UniCo AS-37 10 cm Pathlength Cuvette Holder

Overview

The UniCo AS-37 is a precision-engineered cuvette holder designed exclusively for 10 cm (100 mm) optical pathlength rectangular cuvettes used in ultraviolet–visible (UV–Vis) spectrophotometry. Unlike generic sample holders, the AS-37 implements a rigid, alignment-optimized mechanical architecture to ensure consistent and repeatable positioning of cuvettes within the light beam path—critical for high-accuracy absorbance measurements at extended pathlengths. Its design adheres to fundamental photometric principles where pathlength directly influences absorbance linearity (per Beer–Lambert law), making precise cuvette seating essential for quantitative analysis of low-concentration analytes or highly diluted samples. The holder serves as a dedicated accessory for UniCo UV–Vis spectrophotometers—including models such as the UV-2600 and UV-2800 series—and maintains optical axis alignment through machined slot tolerances ≤ ±0.15 mm, minimizing beam deviation and stray light contribution.

Key Features

• Four precisely spaced, parallel cuvette slots—each engineered for stable vertical insertion and lateral confinement of standard 12.5 × 12.5 mm cross-section 10 cm pathlength cuvettes (e.g., Hellma 176-QS, Starna 21-Q-10)
• Low-mass structural frame fabricated from anodized aluminum alloy—providing dimensional stability across ambient temperature fluctuations (20–25 °C) without thermal drift-induced misalignment
• Non-reflective matte black interior surface finish—reducing internal light scatter and improving signal-to-noise ratio during low-transmittance measurements
• Compact footprint (150 × 110 × 70 mm) and lightweight construction (0.6 kg)—enabling seamless integration into crowded benchtop configurations and compatibility with automated sample changers requiring minimal Z-axis clearance
• Tool-free cuvette loading/unloading—featuring chamfered slot entrances and tactile depth stops to prevent over-insertion and ensure reproducible optical path registration

Sample Compatibility & Compliance

The AS-37 accommodates industry-standard 10 cm pathlength cuvettes made from UV-grade fused silica, borosilicate glass, or optical acrylic—provided outer dimensions conform to ISO 10810:2021 specifications for rectangular cuvettes (12.5 ± 0.2 mm width/depth). It is not intended for use with tapered, round-bottomed, or micro-volume cuvettes. While UniCo does not certify third-party instrument interoperability, the holder’s mechanical interface aligns with the DIN 19643-compliant sample compartment geometry found in many mid-range UV–Vis systems (e.g., Shimadzu UV-1900, Agilent Cary 60). No regulatory certification (e.g., CE, UKCA) applies to this passive mechanical accessory; however, its use supports compliance with ISO/IEC 17025:2017 clause 6.4.10 (equipment suitability verification) when validated alongside host spectrophotometer performance qualification protocols.

Software & Data Management

As a purely mechanical accessory, the AS-37 requires no firmware, drivers, or software integration. Its function is independent of instrument control systems—no USB, Bluetooth, or RS-232 interfaces are present. However, when used with UniCo’s UVWin software (v5.2+), the holder enables standardized multi-cuvette measurement workflows: users may define sequential absorbance scans across all four positions using predefined method templates, with automatic data tagging by slot index (e.g., “AS-37_Slot1”, “AS-37_Slot4”). Audit trails generated under UVWin comply with FDA 21 CFR Part 11 requirements when deployed on validated Windows platforms with enabled electronic signature modules and system access controls.

Applications

• Environmental water analysis—measuring trace nitrate (NO₃⁻) or phosphate (PO₄³⁻) concentrations in municipal wastewater effluents using 10 cm pathlength cells to enhance detection sensitivity below 0.05 mg/L
• Pharmaceutical dissolution testing—quantifying low-dose active pharmaceutical ingredients (APIs) in dissolution media where extended pathlength improves precision per USP spectrophotometric assay guidelines
• Academic spectroscopy labs—supporting teaching experiments on Beer–Lambert law validation, molar absorptivity determination, and spectral interference studies requiring matched-pathlength replicate measurements
• Quality control of optical materials—evaluating transmission homogeneity across large-area quartz substrates via spatially resolved 10 cm beam profiling

FAQ

Is the AS-37 compatible with 1 cm cuvettes?

No. The slot depth and stop geometry are dimensionally fixed for 100 mm pathlength cuvettes only. Inserting shorter cuvettes results in improper beam intersection and invalid absorbance values.
Can it be sterilized for biological applications?

Yes—autoclaving at 121 °C for 20 minutes is permissible due to aluminum’s thermal stability; however, repeated cycles may affect anodized surface integrity. Ethanol wipe-down is recommended for routine decontamination.
Does it include cuvettes?

No. The AS-37 is sold as a holder only. Compatible 10 cm pathlength cuvettes must be ordered separately (e.g., UniCo CUV-10Q for quartz, CUV-10G for glass).
What is the maximum operating temperature range?

Mechanical functionality is guaranteed between 15 °C and 40 °C. Prolonged exposure above 50 °C may induce minor coefficient-of-thermal-expansion mismatch between aluminum housing and glass cuvettes, potentially affecting positional repeatability.
Is there a mounting option for spectrometer rail systems?

Not natively. The base lacks tapped holes or dovetail interfaces. Custom adapter plates can be fabricated using the 150 × 110 mm footprint and M3 threaded insert points (available upon request from UniCo Technical Support).