Zinc Content Assay Kit (Nitro-PAPS, Micro Method)

Cat. No.: Z1524127

GRADE & PURITY BioReagent, Suitable for Analysis, Single Standard Method

Specifications

Sinonimi

Blood Zinc Concentration Assay Kit (Micro Method) | Blood Zinc Concentration Assay Kit

Specifiche e purezza

BioReagent, Suitable for Analysis, Single Standard Method

Grado

BioReagent, Single Standard Method, Suitable for Analysis

Applicazione

Cell Metabolism

Metodo di rilevamento

Spectrophotometric

Quantitative

Quantitative

Detection instrument

Microplate reader

Detection wavelength

570nm

Sensibilità

Light-sensitive

Detection duration

15 min

Stoccaggio e spedizione

Condizioni di conservazione di stoccaggio

Store at 2-8°C

Spedito in

Wet ice

Stabilità e conservazione

Each component has a shelf life of 12 months under corresponding storage conditions.

Contents & Storage

Z1524127	Components	Appearance	100T	Storage	Quantity Per Test
Z1524127A	Chromogenic Agent A	Liquid	16 mL	2-8℃. Store in the dark.	160 μL
Z1524127B	Chromogenic Agent B	Liquid	4 mL	2-8℃. Store in the dark.	40 μL
Z1524127C	Standard Solution (36.7µmol/L)	Liquid	1 mL	2-8℃. Store in the dark.	As needed

Application Protocols

Follow the kit’s Instructions for Use (IFU) for definitive steps. The outline below is an example microplate workflow (general literature), provided to aid planning. It is not a specification for this item.

Example micro-method (96-well plate):

1. Equilibrate all components to room temperature; protect the chromogenic reagent from light.
2. Prepare standards: Dilute the zinc stock standard with assay buffer to prepare a series (e.g., 0, 0.5, 1, 2, 3, 5 µM). Include a reagent blank.
3. Samples: Clarify by centrifugation if turbid. If protein-rich, consider deproteinization or validated dilution. Avoid EDTA-containing matrices.
4. Dispense micro-volumes (e.g., 50–200 µL total per well) of standards and samples in duplicate/triplicate.
5. Add working Nitro‑PAPS reagent to each well in the same order/timing. Mix gently without introducing bubbles.
6. Incubate for the method-defined time (commonly 5–10 min, protected from light).
7. Read absorbance at the specified wavelength for the Zn–Nitro‑PAPS complex (often 550–570 nm, literature). Use pathlength correction or calibrate in-plate.
8. Calculations: Subtract blank; fit a standard curve (linear through origin or with intercept, as validated). Apply dilution factors. For single-standard methods, normalize response to the standard as per the kit’s instructions.

Controls/QC:

• Reagent blank, matrix blank, and spiked recovery samples.
• Periodic check standards to monitor drift.

Instrument: Any microplate reader or spectrophotometer capable of the required wavelength.

Biological Roles

This section discusses zinc biology in general (not product specifications or medical claims).

• Essential trace element: Zn2+ is a structural and catalytic cofactor in hundreds of enzymes (e.g., dehydrogenases, DNA/RNA polymerases) and in zinc-finger transcription factors that regulate gene expression.
• Structural roles: Stabilizes protein domains via tetrahedral coordination with Cys/His residues; contributes to protein folding and DNA-binding motifs.
• Catalytic roles: Acts as a Lewis acid to activate substrates/water (e.g., carbonic anhydrase, metalloproteases) and participates in hydrolysis and redox-insensitive catalytic processes.
• Homeostasis: Cellular zinc is tightly regulated by importers (ZIP, SLC39), exporters (ZnT, SLC30), and metallothioneins. Dysregulation can perturb signaling, oxidative stress responses, and enzyme activity.
• Lab relevance: Accurate quantification of total or labile zinc pools supports studies in enzymology, metallomics, nutrition, and cell biology. Sample preparation should distinguish between free, protein-bound, and total zinc depending on the research question.

Practical considerations for measurement:

• Avoid chelating anticoagulants (EDTA/citrate); heparin or no-additive tubes are preferred when zinc is the analyte of interest.
• Use trace-metal–clean technique to prevent contamination from labware, dust, or fingerprints, which can carry ng–µg levels of Zn.

Buffer Applications

This product is not a general-purpose biological buffer. It includes assay-specific buffers optimized for zinc–Nitro‑PAPS complexation. Users should follow the kit instructions for buffer composition and pH.

