Excess Volumes

Introduce a 0.30 pL portion of the solvent extract into the gas chromatograph. It is found that solutions of concentrations greater than 0.3 M are unsuitable as they deposit solid and thus cause a blockage of the 1 jj.L microsyringe used for the injection of the sample. The syringe is flushed several times with the sample solution, filled with the sample to the required volume, excess liquid wiped from the tip of the needle and the sample injected into the chromatograph. 

Administration of oxytocin may result in fetal bradycardia, uterine rupture, uterine hypertonicity, nausea, vomiting, cardiac arrhythmias, and anaphylactic reactions. Serious water intoxication (fluid overload, fluid volume excess) may occur, particularly when the drug is administered by continuous infusion and the patient is receiving fluids by mouth. When used as a nasal spray, adverse reactions are rare. 

When oxytocin is administered IV, there is a danger of a fluid volume excess (water intoxication) because oxytocin has an antidiuretic effect. The nurse measures the fluid intake and output. In some instances, hourly measurements of the output are necessary. The nurse observes die patient for signs of fluid overload (see Chap. 58). If any of these signs or symptoms is noted, die nurse should immediately discontinue die oxytocin infusion and run die primary IV line at die rate prescribed by die primary healtii care provider until the primary health care provider examines die patient. 

No evidence of a fluid volume excess (oxytocin administration) is seen. 

Water and excess diol were removed by distillation under high vacuum to yield a solid mass. The latter was swollen in refluxing ethyl acetate (sufficient to make the mass mobile) and the resulting mixture poured into -hexane ( 3 fold volume excess). 

Agreement is also poor concerning entropy and volume excess terms. Because divalent cations (Mg, Ca, Fe, Mn) occupy only dodecahedral sites whereas octahedral sites are reserved for trivalent cations (Cr, Fe, Al), each cation has only one site at its disposal and permutability is fixed by stoichiometry (cf. section 3.8.1). As regards the occupancy on tetrahedral positions, we have already seen that analyses of natural specimens show silicon deficiencies, compensated by AF ... 

The volume of a chromatography system outside of the column from the point of injection to the point of detection is called the dead volume, or the extra-column volume. Excessive dead volume allows bands to broaden by diffusion or mixing. Use short, narrow tubing whenever possible, and be sure that connections are made with matched fittings to minimize dead volume and thereby minimize extra-column band spreading. 

The benzylbromomalonic acid containing water is now heated in an oil bath to 125°—130°, and the fused mass evolves carbon dioxide and a certain amount of hydrobromic acid. The reaction is complete in the course of 30—45 minutes. The residue is a yellow oil, which even at a low temperature does not crystallise, and which in the main consists of phenyl-a-bromopropionic acid. For the purpose of purification it is washed with water, taken up in ether, and dried with anhydrous sodium sulphate the ether is then distilled off. The mobile, almost colourless oil remaining is dissolved in 5 times its volume (excess) of 25% aqueous ammonia, and either heated for 3 hours to 100° in a sealed tube or allowed to stand for 3 to 4 days at ordinary temperature. On evaporation of the ammo-niacal solution an almost colourless residue is left, and this chiefly consists of ammonium bromide and phenylalanine. On boiling with absolute alcohol the amino-acid is left undissolved and is recrystallised from hot water. 

FIGURE 3.6 Comparison of surface excess free energy (AGs) and volume excess free energy (AGv) as functions of cluster size. (Reproduced and modified from Larson, M.A., Garside, J., Chem. Eng. Sci., 41, 1285 (1986). With permission from Elsevier.)... 

How do we take into account the contribution of dangling chains to Tg In linear polymers, we know that chain ends carry on a free volume excess and, thus, play a plasticizing effect that can expressed through a copolymer law ... 

Dialysis should be conducted at 4°C against a 50- to 100-fold volume excess of the appropriate buffer for at least 8 h with one change of buffer. If the volume of material to be dialysed makes this volume excess impracticable, then a smaller volume may be used and additional buffer changes incorporated. 

Failure to allow the column to drain during packing results in excessive convection currents (Figure 5-6). These currents will deposit heavy, coarse particles near the column walls and finer particles in the center of the column. Such an unevenly packed column does not flow uniformly and hence yields poor resolution. When the gel bed reaches the depth previously established as the bed volume, excess gel should be removed... 

Risk for fluid volume excess. Too much replacement fluid or fluid is infused too rapidly. 

Irans-Dichlorobis(l,2-ethanediamine)cobalt(III) chloride is prepared from [Co(en)2(C03)]Cl (150 g) and concentrated hydrochloric acid (400 mL), as described for the dibromo analog in Section 28-B. Oven drying (100°,2 hours) yields 143 g (92%). The material is recrystallized from a filtered, saturated aqueous solution by adding an equal volume of methanol and then diluting carefully with a 10-fold volume excess of acetone. After 1 hour at 5°, the fine grass-green needles are collected, washed with two portions each of acetone and then diethyl ether, and air dried. Recovery is nearly quantitative. fra s-Dichlorobis(l,2-ethanediamine)cobalt(lH) chloride (11.4 g, 40mmole) is... 

In situations where both sodium and water are lost from the ECF. hypernatraemia will occur only if more w aterthan sodium is lost.. An osmotic diuresis, as seen in the patient with diabetes mellilus. causes a deficit of both water and sodium ions and may result in hypernatraemia with decrea.sed ECF volume. Excessive sweating or diarrhoea, especially in children, may also give this picture. 

Urine volume on timed period collections should always be recorded, and water intake data or clinical observations of increased drinking must always be considered when interpreting changes of urine volumes. Excessive fluid loss by vomitus or diarrhea also will affect urine output. Some laboratories use additional water loads to achieve urine collection, but enforced diuresis can alter the excretion of urinary enzymes and metabolites. 

Risk for fluid volume excess. This can occur when the patient is given too much replacement fluid, fluid is infused too rapidly, or the volume is too much for the patient s physical size or condition. 

Signs and symptoms of fluid volume excess (overload) which include cough, dyspnea (difficulty breathing), jugular vein distention (JVD) (neck vein engorgement), moist rales (abnormal breath sounds). 

To recognize signs and symptoms of fluid volume excess and fluid volume deficit. 

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