Standard solution

Abstract: Preface. Preface to the First Edition. List of Acronyms and Symbols. 1. General introduction. 1.1 Principles of headspace analysis . 1.2 Types of headspace analysis. 1.2.1 Principles of static headspace - gas chromatography (HS-GC). 1.2.2 Principles of dynamic headspace -- gas chromatography. 1.3 The evolution of the HS-GC methods. 1.4 Headspace -- gas chromatography literature. 1.5 Regulatory methods utilizing (static) HS-GC. 1.6 References. 2. Theoretical background of HS-GC and its applications. 2.1 Basic theory of headspace analysis. 2.2 Basic physicochemical relationships. 2.3 Headspace sensitivity. 2.3.1 Influence of temperature on vapor pressure and partition coefficient. 2.3.2 Influence of temperature on headspace sensitivity for compounds with differing partition coefficients. 2.3.3 Influence of sample volume on headspace sensitivity for compounds with differing partition coefficients. 2.3.4 Changing the sample matrix by varying the activity coefficient. 2.4 Headspace linearity. 2.5 Duplicate analyses. 2.6 Multiple headspace extraction (MHE). 2.6.1 Principles of MHE. 2.6.2 Theoretical background of MHE. 2.6.3 Simplified MHE calculation. 2.7 References. 3. The technique of HS-GC. 3.1 Sample vials. 3.1.1 Types. 3.1.2 Selection of vial volume. 3.1.3 Vial cleaning. 3.1.4 Wall adsorption effects. 3.2 Caps. 3.2.1 Pressure on caps. 3.2.2 Safety closures. 3.3 Septa. 3.3.1 Types. 3.3.2 Septum blank. 3.3.3 Should a septum be pierced twice?. 3.4 Thermostatting. 3.4.1 Influence of temperature. 3.4.2 Working modes. 3.5 The fundamentals of headspace sampling systems. 3.5.1 Systems using gas syringes. 3.5.2 Solid-phase microextraction (SPME). 3.5.2.1 Comparison of the sensitivities in HS-SPME and direct static HS-GC. 3.5.3 Balanced-pressure sampling systems. 3.5.4 Pressure/loop systems. 3.5.5 Conditions for pressurization systems. 3.5.6 The volume of the headspace sample. 3.5.6.1 Sample volume with gas syringes. 3.5.6.2 Sample volume with loop systems. 3.5.6.3 Sample volume with the balanced-pressure system. 3.6 Use of open-tubular (capillary) columns. 3.6.1 Properties of open-tubular columns for gas samples. 3.6.2 Headspace sampling with split or spitless?. 3.6.3 Comparison of split- and splitless headspace sampling. 3.6.4 Band broadening during sample introduction. 3.6.5 Temperature influence on band broadening. 3.6.6 The combination of different columns and detectors. 3.7 Enrichment techniques in HS-GC. 3.7.1 Systems for cryogenic trapping. 3.7.1.1 Systems for Cryogenic condensation. 3.7.1.2 Trapping by cryogenic focusing. 3.7.1.3 Influence of temperature on cryogenic focusing. 3.7.1.4 Comparison of the various techniques of cryogenic trapping. 3.7.2 Influence of water in cryogenic HS-GC. 3.7.2.1 Water removal in static HS-GC. 3.7.2.2 Applications. 3.7.3 Enrichment by adsorption. 3.7.3.1 Water removal from an adsorption trap. 3.8 Special techniques with the balanced-pressure systems. 3.8.1 Instrumentation for MHE. 3.8.2 Backflushing. 3.9. Reaction HS-GC. 3.9.1 Derivatization in the headspace vial. 3.9.1.1 Methylation. 3.9.1.2 Esterification. 3.9.1.3 Transesterification. 3.9.1.4 Acetylation. 3.9.1.5 Carbonyl compounds. 3.9.2 Subtraction HS-GC. 3.9.3 Special reactions. 3.9.4 HS-GC analysis of volatile derivatives from inorganic compounds. 3.10 References. 4. Sample handling in HS-GC. 4.1 Equilibration. 4.1.1 Gas samples. 4.1.2 Liquid samples. 4.1.3 Solid samples. 4.2 Solution approach. 4.3 Sample handling and sample introduction. 4.3.1 Gas samples. 4.3.2 Liquid samples. 4.3.3 Solid samples. 4.4 Preparation of standard solutions. 4.4.1 Preparation of a standard solution from a liquid or solid substance. 4.4.2 Preparation of a standard solution from a gaseous compound. 4.5 Influence of the matrix. 4.5.1 Clean matrix is available. 4.5.2 Matric effect can be eliminated. 4.5.3 Artificial matrix can be prepared. 4.6 Methods aiming the complete evaporation of the analyte. 4.6.1 The total vaporization technique (TVT). 4.6.2 The full evaporation technique (FET). 4.6.3 Calculation of the extraction yield in FET. 4.6.4 Comparison of headspace sensitivities. 4.7 References. 5. Headspace methods for quantitative analysis. 5.1 Internal normalization. 5.2 Internal standard method. 5.3 External standard method. 5.4 Standard addition method. 5.4.1 Single addition. 5.4.2 Handling of the added standard (Gas-phase addition and sample-phase addition). 5.4.3 Determination by multiple additions. 5.5 Multiple headspace extraction (MHE). 5.5.1 Principles of MHE. 5.5.2 Calibration in MHE. 5.5.2.1 External standard. 5.5.2.2 Internal standard. 5.5.2.3 Standard addition. 5.5.3 The use of gaseous external standards in MHE. 5.5.4 The role of quotient Q. 5.5.4.1 Relationship between Q and pressures. 5.5.4.2 Value of Q in the case of total vaporization. 5.5.4.3 The relative position of the MHE plots as a function of Q. 5.5.5 The correlation coefficient (r). 5.5.6 Evaluation of the shape of the regression plot. 5.5.7 Influence of K/s. 5.6 Analysis of solid samples (adsorption systems). 5.6.1 Suspension approach. 5.6.2 Surface-modification techniques. 5.6.3 Highly adsorptive samples. 5.7 Calibration techniques with headspace samples of varying volumes. 5.8 Analysis of gas samples. 5.9 References. 6. Method development in HS-GC. 6.1 General guidelines. 6.2 Determination of the residual monomer content of polystyrene pellets. 6.2.1 First approach: use of internal standard with MHE. 6.2.2 Second approach: single determination with internal standard. 6.2.3 Third approach: use of external standard with MHE. 6.2.4 Fourth approach: use of the solution approach. 6.3 Determination of residual solvents in a printed plastic film. 6.3.1 First approach: use of external standard with MHE. 6.3.2 Second approach: use of standard addition with MHE. 6.3.3 Third approach: use of internal standard. 6.4 Determination of the volatile constituents of a cathodic electrolytic plating bath. 6.4.1 First approach: use of external standard with MHE. 6.4.2 Second approach: dilution and use of external standard. 7. Nonequilibrium static headspace analysis. 7.1 Accelerated analysis. 7.2 Heat-sensitive samples. 7.3 References. 8. Qualitative analysis by HS-GC. 8.1 The use of HS-GC in 'fingerprinting.'. 8.2 The use of headspace sampling in hyphenated systems. 8.3 The use of HS-GC in microbiology. 8.4 References. 9. Special measurements. 9.1 Determination of vapor pressures. 9.2 Determination of activity coefficients. 9.3 Determination of related physicochemical functions. 9.4 Determination of phase distribution (partition coefficient). 9.4.1 The vapor-phase calibration (VPC) method. 9.4.2 The phase-ratio variation (PRV) method. 9.4.3 MHE methods for the determination of the partition coefficient. 9.5 Reaction constant measurements. 9.6 Determination of solute solubility by MHE. 9.7 Gas-solid systems. 9.7.1 Determination of adsorption isotherms. 9.7.2 Determination of the rate of release of a volatile analyte. 9.8 Validation of the headspace instrumentation: investigation of detector linearity and detection limit. 9.8.1 Definitions. 9.8.2 Linear range of the detector. 9.8.3 Precision of the range. 9.8.4 Minimum detectability. 9.9 References. Index.

