Airborne antibiotic concentrations in a swine feeding operation.

During the past 50 years, it has become common practice in the U.S. to add antibiotics to livestock feed to reduce disease and promote growth. Use of antibiotics in this manner has become the source of increasing controversy because overuse of antibiotics is suspected of leading to resistance in bacteria that cause human diseases. The purpose of this study was to measure airborne antibiotic concentrations in a swine production facility that routinely included antibiotics in feed. Samples were collected in a hog facility that included rooms devoted to farrowing, nursery, and growing operations. Analytical methods were developed to measure concentrations of the antibiotics tylosin and lincomycin in air samples. Tylosin was mixed in the feed in some of the rooms in the facility. While lincomycin was not added during this study, it had been used in this facility in the past and therefore was included in the analytical testing. Inhalable (n = 34), respirable (n = 37), and high-volume (n = 16) dust samples were collected on PVC filters over a two-month period. Tylosin concentrations were above the limit of quantification (LOQ) in 93% of the samples, while lincomycin concentrations were above the LOQ in only 9% of the samples (LOQ = 0.04 ng/sample). The average tylosin concentrations were 3, 18, and 49 ng/m3 in the respirable, inhalable, and high-volume samples, respectively. No occupational or environmental worker exposure criteria currently exist for antibiotics in air. The results of this study may be used to estimate potential swine production worker exposures and to further study the association between these exposures and health effects.

Determination of sulfonic acid degradates of chloroacetanilide and chloroacetamide herbicides in groundwater by LC/MS/MS.

An analytical method is presented which permits qualitative and quantitative analysis of sulfonic acid degradates of three chloroacetanilide herbicides (acetochlor, alachlor, and metolachlor) and one chloroacetamide herbicide (dimethenamid) in groundwater at trace levels with determination by LC/MS/MS. The analytes were isolated from groundwater by solid-phase extraction (SPE). The final samples were analyzed by reversed-phase HPLC with MS/MS detection utilizing a pneumatically assisted, and heat-assisted electrospray interface (TurboIonSpray). Unique precursor/production pairs were obtained in the MS/MS mode which permitted conclusive identification of each analyte, even when the analytes coeluted. Quantification was performed by generation of an external calibration curve. Excellent linearity was obtained over a calibration range from 0.25 to 10 ng injected on-column, with all linear correlation coefficients exceeding 0.999. Method performance for this analytical procedure was validated by analyzing groundwater samples fortified at levels of 0.1, 1, and 50 ppb. The average recovery at each fortification level for each analyte exceeded 89%. Excellent method precision was demonstrated with percent relative standard deviations of less than 10% for all analytes at all fortification levels.

Liquid chromatography in open tubes.

Liquid chromatography in open tubes is evaluated for applicability to clinical analysis. The principal advantages of this technique include high separation power, reduced solvent consumption, and small sample volume requirements. Technology for the production of columns as small as 8 micron (i.d.) is described. Preliminary results are encouraging and, with further development in column and detector technology, the technique should find wide applicability in clinical analysis.