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*Description of Method.* The amount of chlorpromazine in a pharmaceutical formulation is determined voltammetrically at a graphite working electrode in a nonstirred solution. Calibration is achieved using the method of standard additions.
*Procedure.* Place 10.00 mL of a solution consisting of 0.01 M HCl and 0.1 M KC... | {
"Header 1": "**Method 11.3 Determination of Chlorpromazine25**",
"token_count": 1977,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Solving equation 11.42 for $[O]_{x=0}$ and substituting into the Nernst equation gives
$$E = E_{\text{O/R}}^{\circ} - \frac{0.05916}{n} \log \frac{[R]_{x=0} [L]_{x=0}^{p} \beta_{p}}{[\text{OL}_{p}]_{x=0}}$$
11.44
If the ligand is present in excess and the formation constant is sufficiently large, such that all of... | {
"Header 1": "**Method 11.3 Determination of Chlorpromazine25**",
"token_count": 441,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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A voltammogram for the two-electron reduction of M has a half-wave potential of −0.226 V versus the SCE. In the presence of an excess of the ligand L, the following half-wave potentials are recorded
| [L]<br>(M) | (E1/2)c<br>(V vs. SCE) |
|------------|------------------------|
| 0.020 | –0.494 |... | {
"Header 1": "**EXAMPLE 11.14**",
"token_count": 515,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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**Scale of Operation** Voltammetry is routinely used to analyze samples at the parts-per-million level and, in some cases, can be used to detect analytes at the parts-per-billion or parts-per-trillion level. Most analyses are carried out in conventional electrochemical cells using macro samples; however, microcells are... | {
"Header 1": "**11D.8 Evaluation**",
"token_count": 1231,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Electrochemical methods covered in this chapter include potentiometry, coulometry, and voltammetry. Potentiometric methods are based on the measurement of an electrochemical cell's potential when only a negligible current is allowed to flow. In principle the Nernst equation can be used to calculate the concentration of... | {
"Header 1": "**11F SUMMARY**",
"token_count": 1017,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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*The following set of suggested experiments describes the preparation of solid-state and liquid ion-exchange ionselective electrodes, as well as potentiometric biosensors.*
Chan, W. H.; Wong, M. S.; Yip, C. W. "Ion-Selective Electrode in Organic Analysis: A Salicylate Electrode," *J. Chem. Educ.* **1986,** *63,* 915–... | {
"Header 1": "**11G** *Suggested* **EXPERIMENTS**",
"token_count": 2049,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Iodide is determined by titrating with coulometrically generated Br2. Chloride is determined indirectly by the coulometric titration of H+. Finally, iodide and chloride are determined together by precipitating AgI and AgCl following the anodic dissolution of an Ag wire.
Swim, J.; Earps, E.; Reed, L. M.; et al. "Const... | {
"Header 1": "**11G** *Suggested* **EXPERIMENTS**",
"token_count": 1030,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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#### **IIH PROBLEMS**
- **1.** Identify the anode and cathode for the following electrochemical cells, and write the oxidation or reduction reaction occurring at each electrode.
- (a) Pt | FeCl $_2$ (0.015 M), FeCl $_3$ (0.045 M) || AgNO $_3$ (0.1 M) | Ag
- (b) Ag | AgBr(s) | NaBr (1.0 M) || CdCl<sub>2</sub> (0.05... | {
"Header 1": "30",
"token_count": 1927,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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| | Potential<br>(mV) | |
|---------|-------------------------------------|-----------------------------------------------------------------------|
| Trial 1 | Trial 2 | Trial 3 ... | {
"Header 1": "30",
"token_count": 2049,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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The limiting current for the sample was found to be 444 µA. Report the purity of this sample of K3Fe(CN)6.
- **22.** Anodic stripping voltammetry at a mercury film electrode can be used to determine whether an individual has recently fired a gun by looking for traces of antimony in residue collected from the individu... | {
"Header 1": "30",
"token_count": 2044,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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A second portion of the filtered solution is irradiated with UV light, and the concentrations of ASV metal and total metal are measured. Finally, a third portion of the filtered solution is irradiated with UV light, passed through an ion-exchange column, and the concentrations of ASV-labile metal and total metal are ag... | {
"Header 1": "30",
"token_count": 1823,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The following general references provide a broad introduction to electrochemical methods of analysis.
Bard, A. J.; Faulkner, L. R. *Electrochemical Methods.* Wiley: New York, 1980.
Faulkner, L. R. "Electrochemical Characterization of Chemical Systems." In Kuwana, T. E., ed., *Physical Methods in Modern Chemical Ana... | {
"Header 1": "**11I SUGGESTED READINGS**",
"token_count": 1550,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
- 1. Stork, J. T. *Anal. Chem.* **1993,** *65,* 344A–351A.
- 2. Sawyer, D. T.; Roberts, J. L., Jr. *Experimental Electrochemistry for Chemists.* Wiley-Interscience: New York, 1974, p. 22.
