What is wet chemical analysis?

Wet chemistry, also called bench chemistry or wet chemical analysis, is a form of analytical chemistry that uses methods, such as colorimetry, gravimetry and titration to analyze elements and compounds in liquid samples. Although analytical chemistry has evolved exponentially in last three decades, wet chemical analysis remains is an integral part of the modern analytical chemistry lab. Wet chemical methods are both proven and less expensive. Additionally, modern instrumentation cannot always get the results that specific wet chemical tests provide. Wet chemistry instruments include, pH/conductivity/ion meter, automated titrator, colorimeter, turbidity meter, spectrophotometer and flow injection analyzers (FIAs), segmented flow analyzers (SFAs) or continuous flow analyzers (CFAs).

Wet analysis methods

Well established, selective, colorimetric measurements are used in several automated analyses. Based on how the sample is mixed with the coloring reagents, an instrument can be classified as an FIA or flow analyzer, CFA, SFA or continuous segmented flow analyzer or autoanalyzer.

Traditional wet chemical methods can be labor intensive and time consuming. Additionally, they are usually applicable only to specific individual parameters. specific individual parameters. Testing for multiple parameters, therefore, requires multiple techniques and instruments that require long, hands-on-sample and response times, resulting in reduced throughput and increased cost per analysis. Significant investment in ongoing staff training and instrument maintenance are also required.

A discrete analyzer is an automated wet chemical analyzer that performs tests on samples kept in discrete cells. These innovative systems offer an automated, streamlined and more cost-effective approach to wet chemical analysis.

Thermo Scientific Gallery and Gallery Plus discrete analyzers, with ready-to-use system reagents, are optimized for speed, flexibility, and precision for wine, beer, malt, beverages, enzymes, soil, process water, ground water, wastewater, drinking water and nutrient analysis that enables improved quality control through consolidated testing.

Gallery discrete analyzers can automate labor-intensive and time-consuming multiparameter wet chemical analysis.

Automated discrete analyzers utilize colorimetric and enzymatic measurements of several analytes simultaneously from a single sample through photometric analysis. The discrete analyzer mimics the operation sequence of lab chemists such as dispense sample, mixing reagent, waiting for the reaction to complete, followed by photometric measurement, to provide fast and reproducible results. Discrete analyzers consist of three components, a Photometer with specific number of filter positions, dispensing probes, an incubator to control the reaction temperature, a mixer. In discrete analysis, each individual reaction cell is isolated, and temperature is stabilized, enabling highly controlled reaction conditions.

How automated Discrete Analyzer works

After the reagents and samples are prepared, they are loaded onto the instrument and the probes dispense fixed amounts of reagents and samples into the individual cuvettes. Next, the individual cuvettes are loaded into the incubation chamber, samples and reagents dispensed to the individual cuvettes and then mixed, and finally undergo photometric detection depending on the absorbance of specific wavelengths of light. Each measurement is done using single discrete cuvettes. These data are then interpreted through integrated software platforms.

Advanced discrete analyzers use disposable cuvettes that eliminates the carry over effect and reduces the reagent consumption substantially. Number of wet chemical parameter a discrete analyzer can perform is limited by the number of filter positions and the wavelength range.

Discrete analyzer consolidates and simultaneously tests for up to 20 different wet chemical parameters — using a single instrument with a single operator. Discrete analyzer, with miniaturized components and unique low-volume cuvette design, accommodates small reagent volumes, minimizes reagent waste, and as a result, reduces analysis cost.

Why operate multiple analyzers, when you can do all your essential testing with one? Thermo Scientific™ Gallery™ and Gallery™ Plus discrete analyzers are easy to use, automated systems that allow laboratories to simplify their testing with the dual benefits of time and cost savings. All necessary analysis steps are automated, providing true walk-away time for the operator. It is a fully integrated walkaway solution: the testing workflow is easy to learn, and can be left unattended, improving throughput, system uptime and staff productivity. Gallery and Gallery Plus discrete analyzers automate manual wet chemistry methods, photometric (colorimetric and enzymatic), and electrochemical (pH and conductivity) analysis, mimicking the operation of lab chemists, to provide fast, reproducible results in a compact design.

While traditional analysis requires multiple wet chemistry methods and, therefore, multiple samples, the Gallery discrete analyzer consumes a maximum of 300 μL of sample per test, can test for up to 20 parameters per sample, and runs up to 200 tests per hour. As a result, the cost per analysis is 10 to 20 times less than traditional wet chemistry methods.

