Perchloric acid eluent solutions

Acid eluents serve a dual function. First, the acid will protonate the amine so that the amine will interact with the resin and the hydrogen ion will serve as the exchange ion in the chromatographic process. The eluent suitable for the separation of aromatic amines is an aqueous perchloric acid solution. Other mineral acids can also be used but may form complexes with metals in the sample or the chromatograph or oxidize components of the sample., ... 

A series of perchloric acid solutions were prepared as the eluent. Each eluent was flushed through the chromatograph until a stable baseline was obtained. Each individual amine was injected onto the column using the 0.5 ml sample loop. The amine was allowed to elute if possible. If after sixty minutes the amine had not eluted, the system was flushed with 1 M HCIO4 to remove the compound. The order of elution of the amine and the effect of eluent concentration on the retention time were determined. 

Because of the cobalt(II) contamination, the perchlorate salt is synthesized and then converted to other salts. Cobalt(II) chloride 6-hydrate (1.0 g, 4 mmole) and free [15]aneN4 (05 g, 4.2 mmole) are warmed in 100 mL of methanol for 15 minutes. Concentrated hydrochloric add is added dropwise (1 mL) and air is bubbled through the solution for at least 2 hours. Several drops of perchloric acid are added to precipitate the products as the perchlorates. The yield is 72%. The product is brown and is about 90% pure isomer I. The brown perchlorate salt is dissolved in acetonitrile and passed through a Dowex 1X8,200-400 mesh anion exchange column (Cl form) at a rate of 10 sec/drop. The eluent is concentrated by rotary evaporation. Some green solid (isomer II) precipitates. This is filtered and the volume of the filtrate is further reduced to precipitate the tan isomer (I) as the chloride salt. Yield 60% Anal. Calcd. for CoC2r H26N4a3 C, 34.80 H, 650 N, 14.76. Found C, 34.35 H, 7.09 N, 14.50. 

A 1-g portion of the modified catalyst was washed with THF (two 10 cm portions), methanol (two 10 cm portions), and distilled water (two 10 cm portions). The catalyst was suspended in 15 cm of a 1 mol dm NaOH solution at 373 K to remove the tartaric acid from the surface to the solution. The supernatant was collected by decantation, and the remaining catalyst was washed three times with lOcm water. After the combination of the supernatant and the washings, the solution was filled to 50 cm with water. The amormt of tartaric acid was determined by an ion chromatograph equipped with a Shodex KC-811 (8 mm ID X 300 mm) at 313 K. The eluent 1 mmol dm perchloric acid. 

Aqueous salt solutions are corrosive to stainless steel, especially at low pH. When aqueous acetic acid solutions are used as eluent, attention must therefore be paid to corrosion of the HPLC system. However, some salts, such as sodium sulphate, sodium nitrate, sodium acetate and sodium perchlorate, cause little corrosion of stainless steel even at low pH. Accordingly, these salts are a good choice for use together with acetic acid. Salts containing... 

The compound hydrolyzes in aqueous solution to form EtHg and thiosalyci-late that is an effective bactericide. Fast analysis of EtHg in less than 4 min can be performed using a bifunctional lonPac CS5A in the microbore format with an eluent consisting of lOmmol/L sodium perchlorate, lOmmol/L acetic acid, and 10 mmol/L cystine at a flow rate of 0.5 mL/min. 

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