- 3. Cammann, K. *Working with Ion-Selective Electrodes.* Springer-Verlag: Berlin, 1977.
- 4. (a) Papastathopoulos, D. S.; Rechnitz,... | {
"Header 1": "**11J REFERENCES**",
"token_count": 1175,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
- *Laboratory Techniques in Electroanalytical Chemistry.* Marcel Dekker, Inc.: New York, 1984, pp. 569–607.
- 24. Cammann, K.; Lemke, U.; Rohen, A.; et al. *Angew. Chem. Int. Ed. Engl.* **1991,** *30,* 516–539.
- 25. Procedure adapted from Pungor, E. *A Practical Guide to Instrumental Analysis.* CRC Press: Boca Raton, ... | {
"Header 1": "**11J REFERENCES**",
"Header 3": "**542** Modern Analytical Chemistry",
"token_count": 680,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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In Chapter 7 we examined several methods for separating an analyte from potential interferents. For example, in a liquid–liquid extraction the analyte and interferent are initially present in a single liquid phase. A second, immiscible liquid phase is introduced, and the two phases are thoroughly mixed by shaking. Duri... | {
"Header 1": "12A Overview of Analytical Separations",
"token_count": 1574,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Analytical separations may be classified in three ways: by the physical state of the mobile phase and stationary phase; by the method of contact between the mobile phase and stationary phase; or by the chemical or physical mechanism responsible for separating the sample's constituents. The mobile phase is usually a liq... | {
"Header 1": "**12A.3 Classifying Analytical Separations**",
"token_count": 584,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Of the two methods for bringing the stationary and mobile phases into contact, the more important is column chromatography. In this section we develop a general theory that we may apply to any form of column chromatography. With appropriate modifications, this theory also can be applied to planar chromatography.
A ty... | {
"Header 1": "**12B General Theory of Column Chromatography**",
"token_count": 2041,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Rearranging and solving for the fraction of solute in the mobile phase, $f_{\rm m}$ , gives
$$f_{\rm m} = \frac{(\text{moles S})_{\rm m}}{(\text{moles S})_{\rm tot}} = \frac{V_{\rm m}}{V_{\rm m} + DV_{\rm s}}$$
12.4
Note that this equation is identical to that describing the extraction of a solute in a liquid–liqu... | {
"Header 1": "**12B General Theory of Column Chromatography**",
"token_count": 814,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The relative selectivity of a chromatographic column for a pair of solutes is given by the **selectivity factor**, $\alpha$ , which is defined as
$$\alpha = \frac{k_{\rm B}'}{k_{\rm A}'} = \frac{t_{\rm r,B} - t_{\rm m}}{t_{\rm r,A} - t_{\rm m}}$$
12.11
The identities of the solutes are defined such that solute A a... | {
"Header 1": "12B.3 Column Selectivity",
"token_count": 422,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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At the beginning of a chromatographic separation the solute occupies a narrow band of finite width. As the solute passes through the column, the width of its band continually increases in a process called **band broadening**. Column efficiency provides a quantitative measure of the extent of band broadening.
In their... | {
"Header 1": "12B.4 Column Efficiency",
"token_count": 991,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Another important consideration is the number of solutes that can be baseline resolved on a given column. An estimate of a column's **peak capacity**, $n_C$ is
$$n_{\rm c} = 1 + \frac{\sqrt{N}}{4} \ln \frac{V_{\rm max}}{V_{\rm min}}$$
12.18
where $V_{\min}$ and $V_{\max}$ are the smallest and largest volumes ... | {
"Header 1": "12B.5 Peak Capacity",
"token_count": 466,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The treatment of chromatography outlined in Section 12B assumes that a solute elutes as a symmetrical band, such as that shown in Figure 12.7. This ideal behavior occurs when the solute's partition coefficient, *K*D, is constant for all concentrations of solute. In some situations, chromatographic peaks show nonideal b... | {
"Header 1": "**12B.6 Nonideal Behavior**",
"token_count": 224,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Now that we have defined capacity factor, selectivity, and column efficiency we consider their relationship to chromatographic resolution. Since we are only interested in the resolution between solutes eluting with similar retention times, it is safe to assume that the peak widths for the two solutes are approximately ... | {
"Header 1": "**I2C** Optimizing Chromatographic Separations",
"token_count": 1694,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
A second approach to improving resolution is to adjust alpha, α. In fact, when α is nearly 1, it usually is not possible to improve resolution by adjusting *k*B′ or *N.* Changes in α often have a more dramatic effect on resolution than *k*B′. For example, changing α from 1.1 to 1.5 improves resolution by 267%.