FeaturesGallery/Gallery Plus discrete analyzersFIA/SFA/CFA
Instrument typeFully integrated discrete analyzerOpen and modular type
Operator skill levelLowAdvanced
Number of measuring channelsFreely selectable 12 filter positions (channels)Maximum 4-6 channels; Need two 2 to 3 instruments to match channel capabilities
Sample sequenceRandom access — parallel and batch: sample can be loaded for several tests while a calibration for another is being processedMedium to high; impacts results reliability; requires intense maintenance to minimize carryover
Cross contaminationMinimal — discrete, fully disposable reaction cellsMedium to high; Impacts results reliability; requires intense maintenance to minimize carryover
Method stabilityVery high; long calibration stability and reproducible resultsLow; detector signal drifts; adjust data due to baseline drift throughout a batch run
Reagent deliveryFully automated micro liquid handling; robust systemPeristaltic pump; requires frequent maintenance
Number of tests/hr200-35060-120
Number of chemical parameters/sampleUp to 20 different chemical parameters for a sampleTypically, from 2 to 5; limited by number of channels
Reagent consumptionVery low (μL) Typically <100 μLLarge (mL) 8-10 mL
Instrument startup time<5 minutes15-45 minutes
Change over time between chemistriesNone15-30 minutes
Source lampLong life Xenon; savings on consumable cost over the instrument lifetimeTungsten. Requires frequent change
Number of reagents addition per testsMaximum four + a matrix matching reagent; easy to transfer FIA, SFA or CFA methodsTypically 2 reagent additions per test
ReagentsReady to use system reagents kits or in-house reagentsIn-house reagents
pH & conductivityElectrochemical Unit (ECM) moduleAdditional 2 channels

What is a flow injection analyzer?

A typical Flow Injection Analyzer (FIA), Continuous Flow Analyzer (CFA), or Continuous Segmented Flow Analyzer (SFA) system consists of an Autosampler, a peristaltic pump, a chemistry manifold, a photometric detector and data acquisition software. This setup is commonly referred as a channel or chemistry manifold. The number of wet chemical parameters a flow analyzer can handle is limited by the number of channel or chemistry manifold.

What are the advantages of FIA, SFA, and CFA over discrete analyzers?

Flow analyzers are ideal when a larger number of samples are to be analyzed for a smaller number of chemistries. Continuous Flow Injection analyzers, being modular, can add additional sample preparation blocks for difficult sample matrices. Some of the FIA, SFA, and CFAs can perform inline heating, distillation, dialysis, filtration and digestion. Users could change the measuring pathlength to enhance detection limits.

What are the advantages of discrete analyzers overflow injection or Segmented Flow analyzers?

Major advantages discrete analyzer over FIA or SFA are the number of parameters per sample that a discrete analyzer can test, lowest reagent and sample consumption, lower cost per analysis, very low or No carry over, easy to use and maintain, stable calibration and walkaway solution.

A specific channel or manifold requirement limits the number of wet chemical parameters a FIA or SFA or CFA can test per sample. Increasing number of channels increases the cost of the equipment proportionately. Thermo Scientific Gallery discrete analyzers, have 12 filter position, equivalent to 12 Channels in Flow injection analyzer, allows up to 20 different wet chemical parameters per sample to be tested.

What are the advantages of discrete analyzers overflow injection or Segmented Flow analyzers?

What is better for automating wet chemical analysis?

If a laboratory is looking for an easy to use high throughput, expandable, multiparameter, wet chemistry analyzer for large numbers of samples, then integrated discrete analyzers are better suited than any type of flow analyzers. If your lab still relies on traditional flow injection analysis or segmented flow analysis, the benefits of high throughput, multi-parameter analysis are within reach. With Gallery and Gallery Plus discrete analyzers, you can put the power of technology to work for you— helping you deliver more results in less time. Our technical specialist can help transfer your existing photometric or FIA method to Gallery platform to ensure complete success.

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Gallery and Gallery Plus discrete analyzers provide an integrated platform for photometric and electrochemical analyses, which can be run in parallel. Discrete cell technology allows for simultaneous measurement of several different tests for the same sample, eliminating method changeover time. Each reaction cell is isolated and temperature-stabilized, to provide highly controlled reaction conditions. Gallery discrete analyzers are able to achieve very low detection levels, and their sophisticated dilution features help to manage a wide concentration range without user intervention.

Learn more about the products

Gallery discrete analyzers automate labor-intensive and time-consuming malt, beer, wine, juice, industrial water and wastewater testing in compliance with several regulatory methods ISO, AOAC, ASBC, OIV, IDF. The Gallery Discrete analyzers are ideal for environmental, industrial, agricultural, oceanographic laboratories analyzing a wide variety of water sample types and matrices. Typical applications include analysis of drinking water, wastewater, ground water, soil, and surface water as per US EPA, ASTM and DIN and other regulatory methods.

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