Diffraction grating spectrophotometer

Introduction

A diffraction grating spectrophotometer is a spectrophotometer that uses a diffraction grating as the dispersing element to separate the light into the wavelengths, and it is used in the analytical laboratories for the measurement of the absorbance and the transmittance spectra of the samples. The diffraction grating spectrophotometer consists of a light source, an entrance slit, a diffraction grating, which disperses the light into the component wavelengths, the optics that direct the dispersed light to the sample and the detector, and a detector, such as the photodiode array or the photomultiplier, and it provides a wavelength selection by the rotation of the grating or by the use of the diode array detection, and it measures the spectrum of the sample; the diffraction grating provides a high dispersion and a high resolution, and the spectrophotometer provides features such as the wavelength scanning, the high resolution, and the measurement over the UV-Vis range, and it is used for the quantitative and the qualitative analysis, for the measurement of the spectra, for the kinetics, for the quality control, and for many other applications; the diffraction grating spectrophotometer is available in various configurations, from the single-beam to the double-beam models, and it is an essential instrument in the analytical laboratory. Diffraction grating spectrophotometers are used in the chemistry and the biology laboratories, in the pharmaceutical industry, in the environmental analysis, in the clinical laboratories, and for many other applications. With their high resolution, diffraction grating spectrophotometers are essential for the spectral analysis.

Diffraction Grating Spectrophotometer LDGS-T2015

Diffraction Grating Spectrophotometer features a wavelength pitch of 10 nm, capturing spectral data at uniform intervals. It is integrated with an anti-flare design, minimizing stray lig...

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Diffraction Grating Spectrophotometer LDGS-T2014

Diffraction Grating Spectrophotometer features a photometric range from 0 to 200% for better visibility and improved image quality. The system has a metamerism index calculation option t...

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Diffraction Grating Spectrophotometer LDGS-T2013

Diffraction Grating Spectrophotometer offers a wavelength range of 400 to 700nm, enabling precise color analysis within the full visible spectrum. It supports enhanced spectral matching ...

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Diffraction Grating Spectrophotometer LDGS-T2012

Diffraction Grating Spectrophotometer supports viewing angles of 2° and 10°, enabling accurate color assessment. It features a high-stability illuminant designed for extended use with ...

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Diffraction Grating Spectrophotometer LDGS-T2011

Diffraction Grating Spectrophotometer offers a reflectance range of 0 to 200%, handling low and high reflectivity surfaces effectively. The system is integrated with a temperature contro...

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Diffraction Grating Spectrophotometer LDGS-T2010

Diffraction Grating Spectrophotometer features the sphere size of Φ 48mm, enhancing light capture and accurate reflectance. It offers multiple detector options, ensuring for the selecti...

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Standards

European Pharmacopoeia 2.2.25-Spectrophotometry, ultraviolet and visible

ASTM E275-08(2022)-Standard Practice for Describing and Measuring Performance of Ultraviolet, Visible, and Near-Infrared Spectrophotometers

ASTM E903-20-Standard Test Method for Solar Absorptance, Reflectance, and Transmittance of Materials Using Integrating Spheres

Complies with the above standards, but is not limited to them.

Features

1. Diffraction grating spectrophotometer for measuring absorbance/transmittance of samples across UV-Vis spectrum.

2. Spectrophotometer with diffraction grating monochromator, light source, sample compartment and digital detector.

3. Suitable for chemistry, biochemistry, pharmaceutical, food, environmental and material science laboratories.

4. Includes spectrophotometer unit, cuvettes, power cord, software (if included), and operation manual.

5. Supports quantitative analysis (Beer-Lambert law), wavelength scans, kinetics, and multi-wavelength measurements.

FAQ

Q1: What testing scenarios is this spectrophotometer mainly applied to?