A chan... | {
"Header 1": "**12C.2 Using Column Selectivity to Optimize Resolution**",
"token_count": 320,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
If the capacity factor and α are known, then equation 12.21 can be used to calculate the number of theoretical plates needed to achieve a desired resolution (Table 12.1). For example, given α = 1.05 and *k*B′ = 2.0, a resolution of 1.25 requires approximately 24,800 theoretical plates. If the column only provides 12,40... | {
"Header 1": "**12C.3 Using Column Efficiency to Optimize Resolution**",
"token_count": 1949,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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**Putting It All Together** The net height of a theoretical plate is a summation of the contributions from each of the terms in equations 12.23–12.26; thus,
$$H = H_{p} + H_{d} + H_{s} + H_{m}$$
12.27
An alternative form of this equation is the van Deemter equation
$$H = A + \frac{B}{u} + Cu$$
12.28
which emp... | {
"Header 1": "**12C.3 Using Column Efficiency to Optimize Resolution**",
"token_count": 1081,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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The most common mobile phases for GC are He, Ar, and N2, which have the advantage of being chemically inert toward both the sample and the stationary phase. The choice of which carrier gas to use is often determined by the instrument's detector. With packed columns the mobile-phase velocity is usually within the range ... | {
"Header 1": "**12D.1 Mobile Phase**",
"token_count": 1317,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Selectivity in gas chromatography is influenced by the choice of stationary phase. Elution order in GLC is determined primarily by the solute's boiling point and, to a lesser degree, by the solute's interaction with the stationary phase. Solutes with significantly different boiling points are easily separated. On the o... | {
"Header 1": "**12D.3 Stationary Phases**",
"token_count": 2045,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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To maintain efficiency the solutes often are concentrated at the top of the column by cooling the column inlet below room temperature, a process known as **cryogenic focusing.**
Nonvolatile analytes must be chemically converted to a volatile derivative before analysis. For example, amino acids are not sufficiently vo... | {
"Header 1": "**12D.3 Stationary Phases**",
"token_count": 611,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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The final part of a gas chromatograph is the detector. The ideal detector has several desirable features, including low detection limits, a linear response over a wide range of solute concentrations (which makes quantitative work easier), responsiveness to all solutes or selectivity for a specific class of solutes, and... | {
"Header 1": "**12D.6 Detectors for Gas Chromatography**",
"token_count": 1595,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Gas chromatography is widely used for the analysis of a diverse array of samples in environmental, clinical, pharmaceutical, biochemical, forensic, food science, and petrochemical laboratories. Examples of these applications are discussed in the following sections.
**Environmental Analysis** One of the most important... | {
"Header 1": "**12D.7 Quantitative Applications**",
"token_count": 1999,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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propane 2.23 min isobutane 5.71 min butane 6.67 min
What is the Kovat's retention index for each of these hydrocarbons?
#### SOLUTION
Kovat's retention index for a normal alkane is 100 times the number of carbons; thus
$$I_{\text{propane}} = 100 \times 3 = 300$$
$$I_{\text{butane}} = 100 \times 4 = 400$$
... | {
"Header 1": "**12D.7 Quantitative Applications**",
"token_count": 346,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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*Description of Method.* Trihalomethanes, such as chloroform (CHCl3) and bromoform (CHBr3), are found in most chlorinated waters. Since chloroform is a suspected carcinogen, the determination of trihalomethanes in public drinking water supplies is of considerable importance. In this method the trihalomethanes CHCl3, CH... | {
"Header 1": "**Method 12.1 Determination of Trihalomethanes in Drinking Water9**",
"token_count": 1007,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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**Scale of Operation** Analytes present at levels from major to ultratrace components have been successfully determined by gas chromatography. Depending on the choice of detector, samples with major and minor analytes may need to be diluted before analysis. The thermal conductivity and flame ionization detectors can ha... | {
"Header 1": "**12D.10 Evaluation**",
"token_count": 710,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Although gas chromatography is widely used, it is limited to samples that are thermally stable and easily volatilized. Nonvolatile samples, such as peptides and carbohydrates, can be analyzed by GC, but only after they have been made more volatile by a suitable chemical derivatization. For this reason, the various tech... | {
"Header 1": "**12E High-Performance Liquid Chromatography**",
"token_count": 267,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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An HPLC typically includes two columns: an analytical column responsible for the separation and a guard column. The guard column is placed before the analytical column, protecting it from contamination.
**Analytical Columns** The most commonly used columns for HPLC are constructed from stainless steel with internal d... | {
"Header 1": "**12E.1 HPLC Columns**",
"token_count": 577,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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A quantitative measure of a solvent's polarity.
over time. To prevent this loss of stationary phase, it is covalently bound to the silica particles. **Bonded stationary phases** are attached by reacting the silica particles with an organochlorosilane of the general form Si(CH3)2RCl, where R is an alkyl or substituted... | {
"Header 1": "**polarity index**",
"token_count": 475,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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The elution order of solutes in HPLC is governed by polarity. In a normal-phase separation the least polar solute spends proportionally less time in the polar stationary phase and is the first solute to elute from the column. Retention times are controlled by selecting the mobile phase, with a less polar mobile phase l... | {
"Header 1": "**12E.3 Mobile Phases**",
"token_count": 703,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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A reverse-phase HPLC separation is carried out using a mobile-phase mixture of 60% v/v water and 40% v/v methanol. What is the mobile phase's polarity index?