• Buffer composition/pH: Not specified for this item; refer to CoA/Spec Sheet and IFU.
• Practical notes (general): Maintain the method pH to ensure reproducible complex formation. Introducing external buffers containing chelators (e.g., Tris with residual amines, phosphate with trace metals) may impact performance; validate if substituting any buffer components.

Green Alternatives

• Micro-method advantages (item-relevant): The micro-volume format reduces reagent consumption and hazardous waste compared with macro cuvette assays, aligning with green chemistry’s waste minimization (Principle 1) and safer solvents/auxiliaries (Principle 5) when used in water.

Comparison of zinc determination approaches (general):

• Colorimetry with Nitro‑PAPS
  • Pros: Aqueous media; simple instrumentation; scalable to microplates; low energy use; rapid.
  • Cons: Potential interferences; dye/complexing reagents contribute to hazardous organic waste; matrix-dependent calibration.
• ICP-OES/ICP-MS
  • Pros: Excellent sensitivity and selectivity; multi-element capability; robust to many matrices after digestion.
  • Cons: High capital/energy cost; requires acid digestion and argon; larger environmental footprint per sample.
• Flame/Graphite Furnace AAS
  • Pros: Good sensitivity for Zn; established in many labs.
  • Cons: Requires metal standards and gases; lower throughput than microplate assays.

Greening tips (general good practice):

• Use microplates to minimize volumes; seal plates to reduce evaporation and repeats.
• Prepare only the amount of working reagent needed for the day to limit expired waste.
• Segregate metal-containing waste for appropriate recycling/disposal.
• Avoid cyanide-based masking agents; prefer benign complexants where effective.

Pharmaceutical Uses

No therapeutic or clinical claims are made for this research-use-only product.

General laboratory/QA applications (non-clinical):

• Excipient/raw material testing: Colorimetric determination of trace zinc in process water, buffers, or excipients during formulation development.
• In-process control: Monitoring zinc carryover or leachables during manufacturing development studies (e.g., contact with galvanized equipment).
• Device/material studies: Assessing zinc release from experimental materials/coatings in simulated media.

Regulatory notes (general):

• This kit is not a compendial method. For GMP/compendial testing (e.g., USP, EP), validate the method for specificity, linearity, accuracy, precision, range, LOD/LOQ, and robustness per ICH Q2(R1) or applicable guidance, or employ pharmacopeial/ICP methods as required.

Physical Properties

As a multi-component kit, there is no single set of physical constants (bp/mp/density) for the product.

• Item-specific physical specs (bp, mp, density, refractive index, pKa, water/peroxide/metal limits, UV cutoff): Not specified for this item; refer to CoA/Spec Sheet.

General/assay-relevant properties (literature, not product specifications):

• Detection mode: Colorimetric (visible).
• Typical measurement wavelength for Zn–Nitro‑PAPS complexes: approximately 550–570 nm (literature; exact λmax depends on formulation and pH). Always follow the kit IFU for the required wavelength.
• Working matrix: Aqueous buffers; micro-method supports microplate cuvette pathlengths (96-well/384-well) or microcuvettes.
• Typical pH window for complex formation: mildly alkaline (commonly pH ~8–9 in literature), chosen to favor Zn2+ chelation while minimizing interference; actual pH is method-dependent.

Practical notes (general):

• Use metal-free water (e.g., 18.2 MΩ·cm) and acid-washed, metal-free plasticware to avoid exogenous Zn.
• Glass can leach trace metals; high-purity, trace-metal–certified plastics are preferred for ultra-trace analyses.

Quality and Grades

• Item-specific grades (from Product Data):
  • BioReagent: Components are suitable for biological/biochemical laboratory use where low background and consistent performance are required.
  • Suitable for Analysis: Assembled and qualified for analytical measurement of zinc content using the provided method.
  • Single Standard Method: The kit is configured to use a single-point calibration approach (per the method instructions) for routine quantification. This can streamline workflow where matrix effects are controlled. For demanding matrices or regulatory work, multi-point calibration may be preferred; validate per your SOP.

What the grades imply (general guidance):

• BioReagent grade emphasizes low contaminants that could interfere with biochemical assays, with batch-to-batch consistency.
• “Suitable for Analysis” indicates that reagents, buffers, and the zinc standard are formulated for analytical readout (e.g., defined pH/ionic strength to optimize chromogenic response).
• Stabilizers/Preservatives: Not specified for this item; refer to CoA/Spec Sheet.