A: The diffraction grating spectrophotometer is used in chemistry, biochemistry, pharmaceutical, food, environmental, and material science laboratories for measuring the absorbance or transmittance of samples at specific wavelengths across the ultraviolet-visible (UV-Vis) spectrum, enabling quantitative analysis, compound identification, and reaction monitoring via light absorption. It supports chemistry and biochemistry (quantitative analysis of compounds (concentration via Beer-Lambert law: A = epsilon*b*c), enzyme assays (kinetics - measure absorbance change over time, calculate enzyme activity), protein quantification (Bradford, BCA, Lowry assays at 595/562/750 nm; A280 for direct protein), nucleic acid quantification (A260 for DNA/RNA, A260/A280 ratio for purity), reaction monitoring (follow color changes, reaction kinetics), compound identification (absorption spectrum scan - identify chromophores, maximum wavelength lambda max)), pharmaceutical (drug content/assay (API concentration in formulations, dissolution testing (measure drug release over time), purity/impurity testing, stability studies (monitor degradation), raw material testing, compliance with USP/EP monographs (many specify spectrophotometric methods)), food and beverage (nutrient analysis (vitamins, proteins, sugars), color measurement (food color, CIELAB), additive analysis (preservatives, colors, antioxidants), contaminant testing (mycotoxins (aflatoxin B1 at 365 nm), heavy metals (via colorimetric reagents)), quality control), environmental (water quality (nitrate, nitrite, phosphate, ammonia, chlorine, turbidity - via colorimetric methods; EPA/Standard Methods), soil analysis (nutrients, organic matter), air quality (pollutants via colorimetric), heavy metals in water (via colorimetric reagents)), material science (thin film characterization (absorbance, band gap calculation from UV-Vis), coating analysis, polymer UV stability, nanoparticle characterization (surface plasmon resonance for gold/silver nanoparticles - color depends on size/shape)), and education/research (teaching labs (Beer-Lambert law, spectroscopy fundamentals), research (method development, novel compound characterization)). Diffraction grating spectrophotometer principle: A light source (deuterium for UV 190-350 nm, tungsten/halogen for visible 350-1100 nm) emits broad-spectrum light. A diffraction grating (or prism) disperses light into component wavelengths; selected wavelength passes through slit to sample. Light passes through sample (in cuvette); detector (photodiode, PMT, or photomultiplier) measures transmitted light. Absorbance = log10(I0/I), where I0 = incident (blank), I = transmitted. Diffraction grating provides wavelength selection (resolution 0.1-5 nm). Single-beam (one beam, manual blank) or double-beam (splits beam, simultaneous sample/reference, more stable, faster scans). Range: UV-Vis 190-1100 nm (most common); some extend to NIR (up to 2500 nm). See 3256 (benchtop spectrophotometer) for similar product; this entry specifies diffraction grating type. See 3253 (multi-angle spectrophotometer) for color measurement.

Q2: What standards does the spectrophotometer comply with?

A: The diffraction grating spectrophotometer follows relevant ISO, ASTM, USP, EP and GB/T standards including ISO 15511 (spectrophotometry - general), ASTM E958 (verification of spectral bandwidth of UV-Vis spectrophotometers), ASTM E2728 (verification of absorbance scale), USP <857> (UV-Vis spectroscopy - general chapter), USP <1223> (validation of alternative methods), EP 2.2.25 (UV-Vis absorption spectroscopy), and GB/T standards for spectrophotometers. The hardware complies with applicable performance (wavelength accuracy +/- 0.5-2 nm, absorbance accuracy +/- 0.005-0.01 A, spectral bandwidth 0.1-5 nm, stray light <0.1%), EMC (IEC 61326), and safety (IEC 61010). For pharmaceutical use, follow USP/EP monographs (many drug assays specify spectrophotometric methods with exact wavelength and solvent) and cGMP (21 CFR Part 211, equipment qualification IQ/OQ/PQ). For environmental water testing, follow EPA/Standard Methods (e.g., nitrate 352, phosphate 365.5, ammonia 350.1/351.2 - many colorimetric methods use spectrophotometer). For food, follow AOAC/ISO methods. For regulated labs (ISO 17025, GMP), maintain calibration records (wavelength calibration with holmium oxide or didymium filter, absorbance calibration with NIST SRM 930 (neutral density filters) or potassium dichromate, stray light test, as-found/as-left data). For photometric accuracy, use NIST-traceable filters or solutions. Wavelength calibration: holmium oxide glass filter (sharp peaks at 241, 279, 287, 333, 361, 418, 453, 486, 537, 637 nm) or didymium filter. Stray light: sodium iodide (220 nm) or sodium nitrite (340 nm) cutoff filters.

