Naslov
Određivanje i validacija cijanida u vodi ionskom kromatografijom
(Determination and validation of free cyanide in water by ion cromatography)

Autori
Kosić-Vukšić, Josipa

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts / Bolanča, Tomislav ; Ukić, Šime - Zagreb, 2016, 12-13

Skup
16th International Chromatography School

Mjesto i datum
Zagreb, Hrvatska, 09.06.2016. - 10.06.2016

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Slobodni i ukupni cijanidi, analiza voda, ionska kromatografija, validacija
(Free and total cyanide, water analysis, ion cromatography, validation)

Sažetak
Cyanide is one of the most toxic inorganic substances. It is emitted into the environment mainly with industrial waste water. Its presence in concentrations higher than allowed one is a potential threat to the human health. Cyanide is classified according to its availability in the presence of complexing metals. Total cyanide refers to cyanide which can be released as hydrocyanic acid from the aqueous sample under total reflux distillation conditions and includes both free and total complex cyanides. Free cyanide refers to cyanide which can be released as hydrocyanic acid from the aqueous portion of a sample by direct cyanide determination without reflux distillation. In Croatia, the maximum allowed value for free cyanide in waste water is up to 100 µg/L, for total cyanide up to 500 µg/L, in water for human consumption maximum level for total cyanide is 50 µg/L. A number of procedures for the determination of cyanide have been proposed (titration, colorimetric and polarographic techniques, ion-selective electrode). In this paper, analysis of free cyanide in waters wass carried out by using ion chromatography (Compact IC, Metrohm AG, Switzerland) with electrochemical detector (amperometry), working electrode (Ag), and reference electrode Ag/AgCl. Used column was Metrosep A Supp 1 (250 × 4.6 mm) and the corresponding pre-column was commercially available from Metrohm. The column packing was polystyrene/divinylbenzene copolymer, particle size 7 µm. The volume injected, the flow rate and the temperature were set at 20 µL, 1.0 mL/min and 25 °C, respectively. The eluent was 100 mM NaOH (pH 12.8). Retention time of cyanide was 6.5 min. Water samples should be stabilized immediately with sodium hydroxide (adjust pH above 12), cooled to 4 °C, before injection filtered through a membrane filter pore size 0.45 µm. The method was validated ; validation parameters were studied in terms of linearity, precision, trueness, LOD and LOQ. The linearity of cyanide response was determined by measuring three replicates of seven standards (1, 5, 10, 50, 75, 100, 200 µg/L). The 16TH INTERNATIONAL CHROMATOGRAPHY SCHOOL 13 International Chromatography School calibration results showed good linearity (r > 0.999). RSD of repeatability was below 1 % and RSD of inter-day precision for standard was below 3 %. Mean recoveries from 100.7–104.5% were obtained for samples spiked with cyanide over the range of 45–125 µg/L. Limits of detection and quantification were 0.5 and 1.4 µg/L, respectively. Method could also be applied for determination of total cyanide but with appropriate modification to the standard reflux-distillation procedures.

Izvorni jezik
Engleski

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