Determination Of Pharmaceuticals In Waste Waters Biology Essay

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We are interested in screening of pharmaceutical compounds in wastewater using different detection techniques. Pharmaceutical compounds have become a source of increasing environmental concern as their use in recent days has increased drastically, and there is a great possibility that they enter the hydrologic systems. The pharmaceuticals in wastewaters have potential adverse impacts such as water quality degradation, endocrine disruption (mental, physical, sexual development), and antibiotic resistance public perception. Research has been done to identify the presence of twenty pharmaceuticals in wastewater coming from two Oslo Hospitals. The stunning conclusion was that seventeen of these toxins are actually present in the waste water. Later on after purification, these chemical components were still detectable in the water along with seven drug metabolites. By this they came to know that the waste water treatment works are unable to filter out pharmaceutical drugs, on the other side, their was a hypothesis that they may also be responsible for toxic substances left in the purified water.The potential risk of pharmaceuticals should be monitored carefully with more reliable techniques, because many uncertainties still exist in the determination and toxicity of metabolites in water environments.

Methods were used to detect pharmaceutical components in water are namely solid phase extraction, high performance liquid chromatography and mass spectrometry. A range of pharmaceutical compounds exist in wastewaters may be reliably detected and characterised by chromatography and mass spectrometric techniques using appropriate extraction methods. Our main aim is to perform extraction methods to isolate compounds of pharmaceutical interest from wastewaters. Develop tandem and multiple stage mass spectrometric methods for the characterisation of these drugs and metabolites. Using methods like Solid phase extraction, chromatography, quadrupole time of flight and ion trap mass spectrometry are performed and is evaluated for the analysis of different drug cocktails in wastewaters. We assume that these methods of detection are reliable screening methods for pharmaceutical compounds in Northern Ireland municipal wastewaters. The Pharmaceutical compounds in wastewaters that were previously detected by researchers which were in the highest concentration in this entire research were caffeine, ibuprofen and bezafibrate`

INTRODUCTION:

Pharmaceutical compounds have become a source of increasing environmental concern as their use in recent days has increased drastically, and there is a great possibility that they enter the hydrologic systems. Research has been done to identify the presence of twenty pharmaceuticals in wastewater coming from two Oslo Hospitals. The stunning conclusion was that seventeen of these toxins are actually present in the waste water. A further examination of the waste water flowing into the water treatment works was done and again twelve pharmaceuticals were found.(Herremans.D.,2007)

In an earlier study during 1999 and 2000, researchers in the United States collected water samples from 139 streams across 30 sites. Sampling sites were mostly from streams susceptible to contamination. All of these samples were analyzed to identify 95 Organic waste water contaminants. It was found that 80% of these streams contained organic wastewater contaminants. The compounds detected were from a wide range of residential, industrial and agricultural origin. This study has shown that some of the compounds such as caffeine, ibuprofen and bezafibrate were generally identified. But all these identified compounds are depended on the location and type of industries releasing them. The concentrations were generally low and rarely exceeded drinking-water guidelines, drinking-water health advisories, or aquatic-life criteria, but however most of the compounds do not have such guidelines established. Multiple organic wastewater contaminants were commonly found from this study, with a median of seven and as many as 38 organic waste water contaminants being found in any given sample of water. Little is known about the adverse effects (such as synergistic or antagonistic toxicity) that may occur from complex mixtures of organic wastewater contaminants in the environment. The results from this study demonstrate the importance of obtaining data on metabolites to fully understand not only the fate and transport of organic wastewater contaminants in the hydrologic system but also their ultimate overall effect on human health and the environment.(Koplin et al., 2002)

The analytical determination of pharmaceutical compounds in waste water is performed by Solid phase extraction which is highly sophisticated method for isolating and concentrating solutes from relatively large volumes of liquid. This technique can be very effective, even when solutes are present at very dilute concentrations (e.g. ppb). Materials extracted in this way can be used for subsequent chromatographic separation, spectroscopic examination, or biological assessment. The ion-trap mass spectrometer is excellent equipment for identifying various chemical compounds. The benefits of the ion-trap mass spectrometer include compact size and the ability to trap and accumulate ions to increase the signal-to-noise ratio of a measurement. (scott., 2000)