#### *SOLUTION*
From Table 12.3 we find that the polarity index is 10.2 for water and 5.1 for methanol. Using equation 12.30, the polarity index for a 60:40 w... | {
"Header 1": "**EXAMPLE 12.7**",
"token_count": 1333,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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An important feature of HPLC instrumentation (see Figure 12.26) is the presence of several solvent reservoirs. As discussed in the previous section, controlling the mobile phase's polarity plays an important role in improving a liquid chromatographic separation. The availability of several solvent reservoirs allows the... | {
"Header 1": "**12E.4 HPLC Plumbing**",
"token_count": 490,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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As with gas chromatography, numerous detectors have been developed for use in monitoring HPLC separations.14 To date, the majority of HPLC detectors are not unique to the method, but are either stand-alone instruments or modified versions of the same.
**Colorplate 12 shows a photo of an HPLC equipped with a diode arr... | {
"Header 1": "**12E.6 Detectors for HPLC**",
"token_count": 843,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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HPLC is routinely used for both qualitative and quantitative analyses of environmental, pharmaceutical, industrial, forensic, clinical, and consumer product samples. Figure 12.30 shows several representative examples.
**Preparing Samples for Analysis** Samples in liquid form can be analyzed directly, after a suitable... | {
"Header 1": "**12E.7 Quantitative Applications**",
"token_count": 350,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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The concentration of PAHs in soil can be determined by first extracting the PAHs with methylene chloride. The extract is then diluted, if necessary, and the PAHs are separated by HPLC using a UV/Vis or fluorescence detector. Calibration is achieved using one or more external standards. In a typical analysis, a 2.013-g ... | {
"Header 1": "**EXAMPLE 12.8**",
"token_count": 638,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Structures of (a) fluoxetine and (b) norfluoxetine.
—Continued
*Procedure.* A known amount of the antidepressant protriptyline is added to a serum sample, serving as an internal standard. A 0.5-mL aliquot of the serum is passed through a solid-phase extraction cartridge containing silica particles with a bonded C18... | {
"Header 1": "Figure 12.31",
"token_count": 667,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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In **liquid–solid adsorption chromatography** (LSC) the column packing also serves as the stationary phase. In Tswett's original work the stationary phase was finely divided CaCO3, but modern columns employ porous 3–10-µm particles of silica or alumina. Since the stationary phase is polar, the mobile phase is usually a... | {
"Header 1": "**12F Liquid–Solid Adsorption Chromatography**",
"token_count": 260,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
In **ion-exchange chromatography** (IEC) the stationary phase is a cross-linked polymer resin, usually divinylbenzene cross-linked polystyrene, with covalently attached ionic functional groups (Figure 12.33). The counterions to these fixed charges are mobile and can be displaced by ions that compete more favorably for ... | {
"Header 1": "**12G Ion-Exchange Chromatography**",
"token_count": 2017,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
**Single-column ion chromatography,** in which an ion-suppressor column is not needed, is possible if the concentration of ions in the mobile phase can be minimized. Typically this is done by using a stationary phase resin with a low capacity for ion exchange and a mobile phase with a small concentration of ions. Becau... | {
"Header 1": "**12G Ion-Exchange Chromatography**",
"token_count": 296,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Two classes of micron-sized stationary phases have been encountered in this section: silica particles and cross-linked polymer resin beads. Both materials are porous, with pore sizes ranging from approximately 50 to 4000 Å for silica particles and from 50 to 1,000,000 Å for divinylbenzene cross-linked polystyrene resin... | {
"Header 1": "**12H Size-Exclusion Chromatography**",
"token_count": 1254,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Despite their importance, gas chromatography and liquid chromatography cannot be used to separate and analyze all types of samples. Gas chromatography, particularly when using capillary columns, provides for rapid separations with excellent resolution. Its application, however, is limited to volatile analytes or those ... | {
"Header 1": "**12I Supercritical Fluid Chromatography**",
"token_count": 808,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Thus far all the separations we have considered involve a mobile phase and a stationary phase. Separation of a complex mixture of analytes occurs because each analyte has a different ability to partition between the two phases. An analyte whose distribution ratio favors the stationary phase is retained on the column fo... | {
"Header 1": "**12J Electrophoresis**",
"token_count": 1968,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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$$v_{\text{eof}} = \mu_{\text{eof}} E$$
12.37
Electroosmotic mobility is defined as
$$\mu_{\rm eof} = \frac{\epsilon \zeta}{4\pi \eta}$$
12.38
where $\epsilon$ is the buffer solution's dielectric constant, $\zeta$ is the zeta potential, and $\eta$ is the buffer solution's viscosity.