Quality control recommendations (user side):

• Verify linearity and accuracy with an in-matrix spike recovery or a multi-level standard curve when bringing the method into a new sample type.
• Include reagent blank controls to establish background and monitor drift.
• Run periodic QC checks with certified reference materials when applicable.

Reaction and Applications

• Intended application (from Product Data): Quantitative determination of zinc content using a Nitro‑PAPS colorimetric chemistry in a micro-volume format. For research use only.

Assay chemistry (general, literature):

• Mechanism: Nitro‑PAPS acts as a metallochromic ligand forming a colored Zn–ligand complex under controlled pH. The complex exhibits enhanced absorbance in the visible region; absorbance is proportional to Zn concentration per Beer–Lambert law within a validated linear range.
• Selectivity strategies: pH control and optional masking/conditioning agents suppress interferences from Cu2+, Fe2+/Fe3+, Co2+, Ni2+, and Mn2+. Surfactants can stabilize the complex and improve reproducibility in proteinaceous matrices.
• Detection: Plate reader or spectrophotometer at the method-specified wavelength (often in the 550–570 nm region, literature). Use matched pathlength or pathlength correction for microplates.

Applications and tips:

• Biological samples: Deproteinize or dilute viscous matrices to reduce scattering. Avoid EDTA or use EDTA-free collection tubes.
• Environmental/food: Acidify/digest samples (closed-vessel acid digestion, literature) followed by neutralization/conditioning before measurement.
• Calibration: Single-standard normalization per product grade can be used for routine runs with stable matrices. For new matrices, construct a multi-point curve and assess linearity (r2), LOD/LOQ, and recovery.
• QA/QC: Include reagent blanks, matrix blanks, and spiked controls. Confirm absence of Zn in consumables by running process blanks.

Reaction Conditions

The following guidance reflects general literature practices for Nitro‑PAPS–based zinc colorimetry and micro-method workflows. It is not a specification for this item; follow the kit IFU for exact conditions.

• Matrix: Aqueous. Use metal-free, high-resistivity water. Work at ambient temperature (20–25°C) unless otherwise specified.
• pH and buffers: Mildly alkaline conditions (commonly pH ~8–9 in literature) promote Zn–ligand complex formation and color development. Buffers such as HEPES, Tris, or borate have been used; choose the buffer supplied with the kit.
• Wavelength: Measure absorbance near the method-specific λmax for the Zn–Nitro‑PAPS complex (often 550–570 nm, literature). Employ pathlength correction for microplates or use calibration prepared in the same well format.
• Timing: Color typically develops within minutes; an incubation of 5–15 min at room temperature is common before reading. Verify stability window to avoid drift.
• Interference control:
  • Mask or account for Cu, Fe, Co, Ni, and Mn. Many protocols include masking agents selective against these ions while leaving Zn response intact.
  • Remove or avoid chelators (EDTA, citrate) and thiols that can bind Zn.
• Calibration:
  • Single-standard normalization is supported by the product grade; for new matrices, prepare a 5–7 point standard curve spanning the expected range.
  • Include reagent blanks and matrix blanks.
• Expected performance (literature): Sub-µM to low-µM linear ranges are common in micro-methods, with low ng-level detection in microplate formats depending on pathlength and noise.

Always verify linearity, precision, and recovery in your matrix before routine use.

Safety and Handling

• GHS classification, signal word, hazard statements, pictograms: Not specified for this item; refer to the product SDS for each component.
• General hazards (literature/good practice):
  • Colorimetric reagents (e.g., Nitro‑PAPS) and buffers may be irritants; some components may be harmful if swallowed or cause eye/skin irritation.
  • Complexing/conditioning agents and pH-adjusting components can be corrosive or cause sensitization depending on formulation.
• PPE: Wear lab coat, safety glasses or face shield, and appropriate chemically resistant gloves. Work in a well-ventilated area or fume hood when handling concentrates.
• Incompatibilities: Avoid contact with strong oxidizers and strong acids/bases unless specified by the protocol. Prevent contamination with metals; store away from metal tools/caps.
• Handling tips (assay-specific good practice):
  • Protect chromogenic reagents from light to prevent photodegradation.
  • Use only metal-free plasticware for standards/samples and avoid metal needles or stainless steel tools that can leach Zn.
  • Do not mix components from different lots unless validated.
• First aid (overview; defer to SDS): If on skin/eyes, rinse with water for at least 15 minutes; remove contaminated clothing. If inhaled, move to fresh air. If ingested, rinse mouth and seek medical attention. Provide SDS to healthcare personnel.
• Waste: Collect zinc-containing solutions and azo dye–containing waste in labeled containers for disposal per institutional and local regulations.