Q3: What is the warranty period for the whole spectrophotometer and key components?

A: The whole diffraction grating spectrophotometer is covered by a 12-24 month warranty (analytical instruments often 1-2 years; some 3 years). The spectrophotometer (optics, grating, detector, electronics, light source housing) and software are covered, while light source lamps (wear - deuterium lamp ~1000-2000 hours, tungsten lamp ~2000-5000 hours; replace when intensity drops or fails), cuvettes (wear/breakable - glass/quartz, can scratch/break; replace as needed), and calibration filters (wear - can degrade over time) are consumables/accessories. Damage from improper use, lamp failure (normal wear), cuvette scratches (use proper handling), liquid spills in sample compartment (corrode optics/electronics - clean immediately), dust contamination (optics - keep covered, clean), using wrong cuvette (glass absorbs UV <300 nm - use quartz for UV; glass for visible only), power surges (use UPS), or unauthorized repair (optics alignment - only qualified service) is excluded. Extended warranty and service contracts (preventive maintenance, lamp replacement, calibration, optics alignment) are common for spectrophotometers. Deuterium lamp lasts 1000-2000 hours (UV range); tungsten lamp 2000-5000 hours (visible); detector 5-10 years; grating 10+ years (if clean); electronics 5-10 years. Cuvettes last 1-5 years with proper care (quartz more durable but expensive).

Q4: Is this device difficult to operate? Is professional training required?

A: Operation is straightforward for lab personnel (blank, insert sample, read absorbance). No professional training required for basic quantitative use, but proper technique (cuvette handling, wavelength selection, calibration) is important for accuracy. We provide operation manuals, installation, and training (1-2 days). Proper setup (place on stable, level bench away from direct sunlight/vibration, connect power (with surge protector/UPS), turn on and warm up (15-30 min for lamp stabilization, especially deuterium), install software (if PC-controlled), verify wavelength (with holmium filter if needed), operation (select mode (fixed wavelength, wavelength scan, kinetics, multi-wavelength), set wavelength (lambda max for analyte - determine from spectrum scan or method), prepare blank (solvent/reagent blank - same matrix as sample without analyte), insert blank (cuvette with blank, wipe cuvette windows with lint-free tissue (Kimwipe can scratch - use lens paper; handle only frosted sides), close lid, zero/blank (set A=0 or %T=100), insert sample (same cuvette or matched cuvette, wipe windows, insert same orientation), read absorbance (wait for stable reading), for wavelength scan: set range (e.g., 200-800 nm), scan speed, resolution; run blank then sample; record spectrum, for kinetics: set wavelength, interval, total time; mix sample, insert quickly, start recording (absorbance vs time), calculate rate/slope, for concentration: use calibration curve (standards of known concentration, measure absorbance, plot A vs c, slope = epsilon*b; unknown concentration = A/slope) or single-point calibration, post-measurement (remove cuvettes, rinse with DI water/solvent, dry or store inverted, turn off lamp (or leave in standby - deuterium lamp life extended by not frequent on/off; follow manual), cover instrument (dust protection), maintenance (daily: wipe exterior, clean sample compartment, check lamp hours; weekly: clean cuvettes, inspect lamp (intensity), clean exterior; monthly: wavelength verification (holmium filter), absorbance verification (NIST filter or K2Cr2O7), clean sample compartment; semi-annually/annually: professional calibration (wavelength, absorbance, stray light, spectral bandwidth), lamp replacement (when hours exceeded or intensity low), optics cleaning/alignment, software update), troubleshooting (no reading / error (lamp off/failed (check lamp hours, replace), sample compartment door open (close), cuvette not inserted (insert), software error (restart), low / unstable absorbance (cuvette windows dirty/fingerprints (wipe with lens paper), bubbles in sample (degas), lamp warming up (wait), wrong wavelength (verify), low lamp intensity (replace lamp), sample too dilute (increase concentration/path length), high absorbance (>2 A - outside linear range, dilute sample), high results (wrong blank (matrix mismatch), contaminated cuvette (clean), calibration error (recalibrate), sample turbidity (scattering causes high apparent absorbance - filter or centrifuge; use turbidity blank), wavelength wrong (verify), wavelength inaccuracy (calibrate with holmium filter), absorbance scale error (calibrate with NIST filter), and safety (OPTICAL/RADIATION (UV light from deuterium lamp (190-350 nm) can damage eyes/skin - do not look directly at light source; sample compartment interlock prevents exposure when open; do not bypass interlock; UV-C (254 nm) is germicidal and harmful), CHEMICAL (samples/reagents may be hazardous (acids, bases, organic solvents, toxic compounds - know SDS, wear PPE (gloves, goggles, lab coat); dispose waste properly; quartz/glass cuvettes with chemicals - handle carefully), ELECTRICAL (proper grounding, do not spill liquid in compartment, unplug before lamp replacement (let lamp cool - hot!), do not use with wet hands), CUVETTE (glass vs quartz: glass absorbs UV (<300 nm) - use quartz (190-2500 nm) for UV; plastic (PMMA, PS) for visible only (340-800 nm), disposable; matched cuvettes for best precision; handle only frosted sides, wipe clear windows with lens paper (not Kimwipe - scratches), do not use scratched cuvettes (scatter light), do not overfill (spill in compartment), fill at least 70% for light path), do not touch grating/optics (dust, fingerprints degrade performance; only qualified service cleans optics), do not move instrument while on (vibration can misalign optics; allow warm-up after move), for UV work: use quartz cuvettes, quartz solvent (some solvents absorb UV (acetone cuts off ~330 nm, benzene ~280 nm; use appropriate solvent (water, methanol, ethanol, acetonitrile are UV-transparent)), for protein A280: nucleic acid contamination (A260/A280 ratio; pure protein ~0.6, pure DNA ~1.8), for kinetics: temperature control (enzyme activity is temp-dependent; use thermostatted cell holder if needed; allow temp equilibration), for regulatory/pharma: follow USP/EP method exactly (wavelength, solvent, path length, calculation), maintain calibration records for ISO 17025/GMP, dispose of lamps properly (deuterium lamps may contain small amount of mercury - recycle per regulations) are important for accurate spectrophotometry.