Examining equations ... | {
"Header 1": "**12J Electrophoresis**",
"token_count": 2012,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Joule heating is a problem because it changes the buffer solution's viscosity, with the solution at the center of the
Figure 12.41
Schematic diagram for capillary electrophoresis. The sample and source reservoir are switched when making injections.
*... | {
"Header 1": "**12J Electrophoresis**",
"token_count": 2036,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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There are several different forms of capillary electrophoresis, each of which has its particular advantages. Several of these methods are briefly described in this section.
**Capillary Zone Electrophoresis** The simplest form of capillary electrophoresis is **capillary zone electrophoresis** (CZE). In CZE the capilla... | {
"Header 1": "**12J.3 Capillary Electrophoresis Methods**",
"token_count": 2031,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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*Description of Method.* The water-soluble vitamins B1 (thiamine hydrochloride), B2 (riboflavin), B3 (niacinamide), and B6 (pyridoxine hydrochloride) may be determined by CZE using a pH 9 sodium tetraborate/sodium dihydrogen phosphate buffer or by MEKC using the same buffer with the addition of sodium dodecylsulfate. D... | {
"Header 1": "**Method 12.3 Determination of a Vitamin B Complex by CZE or MEKC18**",
"token_count": 1320,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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When compared with GC and HPLC, capillary electrophoresis provides similar levels of accuracy, precision, and sensitivity and a comparable degree of selectivity. The amount of material injected into a capillary electrophoretic column is significantly smaller than that for GC and HPLC; typically 1 nL versus 0.1 µL for c... | {
"Header 1": "**12J.5 Evaluation**",
"token_count": 279,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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adjusted retention time (*p. 551*) band broadening (*p. 553*) baseline width (*p. 548*) bleed (*p. 566*) bonded stationary phase (*p. 580*) capacity factor (*p. 551*) capillary column (*p. 562*) capillary electrochromatography (*p. 607*) capillary electrophoresis (*p. 597*) capillary gel electrophoresis (*p. 606*) capi... | {
"Header 1": "**12K KEY TERMS**",
"token_count": 914,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Chromatography and electrophoresis are powerful analytical techniques that can separate a sample into its components while providing a means for determining their concentration. Chromatographic separations utilize the selective partitioning of the sample's components between a stationary phase that is immobilized withi... | {
"Header 1": "**12L SUMMARY**",
"token_count": 738,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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*The following experiments may be used to illustrate the application of chromatography and electrophoresis to a number of different types of samples. Experiments are grouped by the type of technique, and each is briefly annotated.*
The first set of experiments describes the applicatio... | {
"Header 1": "**12M** *Suggested* **EXPERIMENTS**",
"token_count": 2047,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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Educ.* **1997,** *74*, 1130–1132.
Caffeine in coffee, tea, and soda is determined by a solid-phase microextraction using an uncoated silica fiber, followed by a GC analysis using a capillary SPB-5 column with an MS detector. Standard solutions are spiked with $^{13}$ C<sub>3</sub> caffeine as an internal standard. ... | {
"Header 1": "**12M** *Suggested* **EXPERIMENTS**",
"token_count": 2046,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
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The third set of experiments provides a few representative applications of ion chromatography.
Bello, M. A.; Gustavo González, A. "Determination of Phosphate in Cola Beverages Using Nonsuppressed Ion Chromatography," *J. Chem. Educ.* **1996**, *73*, 1174–1176.
In this experiment phosphate is determined by single-... | {
"Header 1": "**12M** *Suggested* **EXPERIMENTS**",
"token_count": 1905,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
**1.** The following data were obtained for four compounds separated on a 20-m capillary column.
| Compound | t <sub>r</sub><br>(min) | w<br>(min) |
|----------|-------------------------|------------|
| Α | 8.04 | 0.15 |
| В | 8.26 | 0.15 |
| C | ... | {
"Header 1": "3 12",
"Header 3": "12N PROBLEMS",
"token_count": 1923,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
units) |
|-----------|-----------------------------|
| 0.00 | 1.15 |
| 0.0145 | 2.74 |
| 0.0472 | 6.33 |
| 0.0951 | 11.58 |
| 0.1757 | 20.43 |
| 0.2901 | 32.97 |
(... | {
"Header 1": "3 12",
"Header 3": "12N PROBLEMS",
"token_count": 1881,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
**21.** Haddad and associates report the following capacity factors for the reverse-phase separation of salicylamide (*k* ′ sal) and caffeine (*K* ′ caff).27
| %v/v methanol | 30% | 35% | 40% | 45% | 50% | 55% |
|---------------|-----|-----|-----|-----|-----|-----|
| k ′sal | 2.4 | 1.6 | 1.6 | 1.0 | 0.7 | 0.... | {
"Header 1": "3 12",
"Header 3": "12N PROBLEMS",
"token_count": 2033,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
(a) Adding EDTA to the mobile phase eliminates the interference caused by Ca2+ and Mg2+; explain why. (b) A standard solution containing 1.0 M NaHCO3, 0.20 mM NaNO2, 0.20 mM MgSO4, 0.10 mM CaCl2, and 0.10 mM Ca(NO3)2 gives the following typical peak areas (arbitrary units).