Solvent Selection

This is an aqueous colorimetric assay kit; organic solvent selection is generally not applicable.

• Applicable media: Use the provided buffers and water. If sample preparation requires dilution, use high-purity, metal-free water (18.2 MΩ·cm) and trace-metal–certified plastics.
• Miscibility profile: Assay is designed for fully aqueous conditions. Significant organic content (e.g., >5–10% v/v alcohols) can alter complex formation and baseline absorbance; validate if organic cosolvents are unavoidable.
• Sample matrices (general): Serum/plasma, cell lysates, tissue extracts, and environmental waters can be analyzed after appropriate preparation and chelator removal. Avoid EDTA, citrate, and other strong chelators that sequester Zn2+ and suppress signal.
• When to choose this kit vs. alternatives:
  • Choose Nitro‑PAPS micro-method for rapid, microvolume, plate-based throughput with straightforward colorimetric readout.
  • Consider atomic absorption/ICP techniques for ultra-trace quantitation or complex matrices where spectral/chemical interferences cannot be sufficiently masked in colorimetry.

Storage and Reconstitution

• Item-specific storage: Store at 2–8°C. Shipped on wet ice. Protect chromogenic components from light.
• Stability/shelf life: Not specified for this item; refer to CoA/Spec Sheet and kit label.
• Reconstitution: If any component is supplied as a concentrate or lyophilizate, reconstitute with the specified volume of metal-free water or buffer according to the IFU. Do not substitute solvents unless validated.
• Working solutions: Prepare fresh on the day of use unless the IFU provides a validated in-use stability window. Discard if color/background increases or precipitate forms.
• Handling to minimize contamination:
  • Use trace-metal–certified, acid-washed plasticware and metal-free pipette tips.
  • Do not touch inside caps/tubes; avoid metal spatulas or needles.
  • Rinse glassware with dilute acid and metal-free water if glass must be used.
• Freeze–thaw: Follow IFU. In absence of guidance, avoid repeated freeze–thaw of standards/reagents; aliquot if freezing is permitted.
• Shipping/storage excursions: If temperature or light excursions occur, inspect for precipitates/discoloration and verify performance with controls before use.

Structure and Identity

This product is a multi-component colorimetric assay kit for quantitative zinc determination based on the Nitro‑PAPS chromogenic system (micro-volume format). It is not a single, well-defined chemical entity.

• Item-specific facts (from Product Data):
  • Product: Zinc Content Assay Kit (Nitro‑PAPS, Micro Method), SKU Z1524127
  • Grade/Purity: BioReagent, Suitable for Analysis, Single Standard Method
  • Storage: 2–8°C; shipped on wet ice
  • Research use only
• Structural information: Not applicable to the kit as a whole. Individual kit constituents (e.g., Nitro‑PAPS reagent, buffers, zinc standard) are separate chemicals.
• Molecular identifiers (SMILES, InChIKey, CAS, MF, MW): Not specified for this item; refer to CoA/Spec Sheet.

General chemistry (literature):

• Nitro‑PAPS is a pyridylazo-phenol–type metallochromic dye that forms a strongly colored complex with Zn2+ in mildly alkaline aqueous media. The complexation increases visible absorbance, enabling sensitive photometric quantification.
• 2D description (assay principle): solution-phase chelation of Zn2+ by an azo-phenolic ligand to generate an intense color whose magnitude is proportional to zinc concentration under controlled pH and masking conditions.

Synthetic Utility

Not typically applicable. This is an analytical colorimetric assay kit rather than a synthetic reagent or building block. For chemical synthesis workflows, see the Reaction & Applications and Reaction Conditions sections for assay-related chemistry and handling guidance.

Target Specificity

• Item-specific target: Zinc ions (Zn2+) in aqueous samples.
• Specificity notes (general): Nitro‑PAPS colorimetry is selective for Zn2+ under controlled pH with appropriate masking agents; however, several transition metals (Cu2+, Co2+, Ni2+, Fe2+/Fe3+, Mn2+) can interfere if present at comparable or higher concentrations. Protein binding and chelators can reduce apparent Zn.
• Recommended practice: Employ the kit’s prescribed reagents and sequence of addition to maximize selectivity, include blanks and spikes to evaluate matrix effects, and validate specificity for each new sample type.