Q5: What is the typical lead-time for order delivery?

A: Standard models require 7-30 working days. In-stock units can ship within 3-7 working days. Custom configurations or large built-to-order systems may require additional time, and we confirm the exact schedule before order confirmation.

Q6: Is regular calibration required? What is the recommended calibration cycle?

A: Calibration recommended every 6-12 months (or per quality system): wavelength accuracy (with holmium oxide or didymium filter - verify at multiple peaks; +/- 0.5-2 nm), absorbance accuracy (with NIST SRM 930 neutral density filters or potassium dichromate solution - +/- 0.005-0.01 A), stray light (with sodium iodide (220 nm) or sodium nitrite (340 nm) cutoff - <0.1% T), spectral bandwidth (per ASTM E958), and photometric linearity (serial dilutions or filters). Routine checks: wavelength verification (monthly, with holmium filter), absorbance check (weekly/monthly, with standard filter or solution), and lamp intensity (daily or when results seem off). If instrument is moved, lamp replaced, grating serviced, or readings seem off, recalibrate. For ISO 17025/GMP/pharma labs, follow applicable schedules and maintain records (calibration certificates, NIST traceability, as-found/as-left data, filter ID, lamp hours, maintenance logs). For USP/EP compliance, follow general chapter <857>/2.2.25 performance verification. For quantitative work, calibration curve with standards should be run each batch (not just instrument calibration - method calibration). Lamp replacement: when lamp hours exceed manufacturer limit (deuterium ~1000-2000 h, tungsten ~2000-5000 h) or intensity drops >20%; after lamp replacement, recalibrate wavelength/absorbance.

Q7: Are supporting consumables universal?