| Ion | –<br>HCO3 | Cl– | –<br>NO2 ... | {
"Header 1": "3 12",
"Header 3": "12N PROBLEMS",
"token_count": 2050,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
| Alkylpyridine | (cm2 V–1 s–1)<br>lep |
|-----------------|----------------------|
| 2-ethylpyridine | 3.222 × 10–4 |
| 3-ethylpyridine | 3.366 × 10–4 |
| 4-ethylpyridine | 3.397 × 10–4 |
(f) The p*K*<sup>a</sup> for pyridine is 5.229. At a pH of 2.5 the electrophoretic mobility of pyridi... | {
"Header 1": "3 12",
"Header 3": "12N PROBLEMS",
"token_count": 201,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The following texts provide a good introduction to the broad field of separations, including chromatography and electrophoresis.
Giddings, J. C. *Unified Separation Science.* Wiley-Interscience: New York, 1991.
Karger, B. L.; Snyder, L. R.; Harvath, C. *An Introduction to Separation Science.* Wiley-Interscience: Ne... | {
"Header 1": "**12O SUGGESTED READINGS**",
"token_count": 1191,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
- 1. Craig, L. C. *J. Biol. Chem.* **1944,** *155,* 519.
- 2. Martin, A. J. P.; Synge, R. L. M. *Biochem. J.* **1941,** *35,* 1358.
- 3. Giddings, J. C. *Unified Separation Science.* Wiley-Interscience: New York, 1991.
- 4. Hawkes, S. J. *J. Chem. Educ.* **1983,** *60,* 393–398.
- 5. Kennedy, R. T.; Jorgenson, J. W. *A... | {
"Header 1": "**12P REFERENCES**",
"token_count": 1414,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
**A**system under thermodynamic control is in a state of equilibrium, and its signal has a constant, or steady-state value (Figure 13.1a). When a system is under kinetic control, however, its signal changes with time (Figure 13.1b) until equilibrium is established. Thus far, the techniques we have considered have invol... | {
"Header 1": "Kinetic Methods of Analysis",
"token_count": 435,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The earliest examples of analytical methods based on chemical kinetics, which date from the late nineteenth century, took advantage of the catalytic activity of enzymes. Typically, the enzyme was added to a solution containing a suitable substrate, and the reaction between the two was monitored for a fixed time. The en... | {
"Header 1": "**13A Methods Based on Chemical Kinetics**",
"token_count": 1996,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The initial concentration of analyte, $[A]_0$ , is calculated using equation 13.2, 13.6, or 13.8, depending on whether the reaction follows first-order, pseudo-first-order, or pseudo-zero-order kinetics. The rate constant for the reaction is determined in a separate experiment using a standard solution of analyte. Alt... | {
"Header 1": "**13A Methods Based on Chemical Kinetics**",
"token_count": 2022,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
In the one-point variable-time integral method, the time needed to cause a desired change in concentration is measured from the start of the reaction. With the two-point variable-time integral method, the time required to effect a change in concentration is measured.
One important application of the variable-time int... | {
"Header 1": "**13A Methods Based on Chemical Kinetics**",
"token_count": 1017,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The concentration of aluminum in serum can be determined by adding 2-hydroxy-1-naphthaldehyde *p*-methoxybenzoyl-hydrazone and measuring the initial rate of the resulting complexation reaction under pseudo-first-order conditions.10 The rate of reaction is monitored by the fluorescence of the metal–ligand complex. Initi... | {
"Header 1": "**EXAMPLE 13.4**",
"token_count": 643,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The data shown in the following table were collected for a reaction known to follow pseudo-zero-order kinetics during the time in which the reaction was monitored.
| Time<br>(s) | [A]t<br>(mM) |
|-------------|--------------|
| 3 | 0.0731 |
| 4 | 0.0728 |
| 5 | 0.0681 |... | {
"Header 1": "**EXAMPLE 13.5**",
"token_count": 540,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
*Description of Method.* Creatine is an organic acid found in muscle tissue that supplies energy for muscle contractions. One of its metabolic products is creatinine, which is excreted in urine. Because the concentration of creatinine in urine and serum is an important indication of renal function, rapid methods for it... | {
"Header 1": "**Method 13.1 Determination of Creatinine in Urine11**",
"token_count": 1119,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Quantitative information about a chemical reaction can be made using any of the techniques described in the preceding chapters. For reactions that are kinetically slow, an analysis may be performed without worrying about the possibility that significant changes in concentration occur while measuring the signal. When th... | {
"Header 1": "**13A.2 Instrumentation**",
"token_count": 1997,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Chemical kinetic methods have been applied to the quantitative analysis of a number of enzymes and substrates.<sup>13</sup> One example, is the determination of glucose based on its oxidation by the enzyme glucose oxidase.<sup>6</sup>
Glucose +
$$H_2O + O_2$$
glucose oxidase $\rightarrow$ gluconolactone + $H_2O_... | {
"Header 1": "**13A.2 Instrumentation**",
"token_count": 1725,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
**Scale of Operation** The detection limit for chemical kinetic methods ranges from minor components to ultratrace components (see Figure 3.6 in Chapter 3) and is principally determined by two factors: the rate of the reaction and the instrumental method used for monitoring the rate. Because the signal is directly prop... | {
"Header 1": "**13A.5 Evaluation of Chemical Kinetic Methods**",
"token_count": 2011,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Again, a pair of simultaneous equations at times $t_1$ and $t_2$ can be solved for $[A]_0$ and $[B]_0$ .
