Liquid Chromatography coupled to Ultraviolet-Visible (HPLC-UV)
High resolution liquid chromatography (HPLC) is one of the most widely used separation techniques, due to its versatility and broad field of application. Chromatography is essentially a physical method of separation, in which the components to be separated are distributed in two phases: the stationary phase, with a large surface area and the mobile phase, which runs continuously throughout the stationary phase. Chromatographic processes take place as a result of the repeated absorptions and desorptions during movement of the sample components throughout the stationary phase, achieving separation of the same according to their distribution coefficients. The final outcome is that the components of the mix come out separated depending on their retention times, which constitutes the chromatogram. Through the chromatogram it is possible to identify the separated substances qualitatively and quantitatively.
The field of application for this technique is very wide-ranging. Some of the applications are listed here:
- Determination of organic pollutants (pesticides, herbicides, phenols, PCBs)
- Pharmaceutical products (antibiotics, sedatives, painkillers)
- Foodstuffs: artificial sweeteners, antioxidants, additives
- Quantitative analysis of compounds of interest
The HPLC Model 1200 (Agilent Technologies) apparatus includes a vacuum degasser, quaternary pump, automatic injector, thermostatted column compartment and diode detector (DAD).
Ion Chromatography is a variant of High Performance Liquid Chromatography (HPLC). Separation and determination of ions is carried out, based on the use of ion exchange resins. This type of chromatography is subdivided into cation and anion exchange chromatography, with the latter featuring most applications.
With detection by conductivity.
- Anion analysis (F-, Cl-, NO2-, Br-, NO3-, PO43-, SO42-) in aqueous matrices
- Cation analysis (Na+, NH4+, K+, Mg2+, Ca2+) in aqueous matrices
Dual channel Ion Chromatography system model 861 Advances compact IC (Metrohm), with sequential chemical suppression and samples ultrafiltration. Simultaneous determination of anions and cations with conductivity detector
Inductively Coupled Plasma Mass Spectrometry
The analytical technique with the greatest potential for determination of trace level elements in all types of matrices. It is usually necessary to perform a sample digestion. The liquid sample is introduced through a misting system and transformed into a fine spray which is directed towards the torch where a plasma is generated, whose temperature can reach up to 10,000 K, by submitting a flow of argon gas to the action of an oscillating magnetic field induced by a high frequency current. The sample is subjected to various processes (desolvation, vaporisation, atomisation and ionisation). The ions generated pass into the mass spectrometer through a conditioning interface, where they are focused and aimed towards the analyser, usually quadrupole type, where they are separated according to their mass/charge ratio (m/z).
- The majority of elements in the periodic table can be analysed using this technique
- Semi-quantitative multi-element analysis. To determine the major and minor elements in a sample. Allows semi-quantitative determinations of elements for which there is no commercial standard with an error lower than 15%
- Quantitative analysis of elements of interest Linear dynamic range of 8 orders of magnitude (ng/L (ppt) – mg/L (ppm) and low detection limits (ng/L (ppt) for most elements
- Gauging the isotopic ratios of an element
- Analysis of small sampling volumes (< 600 uL)
- Analysing solid biological, organic and inorganic samples by acid digestion and microwave treatments
- Environmental applications (waters, soils, sediments and residues)
- Determining metals and possible contaminants in soils (fertilisers) and inland drinking waters (dumping)
- Speciation of metals in complex matrices
- Quantification of inorganic nanoparticles
Inductively coupled plasma - mass spectrometer (ICP-MS), model 7700 x (Agilent Technologies). High levels of performance, reliability and automation. Includes a collision cell system in helium mode; greater sensitivity, less background noise, increased removal of spectral interferences and ‘no gas’ mode. Option of coupling separation techniques such as high performance liquid chromatography (HPLC).
Mass Spectrometry Unit
Mass Spectrometry (MS) is a highly sensitive instrumental analytical technique able to quali- and quantitatively assess all types of mixtures of substances. In addition, this technique also determines the molecular mass of a compound, as well at the different fragments resulting from controlled break-up of the same, providing highly valuable information on the molecular structure. Mass Spectrometry is a powerful analytical technique based on the different behaviours of the ions formed by different ionisation techniques when passing through electrical and magnetic fields. The ions are separated according to their mass/charge (m/z) ratio and detected.
The great advantage of high-resolution mass spectrometry compared to low resolution is the greater precision and accuracy of the mass, due to the more high-performance features of the time of flight-quadrupole analysers (TOF and QTOF). These allow unequivocal identification of the exact mass of a compound.
The laboratory analyses the different types of organic/inorganic contaminants in line with current regulations on maximum residue limits. The following features are highlighted:
- Analysis of organic micropollutants in waters by GC-MS/MS (organochlorine and organophosphorus pesticides, trihalomethanes, polyaromatic hydrocarbons) by means of LC-MS(TOF) y LC-MS/MS(QTOF) (drug and multi-residue).
- Determination of impurities in pesticide products.
- Assays to determine exact mass and fragmentation studies.
- Identifying compounds, or fragments of the same, by their mass spectrum in comparison with GC-MS libraries.
New analytical methods are constantly being developed to adapt to the new requirements laid down in current legislation on monitoring water quality and control parameters.
|Bidimensional Gas Chromatography/ MS (GC x GC/TOF). Pegasus 4D GC x GC TOFMS (LECO) and GC model 7890A from Agilent Technologies.||Gas Chromatography / Triple Quadrupole (GC-MS/MS (QqQ)). GC model 7890A and triple quadrupole detector model 7000 (Agilent Technologies). This system is coupled to a Gerstel twister brand Autosampler (MultiPurpose Sampler model 2XL).|
|Liquid Chromatography /Triple TOF (LC-QTOF) equipment. Triple TOF 5600 model (AB sciex).||Liquid Chromatography /MS (LC-TOF) equipment (Agilent Technologies).|
Basic Analysis Unit
In this unit we analyse several physical and chemical parameters laid down in the regulations on control of water quality and dumping.
- Organoleptic assays: Colour and turbidity
- Physical-chemical testing: Basic parameters such as pH, conductivity, temperature, redox potential, TKN (Total Kjeldahl Nitrogen), total phosphorus, free and total chlorine, alkalinity, suspended solids (TSS), total organic carbon (TOC), DBO5, DQO, total nitrogen, etc.
|Particle counter for water samples. This equipment is able to count particles of sizes ranging between 0.2 microns and 2 microns. LS_200 model from Particle Measuring System Inc.||Visible UV spectrophotometer. Measurements at different wavelengths and obtaining Vis-UV spectra of compounds (190-1.100 nm). UV-1800 model from Shimadzu.Espectrofotómetro UV-Visible.|
Total Organic Carbon (TOC) Analyser. TOC-V CSH model. Shimadzu brand.Analizador de Carbono Orgánico Total (TOC).