Fusion blank

The reagent blank can be used as an indication of the baseline Instrumental detection limit, when its standard deviation is multiplied by the appropriate constant. Data from this solution could be used to answer question 1 above, but in a number of cases cannot be used to answer the second question. The analytical blanks can be used as indications of method detection limits, wherein wet ash digestion or alkali fusion procedures are employed to dissolve the sample. In the case of the fusion blank, this analytical blank also serves as a specific type of matrix blank since the principal constituents in solution are lithium and boron. The concentrated iron and aluminum solutions represent solution matrices that contain the major constituent when the determination of trace elements in these matrices is of concern. These solutions can be used for answering question 2 above. In addition, these blanks also serve as analytical blanks since dissolution procedures were employed in their making. In some cases the differences in calculated detection limits among these solutions is significant."... 

Element A (nm) 1% HNO3 Fusion Blank Steel Blank Fe A1... 

Vorschlag, m. proposal, proposition (Metal.) fusion, fiux blank space on the first page of a book. 

Abbasi [234] has described a spectrophotometric method employing N-p-methoxyphenyl-2,-furohydroxic acid for the determination of titanium in soils. In this method, the soil sample was subjected to alkali fusion. The ash was treated with nitric acid to adjust it to pH 2.0 and filtered prior to adjustment to 10 pM with respect to hydrochloric acid. Stannous chloride (5M) was added to the filtrate, and the chromogenic reagent was dissolved in chloroform. The chloroform extract was evaluated spectrophotometrically at 385 nm against the reagent solution as blank. Approximately 61 ppm of titanium was found in a soil sample by this method. 

Microfabrication was achieved by UV-lithography with a negative photoresist SU-8 2035 based on a nickel plate [163], By means of electroforming of the exposed and developed resist structure, a nickel mold was prepared (see Figure 1.182). By hot embossing, the final polymer mixer structures were prepared. Holes for fluid connectors were drilled. The microstructured substrate was joined with a blank polymer plate by thermal fusion bonding. 

The addition of fluxes increases the risk of raising the blank value, as a result of the amount of flux required for successful fusion. In addition, the final aqueous solution obtained from the fusion has a high salt concentration, which can cause difficulties in subsequent steps of the analysis. The high temperatures required for a fusion increase the danger of volatilization losses. 

The calibration is established from solutions prepared by diluting a solution of I 000 mg/1 of the element to be determined. When sample solutions are prepared using the fusion method, the reference solutions used for this analysis contain the same quantity of lithium metaborate as the sample solution. The origin of the calibration curve is determined by a blank test solution prepared in the same way as the standards, but without the element to be determined. 

Disadvantages of the fusion method are that some elements may be volatile at 900°C, the fusion reagent may cause contamination, and the presence of high amounts of dissolved solid content may not be suitable for trace analysis. Blanks of fusion reagents must also be prepared alongside samples. The fusion fluxes are expensive and give rise to spectral interferences and must be considered a last resort. 

This form is stable at temperatures up to 1033°, and fusion at 1080° for 4 honrs causes complete de-vitrification and it reverts to the soluble form. [Muller Blank Chem Soc 46 2358 1924, Dennis Laubengayer Chem Soc 47 1945 1925, Laubengayer Morton J Am Chem Soc 54 2303 1932, Schenk in Handbook of... 

Titrimetric determination The mannitol or glycerol acid-base titration procedure is applied to the dissolved sodium carbonate melt for the determination of milligram amounts of B2O3. A blank prepared from a glass that does not contain boric oxide should be subjected to the same procedure. There are certain interferences the effect of fluoride is eliminated by adding calcium carbonate to the fusion mixture lead and zinc can be filtered off after dissolution of the melt phosphate is precipitated by addition of iron(ni) chloride. The influence of some interference from such elements as aluminum or titanium can be eliminated by adding ethylenediaminetetraacetic acid (EDTA). 

---