Methods:

Solid phase extraction, chromatography, quadrupole time of flight (QTOF) and ion trap mass spectrometry

Methodologies:

Several methods has been developed to determine eleven pharmaceutical compounds in different water samples .These methods are SPE and HPLC coupled to MS (LC/MS) using ESI in both positive and negative modes. Three different sorbents were compared for the extraction of analytes from river and sewage treatment plant waters and OASIS HLB provided the best results.

The apparatus used consists of a simple tube, which may be 2-4 mm I.D and 2-4 cm long and may be made of stainless steel or a suitable inert polymer. The extraction tube is usually packed with a bonded phase. Long chain hydrocarbon bonded phase is used as this is most effective for extracting dispersive materials from water (e.g. hydrocarbons, chlorinated hydrocarbons, pesticides, etc) .If necessary, this system can be used to extract many liters of water, and all the solutes accumulate at the front of the packing .Methanol or acetonitrile (0.5-1ml) is used to displace the solutes from the absorbent(usually by reverse flow techniques to minimize extract dilution) .A concentration factor of two thousand to four thousand from the test results indicates that by selection of a right adsorbent the extraction process can be very efficient e.g. greater than 99 percentage. The choice of adsorbent can be quite critical. In contrast to the above extracting process, polar materials (e.g. alcohol) can be removed from dispersive solvents (e.g. gasoline) using silica gel as the adsorbent, the alcohols being held on the adsorbent by strong polar interactions with the silica gel hydroxyl groups .The solutes might be desorbed with acetonitrile or an acetonitrile water mixture.(Bones, Thomas & Paull., 2007)

(Anonymous)

Chromatography:

LC/MS analysis uses a Waters Alliance HPLC coupled to a Waters Quattro Premier triple quadruple mass spectrometer. Analytes were separated on a Luna 5μ, C18 column (Phenomenex; 250 x 2 mm) with guard column. The mobile phases used for positive ion mode detection were water and modified methanol (20 mM ammonium acetate), and in negative mode water and methanol were used. A simple gradient elution from 5% to 95% organic solvent over 20 minutes separated all compounds. The first 4 minutes of the HPLC run were sent to waste to ensure high sensitivity throughout the run. (Hartig, Storm & Jekel., 1999)

Mass Spectrometry:

Mass spectrometer is an instrument which is used to isolate chemical compounds according to their mass to charge (m/z) ratio of ions in which magnetic field is applied, and presence of ions can be recorded with respect to relative abundance (%) and time (min). The word intensity is used with respect to the height of a peak or the strength of an ion beam. Mass spectral peaks can also display profiles with width as well as height. In GC/MS or LC/MS, care should be taken to differentiate mass spectral and chromatographic peaks. The most intense peak in a displayed mass spectrum is the base peak. Each mass spectral line represented by a single line or profile data plot of the intensities observed at each acquired mass to charge ratio. The mass spectrum can be displayed in a normalized or non-normalized table of m/z values and intensities. (Sparkman 1942)

Overall Aim: The analytical determination of pharmaceutical compounds in wastewaters.

Governing Hypothesis:

A range of pharmaceutical compounds exist in wastewaters which may be structurally characterised using tandem mass spectrometric technologies.

Specific Aim 1: To develop solid phase extraction methods to isolate compounds of pharmaceutical interest from wastewaters.