Equation 13.23 can also be used as the basis for a curve-fitting method. As shown in Figure 13.14, a plot of $ln(C_t)$ as a function of time consists of two regions. At short times the plot is curved si... | {
"Header 1": "**13A.5 Evaluation of Chemical Kinetic Methods**",
"token_count": 329,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Atoms with the same number of protons but a different number of neutrons are called **isotopes.** To identify an isotope we use the symbol ${}^{A}_{Z}E$ , where E is the element's atomic symbol, Z is the element's atomic number (which is the number of protons), and A is the element's atomic mass number (which is the s... | {
"Header 1": "13B Radiochemical Methods of Analysis",
"token_count": 1565,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
#### EXAMPLE 13.6
The activity in a 10.00-mL sample of radioactive wastewater containing $^{90}_{38}$ Sr was found to be $9.07 \times 10^6$ disintegrations/s. What is the molar concentration of $^{90}_{38}$ Sr in the sample? The half-life for $^{90}_{38}$ Sr is 28.1 years.
Substituting equation 13.27 into equa... | {
"Header 1": "9",
"token_count": 2029,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The sample is then processed to isolate $w_{\rm A}$ grams of purified analyte, containing both radioactive and nonradioactive materials. The activity of the isolated sample, $A_{\rm A}$ , is measured. If all the analyte, both radioactive and nonradioactive, is recovered, then $A_{\rm A}$ and $A_{\rm T}$ will be ... | {
"Header 1": "9",
"token_count": 2038,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The focus of this chapter is on methods in which the signal is time-dependent. Methods based on the kinetics of chemical and nuclear reactions were presented in the previous two sections. In this section we consider the technique of flow injection analysis. In this technique the sample is injected into a flowing carrie... | {
"Header 1": "13C Flow Injection Analysis",
"token_count": 1833,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The basic components of a flow injection analyzer are shown in Figure 13.16 and include a unit for propelling the carrier stream, a means for injecting the sample into the carrier stream, and a detector for monitoring the composition of the carrier stream. These units are connected by a transport system that provides a... | {
"Header 1": "**13C.2 Instrumentation**",
"token_count": 2001,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
W B I
P
(with sample)
R1
S
C
C
W
D
C
**Figure 13.24**
Separation module for a flow injection analysis using a semipermeable membrane for dialysis and gaseous diffusion.
Aqueous phase Waste
Acceptor stream Detector
#### **Figure... | {
"Header 1": "**13C.2 Instrumentation**",
"token_count": 835,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
In a quantitative flow injection analysis a calibration curve is determined by injecting standard samples containing known concentrations of analyte. The format of the calibration curve, such as absorbance versus concentration, is determined by the method of detection. Calibration curves for standard spectroscopic and ... | {
"Header 1": "**13C.3 Quantitative Applications**",
"token_count": 1032,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
*Description of Method.* The FIA determination of phosphate is an adaptation of a standard spectrophotometric analysis for phosphate. In the presence of acid, phosphate reacts with molybdate to form a yellow-colored complex in which molybdenum is present as Mo(VI).
$$H_3PO_4(aq) + 12H_2MoO_4(aq) \rightleftharpoons H_... | {
"Header 1": "**Method 13.2 Determination of Phosphate by FIA27**",
"token_count": 998,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The majority of FIA applications are modifications of conventional titrimetric, spectrophotometric, and electrochemical methods of analysis. For this reason it is appropriate to evaluate FIA in relation to these conventional methods. The scale of operations for FIA allows for the routine analysis of minor and trace ana... | {
"Header 1": "**13C.4 Evaluation**",
"token_count": 543,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
alpha particle (*p. 642*) beta particle (*p. 642*) enzyme (*p. 636*) fiagram (*p. 650*) flow injection analysis (*p. 649*) gamma ray (*p. 642*) Geiger counter (*p. 643*) half-life (*p. 643*) isotope dilution (*p. 646*)
isotopes (*p. 642*) Lineweaver–Burk plot (*p. 638*) manifold (*p. 652*) Michaelis constant (*p. 637... | {
"Header 1": "**13D KEY TERMS**",
"token_count": 274,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Kinetic methods of analysis are based on the rate at which a chemical or physical process involving the analyte occurs. Three types of kinetic methods are discussed in this chapter: chemical kinetic methods, radiochemical methods, and flow injection analysis.
