Gas chromatographic determination of aromatic amines in water samples after solid-phase extraction and derivatization with iodine. I. Derivatization.

A new method for the selective determination of aromatic amines is presented, which is based on the solid-phase extraction at pH 9 and subsequent derivatization of the analytes to the corresponding iodobenzenes. These can selectively and sensitively be determined with gas chromatography and electron-capture detection. Separation of at least 30 compounds in a single chromatographic run in 30 min is possible. With this method, 56 aromatic amines were investigated, and only in six cases no derivatives were obtained. Limits of quantitation were between 0.5 and 8 micrograms 1(-1), but may still be lowered with higher sample volumes or different injection techniques. The application to water samples revealed the suitability for the investigation of ground, leachate and wastewater.

Gas chromatographic determination of aromatic amines in water samples after solid-phase extraction and derivatization with iodine. II. Enrichment.

A procedure for the enrichment of aromatic amines via solid-phase extraction was developed. A HR-P phase based on styrene-divinylbenzene was used for the investigations, generally followed by derivatization with iodine and determination via GC-ECD. The recoveries of 53 aromatic amines in a drinking water matrix at pH 9 were determined. Most anilines showed relative recoveries between 80-120% with relative standard deviations of< or = 5% at concentration levels between 10 and 20 micrograms 1(-1). The comparison with a wastewater matrix led to similar results. The enrichment procedure was applied to real samples, e.g., samples of ammunition wastewater.

Effects of passive physical exercise on peripheral vision in muscular dystrophic children.

To investigate the effects of passive exercise of the extremities on peripheral vision of muscular dystrophic children aged 9 to 13 yr. these subjects were either not exercised (control days) for a 6-min. period or were exercised (experimental days) for a 6-min. period after a 5-min. rest. Peripheral vision was recorded after each condition. Analysis of variance with repeated measures on the exercise and no exercise conditions was computed for each measure. 6 min. of passive exercise significantly increased peripheral vision. It was assumed that exercise increased blood flow through the lungs allowing for greater oxygen diffusion in the brain and other facilitory responses which increased effective cerebral activity. Curriculum revisions for such children indicate the importance of activity in facilitating subsequent learning.

Exercise effect on strength and range of motion of hand intrinsic muscles and joints.

The intrinsic muscles of the hand are largely neglected in training, mainly because certain biomechanical principles must be applied in order for these muscles to be involved in hand exercises. Following these principles, a system of stretching and isometric exercises was developed. Twelve men exercised for four weeks, three times daily. Significant improvement in seven out of the 12 strength measurements was noted. Exercise seemed to affect just the metacarpophalangeal joints range of motion, while distal and proximal interphalangeal joints remained largely unaffected.

Lung pH and pulmonary absorption of nonvolatile drugs in the rat.

The effect of pH on pulmonary absorption of nonvolatile drugs was investigated in the rat. Krebs-Ringer phosphate solutions (pH 6.2 and 7.4), Krebs-Ringer pyrophosphate solution (pH 8.4), or an unbuffered salt solution containing a drug were administered through tight-fitting tracheal cannulas to anesthetized animals. After 3 min, the lungs were removed and assayed for the amount of drug that remained. Weak acids and a weak base were absorbed most rapidly at pH values at which the drugs were least ionized. For example, with the base procainamide, 36% of the dose was absorbed at pH 6.2 and 76% at pH 8.4. With the acid sulfisoxazole, 71% was absorbed at pH 6.2 and 55% at pH 8.4. Similarly, with p-aminosalicylic acid, 77% was absorbed at pH 6.2 and 40% at pH 8.4. In contrast to these results, compounds such as urea and amitrole, which remain completely nonionized over the pH range studied, showed no change in absorption rate when the pH was varied. The two weak acids and the weak base were absorbed from an unbuffered solution as though the pH at the site of drug absorption was between 6.2 and 7.4. The absorption rate for each weak electrolyte from unbuffered solution, when compared graphically with the respective absorption rates from buffered solutions, indicated that the pH at the site of drug absorption is about 6.6.

Effects of manipulation of augmented knowledge of results and work surface angle on performance of a serial positioning task.

The effects of manipulating augmented information feedback on performance efficiency of 24 male adults in a simple motor skill were studied. The three levels of information feedback were no augmented knowledge of results, positive augmented knowledge of results and negative augmented knowledge of results, using light and tone as signal modes. The motor skill was a serial-positioning movement, simulating many industrial assembly tasks, and was given at three work surface angles (0 degrees, 9 degrees and 18 degrees), utilizing an automated geometric work station. Results indicated that, disregarding the signal mode, feedback had no effect on performance. However, when light was utilized as a mode of signal, results were superior at 0 degrees and 18 degrees angles when positive knowledge of results was provided. Work surface angle had little effect on performance efficiency, the 18 degrees angle being slightly superior to the 0 degrees and 9 degrees angles.