Application of hydrocyanic acid vapor generation via focused microwave radiation to the preparation of industrial effluent samples prior to free and total cyanide determinations by spectrophotometric flow injection analysis.
← Research streamA focused-microwave procedure was developed to generate HCN vapor from industrial effluent samples for subsequent spectrophotometric flow injection analysis of free and total cyanide. Free cyanides required 5 min irradiation at 90 W (plus 5 min purge), while …
Study snapshot
Abstract
A sample preparation procedure for the quantitative determination of free and total cyanides in industrial effluents has been developed that involves hydrocyanic acid vapor generation via focused microwave radiation. Hydrocyanic acid vapor was generated from free cyanides using only 5 min of irradiation time (90 W power) and a purge time of 5 min. The HCN generated was absorbed into an accepting NaOH solution using very simple glassware apparatus that was appropriate for the microwave oven cavity. After that, the cyanide concentration was determined within 90 s using a well-known spectrophotometric flow injection analysis system. Total cyanide analysis required 15 min irradiation time (90 W power), as well as chemical conditions such as the presence of EDTA-acetate buffer solution or ascorbic acid, depending on the effluent to be analyzed (petroleum refinery or electroplating effluents, respectively). The detection limit was 0.018 mg CN l(-1) (quantification limit of 0.05 mg CN l(-1)), and the measured RSD was better than 8% for ten independent analyses of effluent samples (1.4 mg l(-1) cyanide). The accuracy of the procedure was assessed via analyte spiking (with free and complex cyanides) and by performing an independent sample analysis based on the standard methodology recommended by the APHA for comparison. The sample preparation procedure takes only 10 min for free and 20 min for total cyanide, making this procedure much faster than traditional methodologies (conventional heating and distillation), which are time-consuming (they require at least 1 h). Samples from oil (sour and stripping tower bottom waters) and electroplating effluents were analyzed successfully.
AI evidence extraction
Structured fields below were generated from the paper’s abstract and metadata to make the evidence easier to inspect. Automated extraction may be incomplete or incorrect; verify important details against the original paper.
Main findings
A focused-microwave procedure was developed to generate HCN vapor from industrial effluent samples for subsequent spectrophotometric flow injection analysis of free and total cyanide. Free cyanides required 5 min irradiation at 90 W (plus 5 min purge), while total cyanide required 15 min irradiation at 90 W with additional chemical conditions depending on effluent type; reported detection limit was 0.018 mg CN/L, RSD was better than 8% (n=10 at 1.4 mg/L), and results were assessed by spiking and comparison to an APHA-recommended standard method.
Outcomes measured
- Hydrocyanic acid (HCN) vapor generation efficiency for sample preparation
- Free cyanide determination in industrial effluents
- Total cyanide determination in industrial effluents
- Analytical performance: detection limit, quantification limit, precision (RSD), accuracy vs APHA method
- Sample preparation time vs conventional heating/distillation
View raw extracted JSON
{
"study_type": "engineering",
"exposure": {
"band": null,
"source": "focused microwave radiation (microwave oven)",
"frequency_mhz": null,
"sar_wkg": null,
"duration": "5 min irradiation (free cyanides) or 15 min irradiation (total cyanide); 90 W power"
},
"population": null,
"sample_size": null,
"outcomes": [
"Hydrocyanic acid (HCN) vapor generation efficiency for sample preparation",
"Free cyanide determination in industrial effluents",
"Total cyanide determination in industrial effluents",
"Analytical performance: detection limit, quantification limit, precision (RSD), accuracy vs APHA method",
"Sample preparation time vs conventional heating/distillation"
],
"main_findings": "A focused-microwave procedure was developed to generate HCN vapor from industrial effluent samples for subsequent spectrophotometric flow injection analysis of free and total cyanide. Free cyanides required 5 min irradiation at 90 W (plus 5 min purge), while total cyanide required 15 min irradiation at 90 W with additional chemical conditions depending on effluent type; reported detection limit was 0.018 mg CN/L, RSD was better than 8% (n=10 at 1.4 mg/L), and results were assessed by spiking and comparison to an APHA-recommended standard method.",
"effect_direction": "unclear",
"limitations": [],
"evidence_strength": "insufficient",
"confidence": 0.74,
"peer_reviewed_likely": "yes",
"keywords": [
"microwave radiation",
"focused microwave",
"industrial effluents",
"sample preparation",
"hydrocyanic acid vapor generation",
"free cyanide",
"total cyanide",
"spectrophotometric flow injection analysis",
"APHA method comparison",
"detection limit",
"RSD"
],
"suggested_hubs": []
}AI-extracted fields are generated from the abstract and metadata and may be incomplete or incorrect. This material is for informational purposes and is not medical advice.
Identifiers and source
DOI: 10.1007/s00216-006-0985-1
PubMed: 17143595