Chemical kinetic methods are based on the rate at which a ... | {
"Header 1": "**13E SUMMARY**",
"token_count": 517,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
*The following experiments may be used to illustrate the application of kinetic methods of analysis. Experiments are divided into two groups: those based on chemical kinetics and those using flow injection analysis. Each suggested experiment includes a brief description.*
The followin... | {
"Header 1": "**13F** *Suggested* **EXPERIMENTS**",
"token_count": 1603,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
**1** Equation 13.14 shows how [A]0 is determined for a two-point fixed-time integral method in which the concentration of A for the pseudo-first-order reaction
$$A + R \rightarrow P$$
is measured at times *t*<sup>1</sup> and *t*2. Derive a similar equation for the case when the product is monitored under pseudo-fi... | {
"Header 1": "**13G PROBLEMS**",
"token_count": 1905,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
| [urea]<br>(M) | Rate<br>(Ms <sup>-1</sup> ) |
|-----------------------|-----------------------------|
| $1.00 \times 10^{-7}$ | $6.25 \times 10^{-6}$ |
| $2.00\times10^{-7}$ | $1.25\times10^{-5}$ |
| $3.00 \times 10^{-7}$ | $1.88\times10^{-5}$ |
| $4.00\times10^{-7}$ | $2.50\times1... | {
"Header 1": "**13G PROBLEMS**",
"token_count": 2029,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
| Cl–<br>(ppm) | Absorbance |
|--------------|------------|
| 5.00 | 0.057 |
| 10.00 | 0.099 |
| 20.00 | 0.230 |
| 30.00 | 0.354 |
| 40.00 | 0.478 |
| 50.00 | 0.594 |
| 75.00 | 0.840 |
| | |
A 1.00-mL sample... | {
"Header 1": "**13G PROBLEMS**",
"token_count": 1655,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
The following source provides a general review of the importance of kinetics in analytical chemistry.
Mottola, H. A. "Some Kinetic Aspects Relevant to Contemporary Analytical Chemistry." *J. Chem. Ed.* **1981,** *58,* 399–403.
A brief history of chemical kinetic methods of analysis is found in the following text. ... | {
"Header 1": "**13H SUGGESTED READINGS**",
"token_count": 1069,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
- 1. Method 4500-NO2 – B in *Standard Methods for the Analysis of Waters and Wastewaters,* 20th ed. American Public Health Association: Washington, D.C., 1998, pp. 4-112–4-114.
- 2. Karayannis, M. I.; Piperaki, E. A.; Maniadake, M. M. *Anal. Lett.* **1986,** *19,* 13–23.
- 3. Pardue, H. L. *Anal. Chim. Acta* **1989,** ... | {
"Header 1": "**13I REFERENCES**",
"token_count": 1622,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
In the presence of H2O2 and H2SO4, solutions of vanadium form a reddish brown color that is believed to be a compound with the general formula (VO)2(SO4)3. Since the intensity of the color depends on the concentration of vanadium, the absorbance of the solution at a wavelength of 450 nm can be used for the quantitative... | {
"Header 1": "**14A Optimizing the Experimental Procedure**",
"token_count": 287,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
One of the most effective ways to think about optimization is to visualize how a system's response changes when we increase or decrease the levels of one or more of its factors. A plot of the system's response as a function of the factor levels is called a **response surface.** The simplest response surface is for a sy... | {
"Header 1": "**14A.1 Response Surfaces**",
"token_count": 821,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Imagine that you wish to climb to the top of a mountain. Because the mountain is covered with trees that obscure its shape, the shortest path to the summit is unknown. Nevertheless, you can reach the summit by always walking in a direction that moves you to a higher elevation. The route followed (Figure 14.3) is the re... | {
"Header 1": "**14A.2 Searching Algorithms for Response Surfaces**",
"token_count": 2034,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
Equation 14.2, for example, contains a final term accounting for the interaction between the factors A and B.
$$R = 5.5 + 1.5A + 0.6B - 0.15A^2 - 0.0245B^2 - 0.0857AB$$
14.2
The resulting response surface for equation 14.2 is shown in Figure 14.7a.
**Figure 14.6**Factor effect plot... | {
"Header 1": "**14A.2 Searching Algorithms for Response Surfaces**",
"token_count": 1967,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
| Table 14.3 | Progress of Fixed-Sized Simplex |
|------------|---------------------------------|
| | Optimization for Response |
| | Surface in Figure 14.10 |
| Simplex | Vertices | Notes | |
|---------|------------|-----------------------------|--|
| 1 ... | {
"Header 1": "**14A.2 Searching Algorithms for Response Surfaces**",
"token_count": 901,
"source_pdf": "datasets/websources/biochem/Modern analytical chemistry by David Harvey.pdf"
} |
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