Abstract: Preface and Acknowledgments.- Notes on Calculation of Concentration.- Nutritional Labeling Using a Computer Program.- Assessment of Accuracy and Precision.- Determination of Moisture Content.- Determination of Fat Content.- Protein Nitrogen Determination.- Phenol-Sulfuric Acid Method for Total Carbohydrate.- Vitamin C Determination by Indophenol Method.- Complexometric Determination of Calcium.- Iron Determination in Meat Using Ferrozine Assay.- Sodium Determination Using Ion Selective Electrodes, Mohr Titration, and Test Strips.- Sodium and Potassium Determinations by Atomic Absorption Spectroscopy and Inductively Coupled Plasma-Atomic Emission Spectroscopy.- Standard Solutions and Titratable Acidity.- Fat Characterization.- Fish Muscle Proteins: Extraction, Quantitation, and Electrophoresis.- Enzyme Analysis to Determine Glucose Content.- Gliadin Detection in Food by Immunoassay.- Examination of Foods for Extraneous Materials.- High Performance Liquid Chromatography.- Gas Chromatography.- Viscosity Measurement Using a Brookfield Viscometer.- Calculation of CIE Color Specifications from Reflectance or Transmittance Spectra.

Abstract: Microscopic fluid inclusions in minerals are the main source of information about the chemical composition of fluids associated with large-scale material transport in the Earth's interior. Hydrothermal transport processes are responsible for the natural enrichment of metal resources in many ore deposits. For the multi-element analysis of the microscopic fluid inclusions (typically 5–50 µm in diameter), LA-ICP-MS has become one of the most promising techniques owing to the recent progress in laser optics design and the development of high-sensitivity ICP mass spectrometers. The quantitative analyses of 19 major, minor and trace elements covering a concentration range of five orders of magnitude were carried out on 39 single natural fluid inclusions, together with a number of experiments to optimise controlled ablation and to test the calibration procedure. A modified commercial ICP-MS instrument was used together with a prototype ablation system based on a 193 nm excimer laser. In a stepwise opening procedure for complex polyphase inclusions, a small hole (4 µm pit) was first drilled for the partial release of liquid and vapor, followed by complete drilling out using a pit covering the entire inclusion. Controlled ablation improves the reproducibility of element ratios to less than 20% for most major, minor and trace elements measured in an assemblage of cogenetic inclusions (including elements that are initially present as solid precipitates within the inclusion), provided that the entire transient ICP-MS signal is integrated. Element ratios were calculated from integrated intensity ratios using an external standard, either a NIST SRM glass or an aqueous standard solution ablated directly through a plastic film. Absolute concentrations were calculated from the element ratiosviaan internal standard element, whose concentration was determined prior to ablation. Microthermometric measurements of phase transitions were used to determine total salinity from known phase diagrams, by measuring either the depression of ice-melting temperature, or the temperature of dissolution of NaCl crystals. Salinity can be related to the concentration of Na (or in some cases Cl), which serves as the internal standard element for the quantification of trace element concentrations. Calculated limits of detection are in the ng g–1to µg g–1region, depending on the volume of the inclusions. The accuracy of the overall analysis, including internal and external calibration, is typically between 5 and 20%, as demonstrated on alkali elements in synthetic fluid inclusions of known composition.