Background/Introduction:

The solid-phase extraction of five hundred mL of drainage water samples, the recoveries were 41 to 101% with the three exceptional drugs namely acetaminophen, salicylic acid and naproxen. The LODs were in between 3 and 5 ng/L for all of the compounds, except naproxen which had an LOD of 15 ng/L. Acetaminophen, caffeine, carbamazepine, bezafibrate and ibuprofen were found in three of the tested river samples at ng/L levels The compounds detected were from a wide range of residential, industrial and agricultural origin. The results from this study conclude that the concentrations were generally low and rarely exceeded drinking-water guidelinesand among these; the highest values were for caffeine and bezafibrate with 305 and 363 ng/L, respectively. For the influent and effluent water samples of the STP, volumes of 100 and 250 mL were used, respectively, to obtain acceptable recoveries. All the compounds showed recoveries between 33 and 91% for effluent samples and 33-72% for influent samples, with the exception of acetaminophen, salicylic acid and bezafibrate, which had lower recoveries. The method developed enabled pharmaceuticals in the influent and effluent sewage waters to be determined in five campaigns carried out between February 2004 and June 2005. Several pharmaceuticals were found in the influent samples: for instance, maximum concentrations of ibuprofen and caffeine were 6 and 40 µg/L, respectively. (Marta et al., 2007)

Planned Research: In this research we are going to perform extraction of pharmaceutical compounds from waste water collected from Northern Ireland municipal and pharmaceutical industrial waste water .This is done using solid phase extraction and the extract is analysed for the drug content using ion trap MS method.

Expected Difficulties & how they can be solved:

Difficulties would be if the solid phase extraction method was not efficient in extracting drugs etc from the wastewaters. This would be overcome by spending time on method developing the SPE part.

Expected Outcomes: Elution of pharmaceutical metabolites probably may be collected for further analysis

Specific Aim 2: To develop tandem and multiple stage mass spectrometric methods for the characterization of drugs and metabolites in wastewater in conjunction with database searching.

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Background / Introduction:

The quadrupole ion trap is an extremely useful in many ways, yet relatively cheaper priced mass spectrometer. The sensitivity and performance of the instrument, especially the automated experiments developed for the newly commercialized ion traps, make quadrupole ion trap mass spectrometry a special and suited technique to apply to the analysis of biological and biochemical complications.A hybrid tandem mass spectrometer is built by interfacing a quadrupole mass filter (Q) to a quadrupole ion trap mass spectrometer (QITMS) and is evaluated for the analysis of mixtures. The mass filter is set to selectively inject ions of a particular m/z or, in scanning mode, to sequentially inject ions into the QITMS for subsequent manipulation and detection.(Karen, John 1996)

High performance liquid chromatography coupled to mass spectrometry (HPLC-MS) and mainly tandem mass spectrometry (HPLC-MS/MS) have been the major source of analytical technique used to determine ultratrace concentrations of pharmaceuticals in wastewater. The long term procedure performance of HPLC/MS and HPLC/MS/MS for usual monitoring of environmental pharmaceutical concentrations has not been described before. An analytical method has been developed allowing for simultaneous detection and identification of 20 pharmaceutical compounds from different therapeutic classes using solid phase extraction (SPE) followed by liquid chromatography-electrospray ionisation mass spectrometry (LC-MS/MS). Fragmentation profile of compounds can be observed using MS/MS characterization. The limits of detection and limits of quantitation for the method were in the ng/L-microg/L range. The method was applied to influent and effluent samples from three wastewater treatment plants (WWTPs). Fifteen compounds were detected in the sample matrix with salicylic acid and ibuprofen being the most abundant at 9.17 and 3.20 µg/L respectively.(Lacey et al., 2008)

Planned Research: In this research I prefer to use LC/MS because GC can only identify volatile substances. Wastewater samples we obtained will be investigated using HPLC MS/MS techniques to determine the pharmaceutical metabolites.

Expected Difficulties & how they can be solved: Some of the difficulties here will be in the identification of all of the compounds that will elute in HPLC.Database searching using the NIST database will help to correlate experimental MS/MS profiles to those already generated and deposited in databases. This will assist towards identification of parent drugs or metabolites.

Expected outcomes: Known drug standards could be spiked into the wastewaters and then the recovery values are measured.

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