A validated non-compendial method for determination of haemodialysis concentrate’s contents and its comparison with compendial method: Application of ISO 13958:2014 standard

Background: Haemodialysis is a process to remove the waste products and excess fluids that build up in the human body when kidneys stop working. Haemodialysis concentrate consists of two parts, acid concentrate (Part A) that contains mineral ions (Na, K, Mg and Ca) and buffering agent acetic acid /citric acid whereas basic concentrate (Part B) comprise of sodium bicarbonate alone or in combination with sodium chloride. Aim: Present research aimed to develop and validate a rapid method for determination of cations and anions in haemodialysis concentrates in solution and powder form by choosing one of technique among various suggested in ISO 13958:2014. Method: The analysis was done by flame emission (flame photometer), atomic absorption spectrometer (AAS), polarimetric and titrimetric techniques. ICH guidelines were followed for method validation by addressing the linearity, accuracy, precision and detection limits (LOD and LOQ). Results and Discussion: The calibration curves were linear for Mg, Ca, K and Na with coefficient of determination (R2 ) ≥ 0.9978 and regression data indicating the excellent linearity for the selected concentration range for each content. The recovery results were obtained between the ranges 96.9-102.5 % which were good enough to justified the suitability of proposed method for its intended applications. Statistical analysis indicated that there was no significant difference was observed between proposed and compendial method at 95 % confidence of interval. Conclusion: The advantage of proposed method over the compendial method by virtue of its economy and fast with reliable results because more reagents and chemicals are consumed in compendial method.

Levels of macroelements and toxic elements in herbal teas

A total of 14 diverse herbal teas were examined, including: yarrow, basil, St.John?s wort, peppermint, horsetail, nettle, thyme, corn silk, hibiscus, marshmallow, chamomile, rosehip, heather and wild mint. The samples were prepared using the method of microwave digestion, and measurements were performed by the use of inductively coupled plasma mass spectrometry (Cd, Hg, Pb, As, Sb); atomic absorption spectrometry (Mg); emission flame photometry (Ca, K, Na) and spectrophotometry (P). Intervals of variation (mg/kg) for macroelements were: Ca (2738-35399); P (1545-6264); Mg (1647-7816); Na (293-10629) and K (9683-33985), and for toxic elements: Cd (0.014-0.645); Hg (<0.001- 0.017); Pb (0.064-1.340); As (0.030-0.544) and Sb (0.004-0.068). In the three samples (yarrow and two St.John?s wort samples) measured cadmium concentration was higher than the maximum level for dried herbs, recommended by WHO. Ward's hierarchical clustering method was performed with the aim of grouping herbal teas by the amount of toxic elements.

Aspect Ratio Effects of Elliptic Co-Flow on Turbulent Jet Flame Structures

The aspect ratio effects of elliptic co-flow on the structure of a turbulent propane diffusion flame from a circular tube have been presented. Pollutant emission, flame radiation, flame structure, and soot concentration have been measured. The fuel jet exit Reynolds number is 2700, and the exit Reynolds number for the co-flow is 4010 and 8025 based on the minor and major axis respectively. The results are compared with the measurements from the experiments in a circular co-flow, which is the baseline condition for the present study. The pollution characteristics and the structure of the flame in the elliptic co-flow are significantly different from those in the circular co-flow. The NO emission is higher and the CO emission is lower in the elliptic co-flow. Elliptic co-flow flame produces less soot than circular co-flow flame. The study shows that the elliptic co-flow aspect ratio has a controlling influence on various combustion characteristics. In general, it is seen that as the aspect ratio of the elliptic co-flow is increased from 2:1 to 4:1, the entrainment of air increases and thus the combustion characteristics are enhanced. Compared to 2:1 AR co-flow flames, the flames with 4:1 AR co-flow are more stable, have a lower flame height, produce more NO and less CO, the flame peak temperature is higher, are less sooty, and radiate less. Flame spectral measurements show that the 4:1 aspect ratio flames produce more OH, CH, C2 and H2O radicals in the near-burner region than the 2:1 co-flow flames as a result of higher fuel oxidation.

Na+ and K+ cell concentrations in collagenase-treated rat kidney tubules incubated at various temperatures

Na+ and K+ cell contents were measured in single pieces of tubule (0.4–0.8 mm/sample) micro-dissected from the outer medulla of collagenase-treated rat kidney tissue. Extracellular cations were washed out by rinsing the tubules in ice-cold choline-chloride solution. Na+ and K+ cell contents were measured by emission flame microphotometry after appropriate treatment of the samples. Tubular volumes were calculated from photographic pictures taken before (at 4 degrees C) and after incubation of the samples. Medullary collecting tubules (MCT) and medullary thick ascending limbs of Henle (MAL) were used in this study. When kept at 4 degrees C for 2 h or more, Na+ and K+ concentrations (meq/l cell volume) were 86.3 and 30.6, respectively, in MCT and 16.2 and 94.3, respectively, in MAL. After about 5 min of incubation at 30 degrees C, MCT samples inverted their cation contents up to new steady-state concentrations (Na+ 17.4 and K+ 97.5). During incubation, the volume of MCT samples decreased slowly and in an exponential way, the rate of which was highly temperature dependent. Na+ and K+ cell concentrations in such incubated MCT samples, however, remained fairly constant between 20 and 37 degrees C. In contrast, when MAL samples were incubated at 30 degrees C, Na+ and K+ concentrations (15.9 and 90.4, respectively) remained equal to those measured at 4 degrees C and no change in volume was observed in MAL samples.

Comparison of Nebulization-Spray Chamber Arrangements for Atomic Fluorescence and Atomic Emission Flame Spectrometry

Ten different commercial atomic absorption nebulizer-chamber systems with a capillary burner and three laboratory-constructed ultrasonic nebulizer chamber systems with a miniflame burner are compared with respect to solution uptake rates, concentrational and absolute detection limits, efficiencies of nebulization, and common flame spectrometric interferences. Measurements of both flame atomic emission (Sr, Ca, K, Na) and flame atomic fluorescence (Mg, Cu, Pb) were performed for all cases. The ultrasonic and pneumatic nebulizer systems resulted in about the same concentrational detection limits, but the former resulted in ∼102X lower absolute detection limits. The batch type ultrasonic nebulizer gave much higher nebulization efficiencies than the continuous flow ultrasonic nebulizer or any of the pneumatic nebulizer systems. Chemical interferences were approximately the same in all nebulizer-burner systems. Nebulizer chambers with a J-bead resulted in lower detection limits than the same systems without J-beads.