diff --git a/yarn-project/foundation/src/fields/fields.ts b/yarn-project/foundation/src/fields/fields.ts
index 33050507e66..8939b7adb7c 100644
--- a/yarn-project/foundation/src/fields/fields.ts
+++ b/yarn-project/foundation/src/fields/fields.ts
@@ -47,7 +47,7 @@ abstract class BaseField {
   }
 
   protected constructor(value: number | bigint | boolean | BaseField | Buffer) {
-    if (value instanceof Buffer) {
+    if (Buffer.isBuffer(value)) {
       if (value.length > BaseField.SIZE_IN_BYTES) {
         throw new Error(`Value length ${value.length} exceeds ${BaseField.SIZE_IN_BYTES}`);
       }
diff --git a/yarn-project/foundation/src/json-rpc/convert.ts b/yarn-project/foundation/src/json-rpc/convert.ts
index 7bdb85aa34b..7e1de2cbd4b 100644
--- a/yarn-project/foundation/src/json-rpc/convert.ts
+++ b/yarn-project/foundation/src/json-rpc/convert.ts
@@ -130,7 +130,7 @@ export function convertToJsonObj(cc: ClassConverter, obj: any): any {
   }
 
   // Is this a Node buffer?
-  if (obj instanceof Buffer) {
+  if (Buffer.isBuffer(obj)) {
     return { type: 'Buffer', data: obj.toString('base64') };
   }
 
diff --git a/yarn-project/simulator/src/avm/serialization/instruction_serialization.ts b/yarn-project/simulator/src/avm/serialization/instruction_serialization.ts
index 949dc4b2819..e9ea67945fd 100644
--- a/yarn-project/simulator/src/avm/serialization/instruction_serialization.ts
+++ b/yarn-project/simulator/src/avm/serialization/instruction_serialization.ts
@@ -158,7 +158,7 @@ function writeBigInt128BE(this: Buffer, value: bigint): void {
  */
 export function deserialize(cursor: BufferCursor | Buffer, operands: OperandType[]): (number | bigint)[] {
   const argValues = [];
-  if (cursor instanceof Buffer) {
+  if (Buffer.isBuffer(cursor)) {
     cursor = new BufferCursor(cursor);
   }