Table 2. Capillary Electrophoresis
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Figure 4. (A) Typical raw electroph
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field. DNA profiles were delivered
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Another approach to handle this lim
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(principal components, PCs) in whic
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Figure 5. Relevant score plots and
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CONCLUSIONS In this paper we have i
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electroactive-species loaded liposo
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Figure 2. Qdot-based FLFTS response
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Figure 6. Fluorescence imaging of Q
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Anal. Chem. 2010, 82, 7015-7020 Sel
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Table 1. Effect of 1 D-LC Condition
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Figure 3. Peak-production rate vers
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Anal. Chem. 2010, 82, 7021-7026 Cel
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luciferase (T7 control vector) was
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Figure 3. Inhibitory effects of luc
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Anal. Chem. 2010, 82, 7027-7034 Pat
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Electrochemistry. Electrochemical m
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Figure 2. SEM images of Au substrat
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Table 3. Film Thickness Measurement
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Anal. Chem. 2010, 82, 7035-7043 Qua
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Figure 1. (A) FL spectra of BSPOTPE
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Figure 4. (A) Variation in the FL i
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Figure 6. (A) FL spectra of BSPOTPE
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Scheme 1. Proposed Mechanism for Fl
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one or more drawbacks including poo
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Figure 2. Free fluorophores do not
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Anal. Chem. 2010, 82, 7049-7052 Dev
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Figure 2. Comparative analysis of d
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