A: Cuvettes (quartz, glass, plastic - universal from lab supply (Starna, Hellma, Fisher, VWR) but use correct type (quartz for UV, glass/plastic for visible), path length (1 cm standard, 0.1-10 cm available), matched set for precision), light source lamps (deuterium, tungsten - specific to instrument model (use OEM or certified compatible; lamp type/connector varies), calibration filters (holmium, didymium, neutral density - universal from lab supply but use NIST-traceable), and cleaning supplies (lens paper, solvent) are available from lab supply companies, though lamps are instrument-specific (use OEM or certified compatible to maintain intensity/warranty) and some cuvettes are matched sets (use same pair for best precision). Long-term consumable cost includes cuvettes (breakage/scratches, $10-$200/pair quartz), lamp replacement (periodic, $100-$500 for deuterium, $50-$200 tungsten), and calibration filters (periodic verification). Energy cost is low (lamps 50-150 W).

Q8: Can I customize parameters or supporting accessories?

A: Customization includes wavelength range (UV-Vis 190-1100 nm (standard), UV-Vis-NIR 190-2500 nm (extended, InGaAs/PbS detector), visible only 325-1100 nm (cheaper, no deuterium lamp)), optical system (single-beam (simple, cheaper, manual blank) or double-beam (simultaneous reference, more stable, faster scans, more expensive), split-beam), spectral bandwidth (0.1/0.5/1/2/5 nm - narrower = higher resolution, better for sharp peaks; 1-2 nm standard for most quantitative work), detector (photodiode (standard, fast), PMT (photomultiplier, more sensitive for low light, UV), silicon (visible), InGaAs (NIR)), sample handling (standard 10 mm cuvette, micro-cuvette, semi-micro, thermostatted cell holder (Peltier or water-jacketed for kinetics/temp control), sipper (flow-through, high throughput), microplate reader (96-well), fiber optic probe (remote measurement), automated sample changer), software (basic (readout, simple quant) or advanced (wavelength scans, kinetics, multi-component analysis, DNA/protein methods, 21 CFR Part 11 compliance, LIMS integration, data export)), features (auto-wavelength, auto-zero, built-in printer, touchscreen, PC control, lamp saver mode, password protection), accessories (cuvettes (quartz/glass/plastic, various path lengths), spare lamps (deuterium, tungsten), calibration filters (holmium, didymium, neutral density, NIST-traceable), thermostatted cell holder, sipper, microplate adapter, printer, PC/software, validation package (IQ/OQ/PQ for pharma), certifications (CE, ISO 9001, IEC 61010, USP/EP compliance), language and accessories. Additional cuvettes, lamps, and accessories can be ordered separately.

Q9: Does the purchase include on-site installation and commissioning service?

A: Standard delivery includes diffraction grating spectrophotometer, cuvettes (initial), power cord, software (if included), and instruction manual (calibration filters often NOT included - order separately). On-site installation, calibration, and operator training ARE typically included or strongly recommended for spectrophotometers (requires professional setup (lamp installation, warm-up, wavelength/absorbance calibration, optics check), software configuration, and user training on technique (cuvette handling, calibration curves, kinetics, method development); installation by manufacturer or certified technician is standard, especially for GMP/compliance labs). For basic single-beam visible spectrophotometers: self-installation is feasible (unbox, plug in, warm up, calibrate, use) but initial training on technique is recommended. Always warm up lamp, calibrate wavelength/absorbance, and verify with standard before first use. For UV models: deuterium lamp installation and alignment may require technician.

Q10: What types of samples are compatible with this equipment?

