Glucose in blood

Perhaps the most common type of problem encountered in the analytical lab is a quantitative analysis. Examples of typical quantitative analyses include the elemental analysis of a newly synthesized compound, measuring the concentration of glucose in blood, or determining the difference between the bulk and surface concentrations of Cr in steel. Much of the analytical work in clinical, pharmaceutical, environmental, and industrial labs involves developing new methods for determining the concentration of targeted species in complex samples. Most of the examples in this text come from the area of quantitative analysis. 

Enzyme sensors are based primarily on the immobilization of an enzyme onto an electrode, either a metallic electrode used in amperometry (e.g., detection of the enzyme-catalyzed oxidation of glucose) or an ISE employed in potentiometry (e.g., detection of the enzyme-catalyzed liberation of hydronium or ammonium ions). The first potentiometric enzyme electrode, which appeared in 1969 due to Guilbault and Montalvo [140], was a probe for urea with immobilized urease on a glass electrode. Hill and co-workers [141] described in 1986 the second-generation biosensor using ferrocene as a mediator. This device was later marketed as the glucose pen . The development of enzyme-based sensors for the detection of glucose in blood represents a major area of biosensor research. 

Calibration by means of results of another method. In life science and other fields there can exist cases in which no real calibration samples are available. That may concern substances of metabolism in living organisms like cholesterol and glucose in blood. 

Dose-dependent hyperglycemia, due to increased production of liver glucose, in blood of treated animals, reaching a maximum glucose level about 1 h post-injection, persisting for up to 3 days, and approaching control levels within 1 week (Saxena and Karel 1976)... 

For example, if the molahty of glucose in blood is 5.5 x 10 mol kg and in urine is 5.5 X 10 mol kg, then to transport glucose back into the blood, the kidney must perform work against this gradient equal to at least... 

Answen D. HbAlc is glycosykted HbA and is produced slowly whenever the glucose in blood is elevated. It persists until the RfiC is destroyed and the Hb degraded and so is useful as a long-term indicator of glucose level... 

Cortical hormones include glucocorticoids (cortisol/corticosterone) and mineralocorticoids (aldosterone) medullar hormones are adrenaline and noradrenaline Pancreas Regulates glucose in blood via production of the hormones glucagon and insulin... 

One of the commercial successes in this area is a miniaturised device developed for insulin-dependent diabetes, which uses glucose oxidase (GO) to measure glucose in blood (see Fig. 19.7). 

A challenge is to manufacture glucose monitors in such a reproducible manner that they do not require calibration. A user expects to add a drop of blood to the test strip and get a reliable reading without first constructing a calibration curve from known concentrations of glucose in blood. Each lot of test strips is highly reproducible and calibrated at the factory. 

Figure 18 Dynamics of carbohydrate and lactate in the muscle and blood of horse-mackerel during cruise swimming. The fatigue point lies anywhere between 8 and 10 h after the start. The starting level is assumed to be 100% and the curves show the percentage increase or decrease. O, glycogen in white muscle A, glycogen in red muscle , lactate in white muscle V, lactate in red muscle O, glucose in blood , lactate in blood.

H2. Hoffman, W. S., A rapid photoelectric method for the determination of glucose in blood and urine. ]. Biol. Chem. 120, 51-55 (1937). 

During the past 40 years there have been numerous exciting extensions of electrochemistry to the field of analytical chemistry. A series of selective-ion potentiometric electrodes have been developed, such that most of the common ionic species can be quantitatively monitored in aqueous solution. A highly effective electrolytic moisture analyzer provides continuous online assays for water in gases. Another practical development has been the voltammetric membrane electrode for dioxygen (02), which responds linearly to the partial pressure of 02, either in the gas phase or in solution. The use of an immobilized enzyme (glucose oxidase) on an electrode sensor to assay glucose in blood is another extension of electrochemistry to practical analysis. 

Trinder, P. (1969). Determination of Glucose in Blood Using Glucose Oxidase with an Alternative Oxygen Acceptor. Ann Clin Biochem 6 24. 

Starch mixed with such polysaccharide gums as guar, xanthan, and locust bean are used as food thickeners, especially when a surfactant is added.1055 A composition of guar gum coated with starch has been patented for decreasing levels of cholesterol and glucose in blood.1057 Starch blended with achrodextrin, gum arabic, and sodium silicate is used as an adhesive for book binding.1058... 

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