A: The diffraction grating spectrophotometer measures absorbance of various liquid samples in cuvettes including chemical solutions (compounds in solvent, reaction mixtures), biological samples (protein solutions, nucleic acids, enzyme assays, cell lysates), pharmaceutical solutions (API in solvent, dissolution samples, formulations), environmental samples (water, soil extracts - after colorimetric reagent addition), food/beverage extracts (vitamins, colors, contaminants), and clear solutions. NOT compatible with: Highly turbid/particulate samples (light scattering causes high apparent absorbance - filter (0.45 um) or centrifuge, or use integrating sphere for turbid samples; use turbidity blank), opaque samples (no light passes - dilute or use reflectance accessory), samples attacking cuvette material (verify cuvette compatibility: quartz for UV and most solvents; glass for visible/aqueous; plastic for visible only, some solvents dissolve plastic), samples outside linear range (absorbance >2 (or >1.5 for best accuracy) - dilute sample; absorbance <0.1 - increase concentration or use longer path length), gases/solids without special accessories (gas cells, solid sampling accessories, integrating sphere for reflectance), and samples requiring wavelength beyond instrument range (e.g., IR >1100 nm - use FTIR; far UV <190 nm - vacuum UV). For UV measurements: use quartz cuvettes and UV-transparent solvents (water, methanol, ethanol, acetonitrile; avoid acetone (cutoff 330 nm), benzene (280 nm), toluene (285 nm)). For fluorescence: spectrophotometer measures absorbance, not fluorescence (use fluorometer for fluorescence). For kinetics: use thermostatted holder for temperature control. For micro-volume samples (nucleic acids): use micro-cuvette or Nanodrop (specialized). IMPORTANT: Diffraction grating spectrophotometer fundamentals: (1) What is it? An instrument that measures how much light a sample absorbs at specific wavelengths. Uses a diffraction grating to select wavelength. UV-Vis range 190-1100 nm. Based on Beer-Lambert law: A = epsilon * b * c (A=absorbance, epsilon=molar absorptivity, b=path length, c=concentration). (2) How it works: - Light source: Deuterium (UV 190-350 nm) + Tungsten/halogen (Vis 350-1100 nm). - Monochromator: Diffraction grating disperses light, selects wavelength. - Sample: Light passes through cuvette with sample. - Detector: Photodiode/PMT measures transmitted light. - Absorbance = log(I0/I). (3) Single vs double beam: - Single: One beam. Measure blank then sample. Cheaper, simpler. - Double: Beam split, simultaneous sample+reference. More stable, faster scans, compensates for lamp drift. More expensive. (4) Key parameters: - Wavelength accuracy: +/- 0.5-2 nm. - Absorbance range: 0-3 A (linear 0.1-1.5 A best). - Spectral bandwidth: 0.1-5 nm. - Stray light: <0.1% T. - Wavelength range: 190-1100 nm (UV-Vis). (5) Applications: - Quantitative: concentration via calibration curve. - Protein: A280, Bradford (595), BCA (562). - Nucleic acid: A260, A260/A280 purity. - Enzyme kinetics: absorbance vs time. - Spectrum scan: identify compounds (lambda max). - Dissolution testing: drug release. - Water quality: nitrate, phosphate, ammonia (colorimetric). - Food: vitamins, colors, contaminants. - Materials: thin films, nanoparticles (SPR). (6) Calibration: - Wavelength: holmium oxide filter (sharp peaks). - Absorbance: NIST SRM 930 filters or K2Cr2O7. - Stray light: NaI (220 nm), NaNO2 (340 nm). - Every 6-12 months + method calibration each batch. (7) Cuvettes: - Quartz: UV-Vis (190-2500 nm), expensive. - Glass: Vis only (>300 nm), cheap. - Plastic: Vis only, disposable. - 1 cm path length standard. - Wipe windows, handle frosted sides. (8) Common errors: - Glass cuvette in UV (no reading below 300 nm). - Fingerprints on cuvette (high absorbance). - Turbid sample (scattering = high A). - Absorbance >2 (non-linear, dilute). - Wrong blank (matrix mismatch). - Lamp not warmed up (unstable). - Wavelength wrong (calibrate). - Solvent absorbs in UV (use UV-transparent solvent). (9) Choosing: - Routine visible (340-1000 nm): Single-beam visible, cheap. - UV-Vis general: Single or double beam UV-Vis. - High precision/scans: Double-beam, narrow bandwidth. - Kinetics/temp: Thermostatted holder. - High throughput: Sipper/autosampler/microplate. - Pharma/GMP: IQ/OQ, 21 CFR Part 11, USP compliance. - Budget: Basic single-beam vs advanced double-beam.